MIDAS Final Meeting

3-7 October 2016

Het Pand

Gent, Belgium

Conference programme and abstract volume

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Welcome to the MIDAS final meeting

Welcome to the final meeting of the MIDAS project, in which we have investigated the environmental impacts of deep-sea mining and gas hydrate production. Three years has been a very short time to study the significant issues related to the environmental implications of these emerging exploitation activities. We have made significant progress but much more remains to be done.

This will be an open meeting for MIDAS scientists and other interested individuals. We are very pleased to hold the meeting in the splendid Het Pand building in the city of Ghent.

During Tuesday to Thursday of this week, technical results will be presented from each of the project work packages, following the flow of the project - from looking at the scale of impacts, to the specific impacts on biological communities and their duration, to working to find solutions to reduce these impacts and finally to making this information available to those developing regulations and policies. This final aspect will be picked up again on Friday when we present our most relevant findings in a science/policy forum where we hope to engage in more wide ranging discussions on the implications of our findings.

So, we wish you an interesting, stimulating and productive week, and hope that this meeting will give you the perfect opportunity to learn about MIDAS results.

Phil Weaver, MIDAS Coordinator October 2016

Emergency contact information

The MIDAS annual meeting 2016 will take place in the “Rector Vermeylen” room at Gent University’s Het Pand building:

Het Pand University of Gent Onderbergen 1, 9000 Gent, Belgium

In case of emergency, the MIDAS Project Manager, Dr Vikki Gunn can be reached on +44 (0) 7745 170955 or email vikki.gunn@seascapeconsultants.co.uk.

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Contents

Programme of talks……….......................................................................................... 4

Abstracts for oral presentations.................................................................................. 9

Abstracts for poster presentation.............................................................................. 70

List of participants..................................................................................................... 84

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Programme of talks

Tuesday 4 October 2016 Open science meeting

Session 1: Geological impacts

08.45 - 09.00 Introduction & welcome (P.Weaver) WP1 09.00 - 09.15 WP1 OVERVIEW: R. James

WP1 09.15 - 09.30 S. Garziglia: Current knowledge and challenges regarding the assessment of the environmental impacts of methane hydrate systems during production

WP1 09.30 - 09.45 Deusner et al: Mechanical issues of gas hydrate dissociation and gas migration in weakly consolidated sediments

WP1 09.45 – 10.00 Choi et al: Geomechanic assessment of hydrate-related geohazards: Case studies on Black Sea and western Svalbard continental margins

WP1 10.00 - 10.15 Ballas et al: Integrated study of the influence of natural gas hydrate dissociation on slope stability in the Danube deep-sea fan, Black Sea

WP1 10.15 - 10.30 Zander et al: Potential impacts of gas hydrate exploitation on slope stability in the Danube deep-sea fan, Black Sea

WP1 10.30 - 10.45 Discussion 10.45 - 11.15 Coffee

WP1 11.15-11.30 Knight et al: Determining sulphide mineral oxidation rates and trace metal release under seafloor conditions

WP1 11.30 - 11.45 Okland et al: Weathering of sulphides at the Arctic Mid-Ocean Ridge

WP1 11.45-12.00 Menendez et al: Sediment-nodule-water interactions in the Clarion Clipperton Fracture Zone

WP1 12.00 - 12.15 James et al: Controls on the distribution of rare earth elements in deep-sea sediments in the North Atlantic Ocean

WP1 12.15 - 12.30 Discussion 12.30 - 13.30 Lunch

Session 2: Plumes in a dynamic environment

WP2 13.45 - 14.00 WP2 OVERVIEW: A. Dale

WP2 14.00 - 14.15 Dale et al. Nodule harvesting plumes in the Clarion-Clipperton Zone. Does variability in the background flow environment make a difference?

WP2 14.15 - 14.30 Aleynik et al: Variability of the flow environment in Clarion-Clipperton fracture Zone with implications for plume behaviour

WP2 14.30 - 14.45 Morato et al: Simulating the potential dispersal of SMS mining sediment plumes with insights on the potential impacts on deep-sea biodiversity and existing human activities in the Azores

WP2 14.45 - 15.00 Peukert et al: Visualizing the influence of small scale morphology on the dispersal and re-sedimentation of plumes

WP2 15.00 - 15.15

Bettencourt et al: Evaluating the effect of mining-related sediment plumes on the sea-bed: a gene expression study using the cold water octocoral Dentomuricea meteor exposed to silica-quartz and hydrothermal vent sediment particles.

WP2 15.15 - 15.30 Pham et al: Effects of deep-sea mining sediments plumes on the physiology and behavior of blackmouth rockfish Helicolenus dactylopterus

WP2 15.30 -15.45 Discussion

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15.45 - 16.15 Coffee break

Session 3: Practices, protocols and standards

WP7 16.15 - 16.30 Murphy et al: WP7 overview

WP8 16.30 - 16.45 Jones et al: Environmental considerations for impact and preservation reference zones for deep-sea mining

WP8 16.45 - 17.00 Durden et al: A framework for robust environmental management of deep-sea mining

WP8 17.00 - 17.15 Turner et al: Ecological risk assessment for deep-sea mining in areas beyond national jurisdiction

WP7/8 17.15 - 17.30 Discussion 17.30 - 18.15 Keynote presentation: Michael Lodge, International Seabed Authority 18.30 - 20.30 Icebreaker reception and posters

Wednesday 5 October 2016 Open science meeting

Session 4: Ecotoxicology

WP3 09.00 - 09.15 WP3 overview: C. Hauton

WP3 09.15 - 09.30 Machon et al: Comparative study of sensory abilities (chemo- and thermoreception) in hydrothermal Alvinocaridid and coastal Palaemonid shrimp

WP3 09.30 - 09.45 Martins et al: Impacts of Cu exposure in the antioxidant defence system of the cold-water Dentomuricea aff. meteor: a deep-sea mining activities scenario

WP3 09.45 - 10.00 Mestre et al: Ecotoxicological impact of deep-sea mining in deep-sea and shallow-water shrimps

WP3 10.00 - 10.15 Brown et al: Evidence of behavioural avoidance of metals in coastal and abyssal sea cucumbers (Phylum Echinodermata)

WP3 10.15 - 10.30 Piquet et al: Relative abundances of methane- and sulfur-oxidizing symbionts in gills of two mussels from deep-sea hydrothermal vents maintained under pressure

10.30 - 11.00 Coffee break

WP3 11.00 - 11.15 Mestre et al: A weight of evidence approach for environmental risk assessment of sediment plumes generated on a mine tailings deposit site - implications for deep-sea mining

WP3 11.15 - 11.30 Duperron et al: Why we must care about the flexible symbioses of deep-sea animals when addressing the impact of mining

WP3 11.30 - 11.45 Discussion

Session 5: Impacts on species connectivity

WP4 11.45 - 12.00 WP4 overview: A. Colaço

WP4 12.00 - 12.15 Stuckas et al: Analyses of genetic connectivity between populations of deep-sea invertebrate species

WP4 12.15 - 12.30 Colaço et al: Key species dispersal and population connectivity at different spatial scales and under different disturbance scenarios at fragmented habitats of the MAR

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12.30 - 13.30 Lunch

WP4 13.45 - 14.00 Sarrazin et al: Faunal colonization processes on organic and inorganic substrata at the Lucky Strike vent field on the Mid-Atlantic Ridge

WP4 14.00 - 14.15 Rakka et al: Reproductive ecology of cold water gorgonian species in the Azores Archipelago: insights and potential impacts upon disturbance

WP4 14.15 - 14.30 Ribeiro et al: Population connectivity patterns of Bathymodiolus azoricus suggest significant vulnerability to environmental disturbance in NE Atlantic hydrothermal vents

WP4 14.30 - 14.45 Taboada et al: Molecular connectivity within the Clarion Clipperton Zone: a case study using a new nodule-encrusting sponge

WP4 14.45 - 15.00 Bonifacio et al: Diversity and distribution patterns of abyssal polynoids (Polychaeta: Polynoidae) across the Clarion Clipperton Fracture Zone (NE Pacific)

WP4 15.00 - 15.15 Glover et al: Evidence-based management of the Clarion-Clipperton Zone mining frontier requires a new, open-access biodiversity library based on DNA taxonomy

WP4 15.15 - 15.30 Discussion 15.30 - 16.00 Coffee

Session 6: Societal framework and legal instruments

WP6 16.00 - 16.20 WP9 overview (K. Gjerde) Gjerde et al: Perspectives on the emerging regulatory regime for deep seabed mining in the Area beyond national jurisdiction

WP6 16.20 - 16.35 M.Gianni: Mining the deep sea: environmental, political, and social challenges

WP6 16.35 - 16.50 Van den Hove et al: Reconciling precaution and urgency via an adaptive approach to deep sea mining

WP6 16.50 - 17.05 J.Ardron: Evaluating the transparency of the International Seabed Authority

WP6 17.05 - 17.20 Johnson et al: Strategic conservation planning for the Area with a focus on Areas of Particular Environmental Interest (the SEMPIA process)

WP6 17.20 - 17.45 Discussion

17.45 - 18.30 Keynote presentation: Matthias Haeckel, GEOMAR

Long-term impacts from manganese nodule mining: current status of the JPIO Mining Impact project

Thursday 6 October 2016 Open science meeting

Session 7: Impacts on ecosystem functioning

WP5 09.00 - 09.15 WP5 overview: A. Sweetman

WP5 09.15 - 09.30 Dell'Anno et al: Impact of mining activities on virus-prokaryote interactions in benthic abyssal ecosystems of the Clarion Clipperton Fracture Zone (Pacific Ocean)

WP5 09.30 - 09.45 Husson et al: First insight on mussel’s response to fluid physico-chemical changes from a modelling approach

WP5 09.45 - 10.00 Martins et al: Effects of deep sea mining on the antioxidant defense system of the cold-water coral Dentomuricea aff. Meteor

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WP5 10.00 - 10.15 Mevenkamp et al: Responses of nematodes to increased copper toxicity, tailings exposure and sediment deposition from in-situ and laboratory experiments

WP5 10.15 - 10.30 Stratmann et al: Impact of deep-sea mining on benthic food webs with special emphasis on megafauna

WP5 10.30 - 10.45 Sweetman et al: Bacteria are key players in the short-term degradation of phytodetritus in abyssal CCZ sediments

10.45 - 11.15 Coffee

Session 8: Ecosystem resilience and recovery

WP6 11.15 - 11.30 WP6 overview: P. Martinez

WP6 11.30 - 11.45 Canals et al: The metal-bearing mine tailings deposit from Portman Bay: A multi-proxy characterisation

WP6 11.45 - 12.00 Dell'Anno et al: Recovery of benthic ecosystem after a submarine eruption in the northeast Atlantic Ocean

WP6 12.00 - 12.15 Gambi et al: Nematode assemblages affected by historical mine tailing discharge in Portman Bay (Southern Spain)

WP6 12.15 - 12.30 Gollner et al: Resilience of benthic deep-sea fauna to mineral mining activities

WP6 12.30 - 12.45 Cuvelier et al: Feasibility and possibility for restoration and mitigation actions in ecosystems impacted by mining

12.45 - 14.00 Lunch

WP6 14.00 - 14.15 Marcon et al: Megabenthic Community Structure Within and Surrounding the DISCOL Experimental Area 26 Years After Simulated Manganese Nodule Mining Disturbance.

WP6 14.15 - 14.30 Hauquier et al: Meiofauna response to physical disturbance at the DEA: the importance of scale to identify long-term effects

WP6 14.30 - 14.45 Vonnahme et al: Effects of simulated deep-sea mining impacts on microbial communities and functions in the DISCOL experimental area.

WP6 14.45 - 15.00 Simon-Lledo et al: Megafauna community patterns related to terrain variations in the abyssal North Pacific

WP6 15.00 - 15.30 Discussion 15.30 - 16.00 Coffee

Session 9: New monitoring technologies

WP10 16.00 - 16.15 WP10 overview: F. Janssen WP10 16.15 - 16.30 Vanreusel et al: Tools for Rapid Biodiversity Assessment in the deep-sea :

an overview. WP10 16.30 - 16.45 Stewart et al: Testing monitoring approaches during an industry-led Field

Testing Cruise WP10 16.45 - 17.00 Schoening et al: Semi-automated image analysis for meter to kilometer

scale habitat mapping at Condor sea mount WP10 17.00 - 17.15 Istenic et al: Monitoring Seafloor Changes from 3D Optical Maps WP10 17.15 - 17.30 Carreira e Silva et al: Restoration tools for cold-water communities

impacted by mining activities WP10 17.30 - 17.45 Discussion

18.00 MIDAS Steering Committee meeting

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Friday 7 October 2016 MIDAS Science-Policy Meeting

09.00 - 09.15 Welcome and introduction

09.15 - 09.35

Principles for the environmental management of deep-sea mining (led by Kristina Gjerde) The common heritage of mankind, EU drivers and research agenda, transparency, the precautionary approach, adaptive management

09.35 - 09.50 Discussion

09.50 - 10.30

Spatial management (led by Dan Jones) • Claim-scale spatial management considerations and defined areas, strategic

and regional environmental management (D. Jones) • Ecosystem and species connectivity (A. Colaco) • Importance of nodules as faunal substrate (A. Vanreusel) • Plumes and plume models (A. Dale)

10.30 - 11.00 Discussion 11.00 - 11.30 Coffee

11.30 - 12.20

Environmental impact assessment (led by David Billett) • Baseline study recommendations and EIA (D. Billett) • High resolution techniques for impact assessment (M. Haeckel) • Recovery and rehabilitation (P. Martinez-Arbizu) • Functional impacts of disturbance (A. Sweetman) • The framework for environmental management of a deep-sea mining project,

EIA (D. Jones)

12.20 - 12.50 Discussion 12.50 - 13.45 Lunch

13.45 - 14.15

The need for environmentally aware mining techniques (led by Kevin Murphy) • Plumes and mining scenario, BAT and BPEO (K. Murphy) • Ecotoxicology (C. Hauton) • Monitoring technology (F. Janssen)

14.15 - 14.45 Discussion 14.45 - 15.00 Final remarks and wrap up

15.00 Meeting close

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Abstracts for oral presentations

Listed in order of presentation

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Current knowledge and challenges regarding the assessment of the environmental impacts of methane hydrate systems during production

Sebastien Garziglia

IFREMER, Institut Française de Recherche pour l’Exploitation de la MER Pointe du Diable, 29280, Plouzané, France

Methane hydrate accumulations in deeply buried sand reservoirs are considered to be the most amenable to existing well-based production technologies. It has however been recognised that, with regard to the environmental impacts of methane production, there is a critical need to gain a comprehensive understanding of the response of gas hydrates systems to both natural and anthropogenic perturbations. This requires a multifaceted approach involving: (1) the appraisal of the geological controls on the occurrence and stability of gas hydrates, (2) the assessment of the volume of gas stored as hydrates in target reservoirs and overburden, (3) the development of environmental change and production scenarios, (4) advanced field and laboratory characterization of the physical properties and thermo-hydro-mechanical behaviour of gas hydrate-bearing and free gas-bearing sediments, (5) the calibration and validation of advanced numerical models against field and laboratory data, (6) the determination of the portion of gas hydrate most prone to dissociation under specific environmental change scenarios, (7) the quantitative estimation of the geomechanical consequences of gas hydrate dissociation through long-term production modelling.

The purpose of this talk is to summarise current knowledge and challenges in these areas in order to lay the basis and framework for the gas hydrate research and development activities that have been carried out during the MIDAS project.

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Mechanical issues of gas hydrate dissociation and gas migration in weakly consolidated sediments

Christian Deusner, Shubhangi Gupta, Elke Kossel, and Matthias Haeckel

GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstr. 1-3, 24148 Kiel, Germany

Mechanical stiffness and strength of marine sediments can be strongly influenced by the presence of gas hydrates. Especially, weakly consolidated near-surface sediments can become stabilized by gas hydrates even at low gas hydrate saturations. During gas hydrate dissociation, however, this intrinsic contribution to sediment strength is lost, and the sediment mechanical behaviour is strongly influenced by hydraulic effects associated with gas release, gas hold-up, multi-phase fluid flow, and permeability changes. Both, the contribution of gas hydrates to composite strength of marine sediments, and the stress-strain behaviour in response to thermo-hydro-chemo-mechanical process coupling is poorly understood, and numerical simulation approaches are often not thoroughly validated. Additionally, gas hydrate formation, dissociation, and fluid migration are strongly influenced by natural heterogeneities, sediment lithology, and structural disturbances. All these factors introduce large uncertainties in geotechnical risk assessment and prediction of large-strain sediment failure and slope destabilization.

Within the MIDAS project, our central objectives were to develop mathematical and numerical tools and strategies for analysing thermo-hydro-chemo-mechanical process coupling during gas production from gas hydrate-bearing sediments, and to identify important factors for sediment stability, as well as potential triggers of large-strain plastic failure relevant to marine sediments of the Danube deep-sea fan (Black Sea). In particular, we focused on analysing scenarios of transient and uneven gas hydrate formation and dissociation, as well as on seep and fracture-related focused gas flow and gas hydrate formation.

Using novel high-pressure triaxial test systems and tomographic tools, experimental studies were carried out with artificial and natural sand samples, and silty-clayish sediments from the Danube area. Our results indicate that alterations in gas hydrate-soil fabrics during gas hydrate formation and dissociation change sediment stiffness and strength behaviour, and thus, bulk gas hydrate saturation is not sufficient to uniquely define sediment geomechanical properties. At homogeneous but low gas hydrate saturations, sandy sediments showed similar or lower peak shear strength than gas hydrate-free sand, which suggests a possibility of reduced frictional resistance in the presence of gas hydrates. Gas hydrates formed in response to focused gas flow through initially water saturated sediment lead to rapid increase in stiffness and strength, which suggests an increased contribution to the mechanical strength of the composite resulting from massive gas hydrates formed at the gas-water interface in the vicinity of gas conduits. Finely-distributed gas released from gas hydrate dissociation tended to accumulate and be retained in the pore space. Overall, our results provide evidence that local and dynamic gas hydrate formation and dissociation, and the thermo-hydro-chemo-mechanical process coupling can noticeably alter the mechanical properties of the sediment, including stiffness and strength. The uncertainties arising from local process dynamics need to be considered in geomechanical risk assessment, which is usually based on homogeneous gas hydrate distributions.

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Geomechanic assessment of hydrate-related geohazards: Case studies on Black Sea and western Svalbard continental margins Jung Chan Choi1, Maarten Vanneste1, Timo Zander2, Shaoli Yang1,

Carl Fredrik Forsberg1, Guillaume Sauvin1

1 Norwegian Geotechnical Institute (NGI), Sognsveien 72, 0806 Oslo, Norway

2 GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstr. 1-3, 24148 Kiel, Germany

Submarine landslides are an important geohazard and often hydrate dissociation is considered as a contributor. The main reason is that the dissociation replaces the solid phase of hydrate into the overpressured gas phase, which makes the subsurface structure softer and weaker, and therefore more prone to failure. Consequently, the dissociation changes the in situ condition of stress and strength of not only the dissociated zone but also beyond. In spite of its importance of field-scale behavior that includes both the dissociated and non-dissociated zones, most of research so far has focused on dissociation-induced weakening on the slope instability. The effects of the overburden (e.g. seabed subsidence and strain softening) on the geohazard are rarely reported, despite the fact that this may lead to secondary geohazards.

This study presents the field-scale impact of hydrate-dissociation-induced geomechanical behavior on submarine slope stability applied to two selected case studies. We analyze the stress redistribution due to hydrate dissociation using finite elements in order to assess the potential consequences (e.g. change in geometry and strength) on slope stabilities and sediment deformation. The simulations were carried out for different cases of a man-made dissociation (i.e. Black Sea Danube deep-sea fan) and a climate change-induced dissociation (i.e. Western shelf of Svalbard) such that we cover various scenarios of hydrate-related geohazards.

The results clearly indicate that the different causes of hydrate dissociation seem to trigger different mechanism of slope instability. When hydrate is dissociated by man-made production, the simulation shows that the main impacts on slope stability are mainly geometry changes of seabed (i.e. production induced subsidence) and shearing-induced strength weakening (i.e. strain softening) of the overburden. The direct effect of strength reduction of dissociated zone (i.e. hydrate reservoir) seems to be minor because the depth of commercially feasible hydrate reservoirs is generally deeper than potential failure depth of critical slopes. However, when the hydrate is dissociated by climate change (e.g. bottom water warming), the dissociation occurs close to the seafloor, where the hydrate stability zone changes, and the strength reduction of the dissociated zone in shallow subsurface seems to directly affect slope stability but not significantly. The case studies indicate that hydrate dissociation itself is unlikely to become a direct cause of submarine slides. However, mechanical consequence of hydrate dissociation (i.e. deformation or mechanical failure due to stress redistribution) may contribute as a secondary factor to trigger slope failure. The geomechanics model for the western shelf of Svalbard also reveals the mechanism of gas leakage due to climate change-induced hydrate dissociation. The simulation estimates tensile failure zone close to the seafloor when the hydrate dissociation are triggered by climate changes. The estimated tensile failure zone, which increases the permeability of the subsurface drastically, could be related to a leakage pathway of observed gas bubble and a secondary contributor to submarine landslides.

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Integrated study of the influence of natural gas hydrate dissociation on slope stability in the Romanian sector of the Black Sea

Grégory BALLAS, Sébastien GARZIGLIA & Nabil SULTAN

IFREMER, Institut Française de Recherche pour l’Exploitation de la MER Pointe du Diable, 29280, Plouzané, France.

The dissociation of methane hydrate may substantially reduce the geomechanical stability of the host sediment by replacing a rigid component (i.e. methane hydrate) with free gas and excess pore water. Following theoretical and experimental studies supporting this view, slope instability and wide-scale gas venting have been recognised as naturally occurring geohazards associated with methane hydrate dissociation. However, to date, no field study has firmly established the role of environmental changes upon the interaction of gas hydrate and slope stability. This is due to the lack of detailed site specific information regarding past changes in pressure and temperature conditions along with uncertainties concerning the volume of gas hydrates and the mechanical properties of the sediment involved. In order to overcome these limitations, the Romanian sector of the Black Sea was considered as a natural laboratory to acquire and monitor data relevant to the study of the factors which may now contribute to the interplay between gas hydrate and submarine slope failure.

Remote sensing data from the water column and sediments were used to guide the selection of probe sounding locations, which in turn have aided in the choice of core samples collection for laboratory measurements. A site of particular interest with respect to geohazard assessment has been identified from evidences of gas venting, sediment deformations and slope failure processes in the vicinity of the landward edge of the gas hydrate stability zone. Chemical analyses suggested that the stability of gas hydrate in this area may be affected by changes of environnemental conditions related to the reconnection of the Black Sea to the Mediterranean, some 9 kyr ago. The results of these analyses together with in situ measurements of pore pressure and temperature conditions were fed into a hydrate stability model revealing that changes of environmental conditions are inducing the retreat of the landward edge of the gas hydrate stability zone. Geotechnical data derived from laboratory and in situ measurements were then used in a model to evaluate the geomechanical consequences that may arise from dissociation of gas hydrates in the retreating landward edge of their stability zone.

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Potential impacts of gas hydrate exploitation on slope stability in the Danube deep-sea fan, Black Sea

Timo Zander1, Jung Chan Choi2, Maarten Vanneste2, Sebastien Garziglia3, Christian Deusner1, Christian Berndt1

1GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstr. 1-3, 24148 Kiel, Germany 2Norwegian Geotechnical Institute (NGI), Sognsveien 72, 0806 Oslo, Norway

3Ifremer, Pointe du Diable, 29280 Plouzané, France

Gas hydrates have been considered a future energy resource for the past two decades as they store vast amounts of methane in the crystalline cage structures. The sandy sediments of the Danube deep-sea fan of the Black Sea have good reservoir conditions. 2D and 3D high-resolution reflection seismic datasets from a paleo channel-levee system in ~1500 m water depth of the Danube Fan reveal abundant evidence of gas hydrates and free gas, by the presence of a distinct bottom simulating reflection (BSR). In the study area, the gas hydrate stability zone (GHSZ) is about 350 m thick. High-amplitude reflections in the channel sediments above and also preliminary result from controlled source electromagnetic (CSEM) profiles point towards coarse-grained (sandy, gravelly) layers with elevated gas hydrate saturation.

For engineering and exploitation activities along a sloping seabed, the seafloor stability should be addressed. In the study area, the bathymetric and seismic data reveal evidence for paleo-failures along the steep levee slopes, suggesting that the area may be prone to sediment failure. Furthermore, reducing the in situ pore pressure in the hydrate reservoirs to allow dissociation and exploitation, invokes an increase in effective stress and therefore a change in the geomechanical conditions within the reservoir and overburden. As a result, gas production from shallow hydrate reservoirs may cause subsidence at the seafloor.

This study focusses on analysing the hazard of slopes that may become unstable during or after the production of gas hydrates and the induced seabed subsidence due to reservoir compaction. Based on seismic and CSEM data from the Danube deep-sea fan, we created a two-dimensional geomechanical model. Initial results estimated the failure surface at the levee slope that has a low Factor of Safety of about 1.26, which is considered to be critically affected by production-induced mechanical behavior. The estimated subsidence at the seafloor after pore pressure depletion of the reservoir is only in the order of centimetres. The preliminary estimation concludes that the effect of production-induced subsidence on the stability of critical slopes will be minor. However, the inherent stability of the slope is still under marginal ranges (less than 1.5); and the material properties and production scenario still have big uncertainties due to lack of in situ data.

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Determining sulphide mineral oxidation rates and trace metal release under seafloor conditions

Robert Knight and Stephen Roberts

Ocean & Earth Science, National Oceanography Centre Southampton, University of Southampton, SO14 3ZH, United Kingdom (R.D.Knight@soton.ac.uk)

The mining of seafloor massive sulphide (SMS) deposits will result in the oxidation of sulphide minerals and the subsequent release of metals into the surrounding environment. Batch reactor experiments have determined likely oxidation and metal release rates from sulphides during sea floor mining.

Monomineralic samples of pyrite, chalcopyrite and sphalerite were reacted with synthetic seawater at temperatures of ~2 oC, under circum-neutral pH (~8.2) and anoxic conditions for up to 73 hours. Monomineralic samples of pyrite, chalcopyrite and sphalerite as well as polymineralic mixtures of these three sulphide phases in all configurations were run under the same pH, temperature and time conditions, but the synthetic seawater was equilibrated with atmosphere.

During initial eight hour experiments, Fe, Cu and Zn were released into synthetic seawater at different rates from pyrite, chalcopyrite and sphalerite, respectively, while Fe-hydroxide phases simultaneously precipitated; a reaction known to occur at pH >5. These hydroxides appear to sequester Fe and Zn from solution in different proportions, but not Cu. As a result, rates of sulphide mineral oxidation cannot be determined from the concentrations of Fe and Zn in solution as they are not representative of sulphide oxidation alone. Increased concentrations of dissolved oxygen likely increase the rate of sulphide mineral oxidation, but also increase the rate of Fe-hydroxide precipitation. This is reflected in the data which show higher concentrations of metals in solution in experiments run under nitrogen compared with those run under atmosphere after eight hours.

In longer term experiments, the release of Fe from pyrite is limited to ~24 hours. This is likely due to the removal of Fe from solution by Fe-hydroxide precipitation as well as the slowing of oxidation reactions following the formation of oxy-hydroxides on pyrite surfaces. In contrast, Cu release from chalcopyrite is continuous and occurs at a steady rate over at least 73 hours. The pattern of Zn release from sphalerite is highly irregular, and does not show the gradual variations exhibited by the other sulphides studied.

Galvanic effects are evident in polymineralic experiments, predominantly the cathodic protection of pyrite by the preferential oxidation of chalcopyrite and sphalerite. The relationship between sphalerite and chalcopyrite remains unclear due to the removal of soluble Zn by Fe-hydroxides. These data demonstrate that Cu is the biggest geochemical concern facing the mining of SMS deposits given its apparent continuous release from chalcopyrite, particularly when considering galvanic effects in the presence of pyrite, and lack of removal from solution by Fe-hydroxide precipitation. This research can be used to help estimate the potential environmental impacts of SMS mining and has implications for the weathering of these deposits on the seafloor.

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Weathering of sulphides at the Arctic Mid-Ocean Ridge Ingeborg Okland, Håkon Dahle, Ingunn H. Thorseth, and Rolf B. Pedersen

University of Bergen, Centre for Geobiology/ Department of Earth Science, Allegaten 41, N-5007 Bergen, Norway Ingeborg.Okland@uib.no

When Seafloor Massive Sulphide deposits are exposed to oxic sea water they weather into Fe-metal-oxyhydroxides. This process is influenced by microbial activity. In this study we use in-situ experiments with pyrite containing incubators to investigate sulphide weathering processes and the microbial communities involved, at the Loki’s Castle vent field (2400 m depth) and the Jan Mayen vent field (600 m depth) at the Arctic Mid-Ocean Ridge in the Norwegian-Greenland Sea. The incubators were placed in an inactive part of a sulphide mound (Loki’s Castle) and in an iron-oxyhydroxide deposit (Jan Mayen). The 5 chambers of each incubator ranged across the sediment-seawater interface at both sites.

After one year exposure, scanning electron microscopy (SEM) investigation revealed development of Fe-oxyhydroxide weathering rims on pyrite from all chambers. There was a difference in rim thickness of pyrite exposed to the sediment (~0.2µm) compared to pyrite exposed to seawater (4-5µm). Also, the pyrite from the Jan Mayen site generally had thicker rims than the pyrite from the Loki’s Castle site. Moreover, spalling of the rims on the most weathered grains, exposing fresh pyrite surfaces to oxidation, was commonly observed. The SEM investigation also revealed a positive correlation between weathering degree and microbial community density. Preliminary results from the microbial community analysis show a high relative abundance of putative sulphide oxidizers suggesting that the community is governing the degradation of pyrite. Assessments of potential environmental impact of mineral dissolution related to deep-sea mining activities should therefore include biogeochemical processes in addition to abiotic geochemical leaching experiments.

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Sediment-nodule-water interactions in the Clarion Clipperton Fracture Zone Amaya Menéndez1, Rachael James1, Callum Harris1, Anna Lichtschlag2,

Steve Roberts1, Kate Peel2, Doug Connelly2

1Ocean and Earth Science, University of Southampton, National Oceanography Centre Southampton, Southampton SO14 3ZH, UK

2Marine Geoscience, National Oceanography Centre Southampton, Southampton SO14 3ZH, UK

The formation of polymetallic nodules at the Clarion-Clipperton Fracture Zone (CCFZ) is a complex biogeochemical process that is thought to be partly controlled by the redox environment in both the water column and the sediment pore waters. The ability to locate nodule sites and the environmental risks associated with deep-sea mining relies on knowledge of these processes.

We have carried out detailed geochemical and mineralogical analysis of polymetallic nodules and their associated sediments and pore waters collected in the UK Claim Area and several locations within the Area of Potential Environmental Interest No.6 (APEI-6) during RRS James Cook cruise JC120 in May 2015. Locations within APEI-6 include areas with different morphological features, including the Deep Plain, Trough, Flat and Ridge.

Nodules from the UK Claim Area have a complex dendritic internal texture. This consists principally of Mn-oxides, and secondary Fe-Mn enriched oxide layers. Si-Al-K rich clay minerals are abundant and occur mostly in pores and fractures. The mineralogy of nodules from the APEI-6 is similar, although a banded (cf dendritic) texture is more common, and Fe-Mn-enriched oxide layers are slightly more abundant. Total rare earth element and yttrium (ΣREY) concentrations are as high as ~1500 ppm in the nodules and ~700 ppm in their associated sediments. Despite their smaller size, nodules from the APEI have generally higher ΣREY (~1500 ppm) than nodules from the UK Claim Area (~800 ppm). The nodules have positive Ce and Ho anomalies and the light REYs are enriched relative to the heavy REYs, indicating that the REY are principally acquired from seawater. The bottom layer of some nodules has a different REY distribution, with a negative Ce anomaly and enrichment in the middle REEs that suggests this layer acquires REY from sediment pore waters. The Mn content of the nodules is similar for both locations (~30 wt%), whereas concentrations of Fe, Co and Ni are slightly higher in nodules from the Ridge area in APEI-6 (respectively, ~7, ~0.3 and ~1.5 wt% vs. ~6, ~0.2 x 103 and ~1 wt%).

In contrast, the chemical compositions of sediments from the two areas are distinctly different. Concentrations of Mn (~0.8 wt%), Ni (~0.03 wt%) and Cu (~0.04 wt%) are highest in the UK Claim Area, whereas ΣREY concentrations are slightly lower (~400 ppm compared to ~700 ppm). In general, REY distribution patterns for bulk sediments show negative Ce and Ho anomalies and enrichment in the middle REEs, which is typical for Pacific sediments (1, 4). Sediments from the UK Claim Area show a sharp increase in Fe and Mn at ~5 cm depth, likely reflecting oxidation and precipitation of Fe- and Mn-oxides phases by oxygen-rich bottom waters (2, 3). This is not observed in sediments from the APEI-6 area.

References: (1) Dubinin, A.V. (2003) Lit. Min. Res. 39(4), 289-307; (2) Mewes K. et al (2014) Deep-Sea Res. 91, 125-141; (3) Rozanov A.G. (2015) Geochem. Intl. 53(11), 987-1001); (4)Toyoda K. et al., (1990) Geochim. Cosmochim. Acta. 54(4), 1093-1103.

18

Controls on the distribution of rare earth elements in deep-sea sediments in the North Atlantic Ocean

Amaya Menendeza, Rachael H. Jamesa, Stephen Robertsa, Kate Peelb, Douglas Connellyb

aOcean and Earth Science, National Oceanography Centre Southampton, University of Southampton Waterfront Campus, European Way, Southampton SO14 3ZH, UK

bNational Oceanography Centre, Waterfront Campus, University of Southampton, Southampton SO14 3ZH, UK

Deep-sea sediments can contain relatively high concentrations of rare earth elements and yttrium (REY), with a growing interest in their exploitation as an alternative to land-based REY resources. To understand the processes that lead to enrichment of the REY in deep-sea sediments, we have undertaken a detailed geochemical study of sediments recovered from the Atlantic Ocean, on a transect along ~24 ˚N that includes the deep Nares Abyssal Plain and the Canary and North America Basins.

Total REY concentrations (ΣREY) range from 7.99 to 513 ppm, and total concentrations of the heavy REY (Eu - Lu) range from 0.993 to 56.3 ppm. REY concentrations are highest in slowly accumulating pelagic red clays, especially in samples that contain ferromanganese micronodules. Factor analysis reveals that hydrogenous Fe- and Mn-(oxyhydr)oxides are the primary REY carrier phase in the red clays. In situ analysis of individual micronodules confirms that they have high ΣREY (up to 3620 ppm).

The ΣREY content of North Atlantic deep-sea sediments is ~4 times lower than in Pacific deep-sea sediments. We calculate that the area of seafloor required to extract ~10% of the global annual REY demand is ~100 km2, assuming removal of the upper 1m of sediment.

19

Nodule harvesting plumes in the Clarion-Clipperton Zone: Does variability in the background flow environment make a difference?

Andrew Dale (SAMS), Dmitry Aleynik (SAMS), Kevin Murphy (ERM), Mark Inall (SAMS), Annemiek Vink (BGR), Dan Jones (NOC), Jennifer Durden (NOC)

The nature of plumes generated by nodule harvesting depends crucially on the flow environment that the plume encounters – its current speeds, mixing levels and variability. The nodule fields of the Clarion-Clipperton Zone are, in general, a low energy environment, however periods of enhanced current speeds do occur during the passage of large, remotely-generated surface eddies. In addition, local interaction of flow with abyssal hills and other topography is predicted to lead to locally elevated current speeds and mixing.

We consider a scenario in which nodule collection is continuous for 1 one year, achieving complete spatial coverage of a 12 km by 12 km region of the seabed (Fig. 1). Ambient sediment is directly suspended and mixed into a plume in the wake of a collection device. Using particle-tracking techniques, this directly-suspended plume is simulated as a cloud of particles representing a realistic distribution of particle sizes and sinking rates. The plume model is placed within contextual flow environments generated by a three-dimensional hydrodynamic model (MITgcm). The intent is to examine the behaviour of the plume in a range of environments that is representative of those present in the Clarion-Clipperton Zone (Fig. 2). Uncertainties remain with respect to the small-scale dynamics of the plume immediately following passage of the collector, with respect to the sinking speed and potential flocculation of particles, and with respect to aspects of the flow environment that are not represented in the model.

Rates and depths of sediment settlement (Fig. 1), as well as water column sediment concentrations, can be derived from the model for the cases considered. These are being used to develop a ‘decision tree’ for initial estimation of plume behaviour at a site. Translation from such plume metrics to a measure of impact, however, requires greater knowledge of the threshold concentrations and settlement rates at which ecological impact becomes significant.

Figure 1: Plan view of the simulated depth of settled sediment after one year of nodule collection following complete coverage of the blue box. In this example, plume advection is driven by observed near-bed currents.

Figure 2: The simulated sediment plume (blue) downstream of an abyssal hill (white contours) in conditions that lead to formation of a vortex street. The cumulative depth of settled sediment is shaded.

20

Variability of the flow environment in Clarion-Clipperton fracture Zone with implications for plume behaviour

Dmitry Aleynik1, Andrew Dale1, Mark Inall1, Annemiek Vink2

1SAMS, 2BGR

The proposed industrial collection of polymetallic nodules in the Central Tropical Pacific will generate plumes of suspended sediment, which may be environmentally harmful and present operational difficulties for contractors. The nature and impact of these plumes will depend on the ambient flow. While the deep sea is low in energy compared with surface waters, it can also be highly turbulent, because the vertical density gradient, which suppresses turbulence, is weak. The ability to predict the effect of plumes spreading in the abyssal ocean is limited by incomplete understanding of flow processes and their variability in the deep sea. It is shown here that, deep beneath the ocean surface, the low-energy environment can be an order of magnitude more energetic for periods of weeks during the passage of mesoscale eddies from a remote source. We traced eddies back to their origin over eight months (on average) and identified their energy source as offshore winds blowing through the gaps in mountains of Central America, thousands of kilometres away (Fig.1). Abyssal current variability reflects comparable contributions from tides, surface winds and passing ocean vortices. Five high current events were observed over several weeks in the Eastern segment of the Clarion-Clipperton Fracture Zone, when, in a layer 20m above seabed, the current speed exceeded the resuspension level1 (3-5 times higher than the two-year averaged speed of 3.8±2.0 cm·s-1). During periods of relatively high flow, plumes are expected to spread more widely and disperse more rapidly, while supplemented by natural sediment resuspension. Such variability of the flow regimes is typical in the deep sea, suggesting that plume impacts should be evaluated in a representative range of conditions.

Figure 1. (a) Backtrack of 5 mesoscale eddies to the CCZ (white boxes), labelled I-V, and their travel duration in days; (b) Satelite image of Hurricane Carlota during the generation od Eddy I 2; (c) Sea Surface Height (SSH) anomaly and surface geostrophic velocity (AVISO 3) on the arrival date (2013.04.11) of the eddy I at the current meter mooring site, shown with stars; (d) the 3D spreading pattern of a neutrally buoyant plume (colours indicate tracer concentration) over bathymetry (contour interval 50m) on the 4th day of the near-field experiment with a localised MIT-gcm4 model.

21

Simulating the potential dispersal of SMS mining sediment plumes with insights on the potential impacts on deep-sea biodiversity and existing human

activities in the Azores Telmo Morato, Manuela Juliano, Ana Colaço, Marina Carreiro-Silva,

Inês Martins, Christopher K. Pham

Istituto do Mar, University of the Azores, Portugal

The recognition that the deep sea could provide a valuable source of scarce metals has become increasingly widespread in the past years. To date, no commercial deep-sea mining (DSM) has occurred anywhere in the world but the activity is likely to happen any time soon and is anticipated to cause significant impacts on the marine environment and other human activities. The scale and nature of these impacts remains uncertain and depends on the target resource and its associated ecosystems but will involve extensive physical destruction of the seabed, alteration in hydrothermal circulation at the active vent sites and produce considerable sediment plumes. These plumes will potentially contain high concentrations of heavy metals, extremely toxic to the general deep-sea fauna. There is therefore an urgent need to assess the nature and scales of the potential impacts of DSM, how they will affect deep-sea ecosystems and how DSM will interact with other anthropogenic activities. Here 3-D oceanographic models were used to build different mining scenarios, to create maps of the likelihood of an area to be impacted by the plumes, and to quantify potential biodiversity loss and fisheries catch due to deep-sea mining. The return water discharge plume dispersion were found to differ significantly among sites with a potential footprint extending beyond the licensed mining areas. General patterns revealed that plumes may reach the flanks and summits of close topographic features, may have a horizontal footprint of about 50 for 70 km and a large vertical footprint or thickness of about 1,000m depth. Only small seasonal variations on the dispersal patterns were observed. The cumulative bottom thickness of the settled sediment from the return water was estimated to be extremely small with peaks of approximately 0.1 mm only close to the discharge point and with most thickness being smaller than 0.002 mm. In conclusion, simulations of plume dispersal vary significantly between sites, making generalizations hard to adopt. The mesopelagic environment will likely receive most of the deep-sea mining plumes. Simulations suggest potential overlap with pelagic fishing activities.

22

Visualizing the influence of small scale morphology on the dispersal and re-sedimentation of plumes

Anne Peukert, Jens Greinert, Kevin Köser, Timm Schöning

GEOMAR Helmholtz-Centre for Ocean Research Kiel, Germany

AUV-obtained imagery from the German PA I in the CCZ was successfully applied to map the distribution of a sediment cloud after the ‘disturbance’ by an Epibenthic Sledge (SO239). Survey data before and after the disturbance allow a direct estimation of the impact. The images were automatically analyzed for nodule coverage, revealing nodule blanketing after the resettlement of the re-suspended sediment, 16 hours after the disturbance. A visual impact of less than 100 m downstream off the disturbance track can be observed. The correlation with high resolution AUV-based bathymetry reveals that the dispersal is variable in the range of tens of meters and strictly follows the morphology, even in areas of only slight undulating seafloor of less than 1 m vertical difference. Approximate plume heights could be reconstructed from the dispersal distance and current measurements. The results indicate that only a slight change in plume height of only one meter would have an influence of several tens of meters on the lateral dispersal, suggesting to keep the re-suspended material as close to the seafloor as possible in the case of mining. The results highlight the importance of detailed knowledge of the terrain considering mining-related environmental impact studies and should be used to force mining companies to develop technologies that keep the exhaust plume and the tailings as close to the seafloor as possible (within meters!).

23

Evaluating the effect of mining-related sediment plumes on the sea-bed: a gene expression study using the cold water octocoral Dentomuricea meteorexposed

to silica-quartz and hydrothermal vent sediment particles R. Bettencourt1,2,3, A. Freitas1, J. Goulart1, R. Morales1, V. Riou1, A. Goudinho1,2, V. Costa1,2,3, M.

Carreiro-Silva1,2,3, A. Colaço1,2,3 and I. Martins1,2

1IMAR Center, Azores; 2MARE, Marine and Environmental Sciences Centre, Azores; 3Department of Oceanography and Fisheries, University of the Azores

The potential environmental impact from deep-sea mining operations has gained notoriety among marine researchers increasingly concerned about the damage such commercial plans to exploit mineral resources on deep-ocean might cause to the sensitive ecosystems and their associated benthic communities. Among the impacts of deep-sea mining, sediment plumes could have the greatest impact affecting the food web of the area and the composition, density, biomass and diversity of deep-sea fauna, including animals dwelling around the hydrothermal vents.

In an attempt to assess the possible impact of nodule mining on deep-sea macrofauna we set out investigate whether the cold-water octocoral Dentomuricea meteor, under in aquarium conditions would be physiologically affected by exposure to silica-quartz and hydrothermal vent sediment particles over a period of 27 day acclimatization. Gene expressions studies were considered, across sediment exposure experiments, using suspended hydrothermal sediment particles (0.5-70 µm) and suspended inert quartz particles. Comparative gene expression profiles using corals acclimatized to clear sea water as control were performed to put in evidence differences in antioxidant and immune genes from and measured as transcripts (mRNA) levels of complement C3-like, Superoxide dismutase, Carbonic anhydrase, Galaxin, Ferritin, receptor protein tyrosine phosphatase genes. Initial expression studies were carried out to characterized gene transcription levels between animals immediately retrieved from the wild (wild type) and animals acclimatized in clean sea-water over a period of 4 weeks (T0) setting the stage for subsequent gene expression profiles during particles exposure over a period of 27 days. General gene expression in wild-type animals was substantially higher as compared to T0 animals likely attributed to stress-related responses as animals were retrieved from their natural habitats prior to their acclimatization in aquaria. The first initial 72 hours of exposure to sediment particles did not seem to affect the expression of C3—like, SOD, carbonic anhydrase, Galaxin, Ferritin and Prot Tyr-Ph as compared to sea water experimental condition whereas a continuous exposure to particles after 13 days revealed higher gene expression differences in animals exposed to inert and hydrothermal vent particles when compared to control animals. In some instances exposure to hydrothermal vent particles resulted in higher transcriptional levels of Ferritin, Galaxin and Protein Tyr-Ph as compared to corals exposed to quartz particles. Galaxin and Protein Tyr-Ph are involved in calcification and enzymatic processes respectively, whereas Ferritin is involved in iron sequestration and metal detoxification, stress and immune responses as an indirect antibacterial agent. The 27th exposure day marked the end of this study when mortality affected the 3 experimental conditions and compromising subsequent gene expression comparison analyses. Results are being discussed in view of the detrimental effect of sediment particles on the coral Dentomuricea meteor over the course of time and its implication regarding anthropogenic pressure incurring from deep-sea mining upon all organisms inhabiting the areas to be mined, potentially influencing the persistence of susceptible species in such regions.

In addition to gene expression analyses we carried a full RNASeq analysis of D. meteor using illumina paired-end sequencing technology and generated a de novo transcriptome assembly from D. meteor wild-type individuals in order to expedite the discovery of new genes and to assist us in future characterization of gene expression profiles in animals under the effect of mining-generated sediment plumes on the sea-bed.

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Effects of deep-sea mining sediments plumes on the physiology and behavior of blackmouth rockfish Helicolenus dactylopterus

Christopher Kim Pham, António Godinho, Inês Martins, Meri Bilan, Andreia Carvalho, Flavio Rodrigues, Marina Carreiro-Silva, Manuela Ramos, Ana Colaço, Telmo Morato

IMAR/DOP 9901-862 Horta, Portugal

MARE – Marine and Environmental Sciences Centre, 9901-862 Horta Portugal

The potential impacts of deep-sea mining operations remain poorly understood. Although, there is a general consensus that deep-sea ecosystems will undergo irreversible damages, there are few controlled experiments testing the response of deep-sea organisms to mining activities. The objective of this work is to obtain some insights on the effects of mining-related sediment plumes on the physiology and behavior of the bluemouth rockfish Helicolenus dactylopterus, a deep-sea fish known to inhabit seamounts close to areas claimed by mining contractors. In this study, we maintained juvenile H. dactylopterus at two different sediment concentrations (5 and 25 mg L-1) for a period of 26 days. Each treatment (along with a control) included four replicate tanks, each holding two individuals. Sediments (crushed polymetallic sulfide rocks) were pumped in the tanks for a period of 20 hours per day in order to simulate mining discharges. During the trial, a series of responses were measured, including respiration rate, daily behavior patterns and opercular movements. Additionally, diffusive gradients in thin films (DGT’s) were used to monitor the bioavailable labile metal fraction each treatment. Fish were necropsied at T0, T13 and at T26 to evaluate gill damages, oxidative stress and assess metal accumulation in target organs. This presentation will provide a detailed description of the experimental design and preliminary results.

25

Industry management practices Kevin Murphy, ERM

The overall aim of Work Package 7 (WP7) was to describe the industry activities involved in extraction of deep-sea minerals, identify the main activities that may lead to impacts on the environment, define environmental management practices in place to control these impacts, and disseminate this information to the other MIDAS work packages.

Information on likely technologies and working methods was initially obtained from industry stakeholders through a questionnaire, followed up by further discussions. Responses to the information request were received from 21 stakeholders, including MIDAS industry partners. Based on initial and continued consultation, it is clear that the industry is at a very early stage, and that considerable variability and uncertainties remain when considering both technologies and processes for mining. Given the industry’s stage of development, in order to make useful estimates of the potential scale of certain impacts and effects of deep sea mining, WP7 developed a number of mining scenarios. These present reasonable propositions for how mining could be carried out for two main resources of interest polymetallic nodules and seafloor massive sulphides (SMS). Options were selected for the mining method, size and speed of the seafloor mining tool, the targeted resource, production rate, and efficiency of the process.

A register of the main potential impacts of deep sea mining was developed over the course of the project, based predominantly on the outputs of WPs 1 to 6, in order to identify the most important mining activities that will generate impacts and effects on the deep sea environment. For extraction of both polymetallic nodules and SMS, two main zones of impact and effect have been identified, the area of seabed directly affected by mining and the wider area around this where other effects of mining activities may be experienced. The most important impacts and effects of the extractive activities are associated with the area directly affected by mining, where long term loss of existing habitats and associated communities is expected. The impacts and effects of mining within the wider seabed will be mainly linked to the spread and settlement of sediment plumes that are generated during mining. The scenarios developed by WP7, alongside modelling conducted by WP2, were used to estimate the seabed area that could be physically impacted by direct mining and by sediment plumes on an annual basis and over a 30 year lifetime for a mining operation. A large amount of disturbed sediment is expected to settle within the area already directly affected by mining. This area will also experience the highest rates of sedimentation, but some sediment will settle outside the primary footprint. Even where an area of physical impact can be estimated, it is currently very hard to assess what the ecological effects will be as these are not well understood at this stage.

There is limited information about the environmental performance of proposed deep sea mining technologies and about the environmental management practices that may be used in the industry. This was highlighted as a gap during industry consultation, and a need for high level guidance on this area was identified. WP7 developed a generic framework for the consistent application of future BAT and BPEO assessments in deep-sea mining, and identified key development areas for mitigation based on the potential impacts identified in MIDAS. It is likely that the focus of mitigation for deep sea mining will be on limiting the directly mined area within a region to a level that does not threaten ecosystem integrity; and limiting the size of the area which is affected by secondary impacts outside of the mined area.

26

Environmental considerations for impact and preservation reference zones for deep-sea mining

Daniel Jones, Jen Durden, and others

National Oceanography Centre, Southampton

Development of guidance for environmental management of the deep-sea mining industry is important as contractors plan to move from exploration to exploitation activities. Two priorities for environmental management are optimising approaches for monitoring of impacts and mitigating these impacts where possible. The mining code developed for international regulation of deep-sea mining activities stipulates the creation of impact reference zones (IRZ) and preservation reference zones (PRZ) for local monitoring. The environmental management plan for the Clarion Clipperton zone, the first such plan for DSM beyond national jurisdiction, states that the PRZ is also for “ensuring preservation … of biological communities impacted by mining activities”. As such, the approach used for setting and assessing these zones is extremely important in understanding and managing the impacts of DSM activities. This paper presents recommendations for the ISA and the emerging deep-sea mining industry for key considerations to be made when determining these reference zones. The key recommendations are given for the nature of zones, the interaction with sediment plumes and suggestions for additional zones. We recommend that 1) zones should be suitably large to allow for repeat monitoring and to have a protection function, 2) zones should be objectively defined following best-practice and statistically robust approaches, 3) multiple PRZ and IRZ should be considered for each claim, and 4) PRZs should be representative and should contain high quality resource. Sediment plumes are very important in the assessment of reference zones, particularly as, without careful planning, they may extend into PRZ. It may be necessary to create additional IRZ for assessing the impact of plumes (outside the mining area). In addition, only habitats that are suitable for mining are currently covered and it may be necessary for additional PRZs to be designated in areas that represent other important habitats, for example seamounts.

27

A framework for robust environmental management of deep-sea mining

Jennifer M. Durden and Daniel O. B. Jones

National Oceanography Centre, University of Southampton Waterfront Campus, European Way, Southampton, UK SO14 3ZH

The International Seabed Authority (ISA) is legally required to protect the marine environment from any harmful effects of deep-sea mining. However, the environmental data on which to base management decisions are scarce, and the process of environmental management is undefined. We have designed a framework for environmental management that facilitates the development of environmental information and decision-making throughout the phases of a mining project. The framework is based those used in allied industries, but adjusted for unique characteristics of deep-sea mining. It defines the gathering and synthesis of information, and roles and responsibilities of all parties. The environmental management activities at each phase have been designed to enable the implementation of the precautionary principle in decision making, while facilitating adaptive management to improve environmental management as the quantity and quality data increases and technologies are honed. This framework will assist the ISA in its requirements to protect the environment, and benefit contractors and financiers by reducing uncertainty in the process.

28

Ecological risk assessment for deep-sea mining in areas beyond national jurisdiction.

Turner PJ 1, Durden JM 2, Smith AJ 1, Van Dover CL 1, Jones DOB 2

1Duke University Marine Lab, Nicholas School of the Environment, USA. 2 National Oceanography Centre Southampton, University of Southampton Waterfront Campus, UK.

As interest continues to develop for the exploitation of deep-sea minerals, the International Seabed Authority (ISA) is charged with the development of a regulatory framework that guides exploration and exploitation phases within the Area Beyond National Jurisdiction (ABNJ). In its March 2015 action plan, the ISA highlighted a number of high-level issues relating to framework development and actions needed. For the issue of 'effective protection for the marine environment from harmful effects ' the action plan calls for a precautionary risk-management framework. To assist in the development of a risk-management framework, we conducted a deep-sea stakeholder survey that asked experts to assess the vulnerability of deep-sea habitats to a specific mining scenario occurring within the Clarion-Clipperton Zone (i.e. polymetallic nodule deposits), the Northern Mid-Atlantic Ridge (i.e. polymetallic sulphide deposits) and the Western Pacific Seamount Province (i.e. ferromanganese crust deposits). Vulnerability is assessed using measures of ‘scale’, ‘frequency’, ‘functional impact’, ‘resistance’ and ‘recovery time.’ In addition to habitat vulnerability, participants were asked to assess their level of certainty regarding the impact of each risk source, the potential biological consequences of the top-rated risk sources and the level of concern they have for the cumulative effect of mining with other factors impacting deep-sea ecosystems (e.g., bottom trawling, ocean acidification and multiple mining events). The collection of expert-opinion aims to address five key objectives: 1) identify habitats that are most at risk; 2) identify risk sources that drive habitat vulnerability; 3) assess potential biological consequences of risk sources; 4) highlight risk sources of little concern to stakeholders; 5) highlight knowledge gaps for the severity of deep-sea mining risk sources.

29

Comparative study of sensory abilities (chemo- and thermoreception) in hydrothermal Alvinocaridid and coastal Palaemonid shrimp

Julia Machon1, Magali Zbinden1, Philippe Lucas3, Bruce Shillito1, Nelly Léger1, Nicolas Montagné2, Thomas Chertemps2, Juliette Ravaux1

1 Sorbonne Universités, UPMC Univ Paris 06, MNHN, CNRS, IRD, UCBN, UAG, Unité de Biologie des organismes et écosystèmes aquatiques (BOREA, UMR 7208), Equipe Adaptations aux Milieux

Extrêmes, 7 Quai Saint-Bernard, Bâtiment A, 75005 Paris, France 2 Sorbonne Universités, UPMC Univ Paris 06, iEES-Paris, Department of Sensory Ecology, 4 place

Jussieu, 75005 Paris, France 3 iEES-Paris, Department of Sensory Ecology, INRA, Route de Saint-Cyr, 78026 Versailles, France

Hydrothermal vent areas are rich in seafloor massive polymetallic sulfide (SMS) deposits, which are source of interest for a future mineral exploitation of deep ocean floor. Deep-sea mining would represent the first large scale anthropogenic perturbation of hydrothermal vent ecosystems, and could have various impacts on organisms and their habitat. One is the release of mineral particles and potentially toxic compounds that will modify water column properties and may impact organisms’ physiology. The work presented here is part of “Ecotoxicology” Work Package of the MIDAS project.

Chemical sensing is a physiological skill that might be affected by seafloor excavation near vents. In crustaceans, it is the dominant sensory modality, and decapods rely on chemoreception for various behaviors such as food detection, social interactions, navigation and evaluation of habitat (Derby and Weissburg, 2014). Chemoreceptors are present on all appendages and many parts of the body, but antennules are the major chemosensory organs, with specialized chemoreceptors that primarily mediate responses to odorant chemicals (Shepheard 1974). Chemo-detection might play a major role for maintenance of endemic populations of hydrothermal vents, but sensory faculties of these organisms were overall little studied. Because they need to locate fluids that contain reduced chemicals compounds for their symbiotic bacteria, how vent organisms locate hydrothermal activity is a challenging question regarding their chemical senses. Among the commonly accepted potential attractants of hydrothermal fluid are the chemicals compounds and its warm temperature (related to chemo- and thermo-reception respectively). Only few studies provide insights on chemoreception in hydrothermal vents shrimp (Renninger et al., 1995), and even fewer were conducted on thermal sensing. Neither specific thermoreceptors nor putative multimodal thermoreceptors have been identified in crustaceans (Lagerspetz and Vainio, 2006).

We studied the chemo- and thermo-abilities of the hydrothermal shrimp Mirocaris fortunata, abundant on mid-Atlantic ridge vent sites, and its coastal congener Palaemon elegans, with additional approaches in microscopy, electrophysiology, behavior and molecular biology. We described the morphology and ultrastructure of antennules for both species. We developed the first well-established method –called electroantennography- to record the global electrical activity of shrimp antennule in response to soluble odorants. This will allow to test detection of relevant hydrothermal stimuli by shrimp, before studying the behavioral responses elicited by these compounds. For thermo-detection, we showed that hydrothermal shrimp are attracted to warmer temperatures, whereas coastal shrimp do no present this attraction behavior. From gene sequences known in insects and other crustacean models, we identified the sequences of the ionotropic (olfactory) co-receptors IR25a, IR93a and IR8a among four hydrothermal shrimp species and three coastal shrimp species; the same approach will be applied to thermo-receptors.

30

Impacts of Cu exposure in the antioxidant defence system of the cold-water Dentomuricea aff. meteor: a deep-sea mining activities scenario

Inês Martins, J. Goulart, A. Godinho, A. Colaço, R. Bettencourt, M. Carreiro-Silva

IMAR-Department of Oceanography and Fisheries 9901-862 Horta, Portugal

MARE – Marine and Environmental Sciences Centre, 9901-862 Horta Portugal

Previous aquaria-based experiments have shown dissolution and leaching of metals, especially copper (Cu), from the sediment plumes generated during mining activities resulting in a pronounced increase of Cu contamination in the surrounding seawater. Metals are bioavailable to corals from ingestion with food (particulate phase), tissue-facilitated transport, and/or passive diffusion through dissolved phase. With coral communities being particularly vulnerable to metal contamination, resuspension of metal-bearing sediment during mining activities represents an important ecological threat. Herein, the cold-water octocoral Dentomuricea aff. meteor was exposed to Cu concentrations of 0; 5; 30 and 60 µg/L for 15 days, following 15 days of depuration (non-contamination conditions). These concentrations were based on the Cu concentrations found dissolved in seawater during previous aquaria experiment with Polymetallic Sulfide (PMS) deposits. The antioxidant enzymatic activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), heat-shock protein HSP70 and lipid peroxidation were examined in coral fragment tissues to evaluate tissue metabolic specificities under Cu exposure. In addition, coral respiration rates, tissue Cu concentrations and seawater nutrient concentrations (NO3

-, NO2-, NH4

+ and PO43-), were used to compare corals

metabolic states between Cu treatments and depuration. Here we describe the implications of Cu exposure to D. meteor antioxidant defense system, their ability to depurate and recover from Cu contamination and discuss the potential consequences of mining activities on cold-water coral communities.

31

Ecotoxicological impact of deep-sea mining in deep-sea and shallow-water shrimps

N.C. Mestre1, M. Auguste1, A. Brown2, M.A. Cambon-Bonavita3, C. Cardoso1, N. Charlemagne3, V. Cueff-Gauchard3, L. de Sá1, T.G. Fonseca1, C. Hauton2, S. Le Bloa3, J. Machon4, J. Ravaux4, T.L.

Rocha1, B. Shillito4, S. Thatje2, M. Zbinden4, M. J. Bebianno1*

1CIMA, Faculty of Science and Technology, University of Algarve, Campus de Gambelas, 8005 139 Faro, Portugal. 2Ocean and Earth Science, National Oceanography Centre, University of Southampton, Southampton, SO14 3ZH, UK. 3Ifremer, REM/EEP/Laboratoire de Microbiologie des Environnements Extrêmes, UMR 6197, Ifremer, UBO, CNRS, Technopôle Brest Iroise, CS10070, Plouzané, France. 4Sorbonne Universités, UPMC Univ Paris 06, UMR CNRS 7208, MNHN/IRD-207/UCN/UA, Biologie des Organismes et Ecosystèmes Aquatiques", 7 Quai St Bernard, 75252 Cedex 5 Paris, France.

Polymetallic massive sulphide deposits are one of the potential targets for deep-sea mineral extraction given their richness in copper, lead, zinc, precious and trace metals. However, mineral plumes with high concentrations of toxic metals may be released with the exploitation activities, inducing potentially harmful impact in the ecosystems of the deep sea. The aim of this study is to assess the effects of waterborne copper exposure in deep-sea hydrothermal vent shrimps (Rimicaris exoculata and Mirocaris fortunata) and in their shallow-water counterparts (Palaemon elegans, P. serratus and P. varians). The accumulation of copper in different tissues (gills, hepatopancreas and muscle) and a battery of biomarkers was analyzed: oxidative stress (superoxide dismutase - SOD, catalase - CAT, glutathione peroxidases - GPx), metal exposure (metallothionein), biotransformation (glutathione-S-transferases - GST,) and oxidative damage (lipid peroxidation - LPO). The effects of copper in the different species will help to understand the potential effects of deep-sea mining on the deep-sea species and the comparison with their shallow-water relatives will enable to compare adaptations to different environments and to evaluate the potential use of shallow-water species as surrogates to evaluate the ecotoxicological impacts of deep-sea mining. This work was developed under the MIDAS project (managing impacts of deep-sea resource exploitation), funded by the European Comission 7th Framework Programme under the theme “Sustainable management of Europe’s deep sea and sub-seafloor resources” (Grant Agreement 603418).

32

Evidence of behavioural avoidance of metals in coastal and abyssal sea cucumbers (Phylum Echinodermata)

Brown A, Wright R. & Hauton C.

In this short summary we will present the findings of shallow water and abyssal experiments on the response of sea cucumbers (Phylum Echinodermata, Class Holothuroidea) to in situ exposure to copper contaminated sediments. The shallow water Holothuria forskali and the abyssal Peniagone sp. have key roles in sediment bioturbation that mediates nutrient recycling and sediment oxygenation, which in turn facilitates colonisation by infauna in shallow and abyssal habitats, respectively. Laboratory exposures of H. forskali to artificial sediment incubated with different concentrations of copper were used to inform in situ experimental exposures using Peniagone sp.. Behaviour during the exposures was described and tissue samples taken after 96-hours for analyses of antioxidant enzyme profile. For both H. forskali and Peniagone sp., behavioural avoidance mitigated toxic effects of copper as no significant changes in antioxidant enzyme activities (superoxide dismutase and glutathione peroxidase) were detected after exposure to copper in either species. The conservation of behavioural avoidance between the two taxa suggests the shallow-water holothurian, H. forskali, may be used as a behavioural proxy for abyssal taxa to identify the effects of deep-sea mining, potentially reducing the need for costly and difficult in situ experiments.

33

Relative abundances of methane- and sulfur-oxidizing symbionts in gills of two mussels from deep-sea hydrothermal vents maintained under pressure

Bérénice Piquet 1,2, Kamil Szafranski 1,* Adrien Quiles 1, Bruce Shillito 1, and Sébastien Duperron 1,3

1 : Sorbonne Universités, UPMC Univ Paris 06, MNHN, CNRS, IRD, UCBN, UAG, Unité de Biologie des organismes et écosystèmes aquatiques (BOREA, UMR 7208), Equipe Adaptations aux Milieux Extrêmes, 7 Quai

Saint-Bernard, Bâtiment A, 75005 Paris, France

2 : Sorbonne Universités, UPMC Univ Paris 06, CNRS, Unité Adaptation et Diversité en Milieu Marin (AD2M, UMR 7144), Equipe Adaptation et Biologie des Invertébrés en Conditions Extrêmes, Station Biologique de

Roscoff, 29680 Roscoff, France,

3 : Institut Universitaire de France, Paris, France

* : Present Address: Unité d’Ecologie, Systématique et Evolution, Centre National de la Recherche Scientifique UMR 8079, Université Paris-Sud, Orsay, France

The deep-sea mussels Bathymodiolus azoricus (Bivalvia : Mytilidae) and B. puteoserpentis often dominate the endemic macrofauna of mid-atlantic ridge vent sites. As such, they are likely to be impacted by future deep-sea mining activity in vicinity of this deep-sea hydrothermal habitat. Their gills house methane- and sulfur-oxidizing bacteria that sustain most of the mussel’s nutritional requirements. Previous studies indicated that the ratio between methane- and sulfur-oxidizing bacteria did reflect relative availability of their electron donors in their environment. This flexibility is considered a key factor in explaining the ecological success of the species.

To date, the sampling of these mussels from depths between 800 to in excess of 3500m have been performed without hyperbaric chambers, involving great decompression stress. For the first time during the cruises BioBaz 2013 and BICOSE 2014, specimens were recovered in isobaric recovery cells (PERISCOP) under pressurized conditions equivalent to their habitat. Employing 3D FISH, relative abundances of symbiotic bacteria were quantified in mussels from four vent sites, finding site-related differences. We found no within-site differences among specimens collected with or without pressurized recovery.

After pressurized recovery, some mussels were kept alive in pressurized aquaria (IPOCAMP) and subjected to thermal and chemical stress to reproduce an anthropogenic or a natural perturbation of their environment. Variations in the ratio of methane- to sulfur-oxidizing bacteria were observed in response to chemical stress. Notably, for B. azoricus, sulfur-oxidizing bacteria increased when exposed to elevated sulfide levels. For B. puteoserpentis from the deepest site, Snake pit, the increase of abundances of sulfur-oxidizing bacteria was not observed with FISH. However marker gene copy numbers did increase as analyzed by qPCR. B. puteoserpentis exposed to elevated methane levels displayed an increase in methane-oxidizers.

This study markedly improves the procedure for quantifying symbiont abundances in gill tissues and establishes that in vivo analysis of symbiont dynamics in mussel gills is tractable. Results represents a first step toward integrating the dynamics of mussel symbioses into the broader picture of vent ecosystem functioning, and provides a basis for the future evaluation of potential impacts of deep-sea exploitation on endemic symbiotic metazoans. Future work will involve longer exposure experiments, and additional stress sources such as heavy metals and pollutants.

34

A weight of evidence approach for environmental risk assessment of sediment plumes generated on a mine tailings deposit site: implications for deep-sea

mining N.C. Mestre1, T.L. Rocha1, M. Canals2, C. Cardoso1, R. Danovaro3, A. Dell’Anno3, C. Gambi3, F.

Regoli3, A. Sànchez-Vidal2, M. J. Bebianno1

1 Centre for Marine and Environmental Research (CIMA), Universidade do Algarve, Campus Universitário de Gambelas, 8005-139 Faro, Portugal. 2 GRC Geociències Marines, Departament d'Estratigrafia, Paleontologia i Geociències Marines, Facultat de Geologia, Universitat de Barcelona, 08028 Barcelona, Spain. 3 Polytechnic University of Marche, Department of Life and Environmental Sciences, via Brecce Bianche, 60131 Ancona, Italy.

Portman Bay is a heavily contaminated area resulting from decades of metallic mine tailings disposal, and is considered a suitable shallow-water analogue to investigate the potential ecotoxicological impact of deep-sea mining. In the summer of 2014, the mine tailings deposit sediments were artificially disturbed by bottom trawling and originated resuspension plumes. In that frame the environmental risk posed by the resuspension plumes was investigated by a quantitative weight of evidence (WOE) model. Three mussel cages were deployed at 3 sites: off the mine tailings deposit area, on the mine tailings deposit without the influence from the resuspension plumes and under the influence of the artificially generated resuspension plumes. Surface sediment samples were also collected at the same sites for chemical composition analysis and toxicity assessment. Metal concentrations and a battery of biomarkers, oxidative stress (superoxide dismutase - SOD, catalase - CAT, glutathione peroxidases - GPx), metal exposure (metallothionein), biotransformation (glutathione-S-transferases - GST,) and oxidative damage (lipid peroxidation - LPO) were measured in mussel gills, digestive gland and mantle, and all data was integrated in a WOE model. Considering as sediment quality guidelines (SQGs), for the disposal of dredged material at sea, those indicated in Spain Level 1 (the more restrictive), the WOE model indicates that the risk is Slight off the mine tailings deposit, Moderate on the mine tailings deposit without the influence from the resuspension plumes and Major under the influence of the resuspension plumes. The integrated approach used proves to be a useful method to characterize the environmental risk posed by the resuspension of sediments plumes in a mine tailings deposit areas. Considering that Portmán Bay mine tailings deposit is a by-product of sulphide mining, the deep-sea mining of polymetallic sulphides will most likely induce toxicological impact to marine fauna exposed to resuspension plumes of metal loaded sediments.This work was developed under the MIDAS project (managing impacts of deep-sea resource exploitation), funded by the European Commission 7th Framework Programme under the theme “Sustainable management of Europe’s deep sea and sub-seafloor resources” (Grant Agreement 603418).

35

Why we must care about the flexible symbioses of deep-sea animals when addressing the impact of mining

Sébastien Duperron 1,2, Kamil Szafranski 1 Adrien Quiles 1, Bérénice Piquet 1, Marie-Anne Cambon-Bonavita 3, Magali Zbinden 1, Bruce Shillito 1

1 - Sorbonne Universités, Université Pierre et Marie Curie, UMR 7208 BOREA (MNHN, CNRS, UPMC, UCBN, UAG), Paris, France

2 – Institut Universitaire de France, Paris, France

3 – IFREMER, UMR6197 LM2E (Ifremer, CNRS, UBO), Plouzané , France

Animal species living in symbiosis with chemosynthetic bacteria are the dominant fauna occurring in most hydrothermal vents and cold seep ecosystems worldwide. In the Mid-Atlantic ridge vent sites, bathymodiolin mussels and alvinocarid shrimps owe their success to their efficient symbiotic associations with bacteria that fulfill most of their host's nutritional requirements by exploiting various reduced compounds available from the fluids (hydrogen, methane, sulfide, metals...). Once thought to involve a single or two bacterial lineage per host species, recent studies have shown that these symbioses in fact involve a large diversity of bacterial partners, and that these multiple symbioses are highly flexible. Thanks to innovative tools that permit isobaric recovery (PERISCOP) and in vivo experimentation on deep-sea organisms in pressurized vessels (BALIST and IPOCAMP), and to iterative cruises on specific sites, our group can investigate this flexibility. This presentation will summarize major findings that emphasize the importance of flexibility to host phenotypic plasticity (i.e. their ability to cope with variable habitats). In the Mid-Atlantic Ridge, flexibility in terms of symbiont identity, activity and abundance occurs at several scales. The localization and physico-chemical characteristics of sites drive the composition and activity of mussel- and shrimp-associated symbiont communities. Within a given site, different micro-habitats result in different communities associated with a given host. At an individual’s scale, spatio-temporal variability of its habitat alters the abundances of associated bacteria.

These finding confirm that symbiosis is to be taken into account when investigating the impact of human activities on deep-sea vent (and seep) fauna. By addressing the extent of symbioses flexibility through in vivo exposure experiments to different types of substrates (sulfide, methane, hydrogen) or conditions (high temperature or salinity), we can establish the limits that can be tolerated by animal hosts and their symbionts (which together form a holobiont) in the context of natural and human-induced changes. Future experiments are planned to test additional factors (xenobiotics, heavy metals), to perform long-term incubation (days to weeks), and to address impact on other aspects of animal biology of major significance for species survival (reproduction, dispersal). Because symbiont-associated species represent the highest animal biomass at MAR hydrothermal vents and their symbionts are the main and primary producers occurring there, a detailed understanding of the physiology and factors affecting their distribution is crucial for ecosystem understanding and preservation.

36

Analyses of genetic connectivity between populations of deep-sea invertebrate species

Heiko Stuckas1, Sabine Gollner2,3, Terue Cristina Kihara1, Sahar Khodami1, Stefanie Kaiser1, Lena

Menzel1, Annika Janssen1, Pedro Martinez Arbizu1

1Senckenberg Natural History Collections Dresden, Museum of Zoology, Königsbrücker Landstrasse 159, 01109 Dresden, Germany, 2German Center for Marine Biodiversity Research (DZMB),

Senckenberg am Meer, Am Südstrand 44, 26382 Wilhelmshaven, Germany; 3Royal Netherlands Institute for Sea Research (NIOZ), Ecosystem Studies, Korringaweg 7, 4401 NT Yerseke, The

Netherlands

It is expected that deep-sea mining will result in environmental disturbance and loss of biodiversity. Consequently, impact assessments aim to predict the potential for impacted areas to be recolonized by species after mining activities ceased. Genetic analyses of deep sea species in yet undisturbed environments can help predicting the recovery processes after major disturbance events. For instance, population genetic analyses can be performed and discussed in the conceptual framework of genetic connectivity which describes how gene flow affects evolutionary processes within populations. We introduce investigations on different deep-sea invertebrates using partial nucleotide sequences of the cytochrome oxidase I gene (COI; DNA barcoding marker) to explore population genetic patterns in different areas, e.g. the Northern Mid Atlantic Ridge (hydrothermal vents) and the Clarion-Clipperton Fracture Zone (abyssal plain). COI sequences were used to perform phylogenetic analyses, to estimate intraspecific diversity (e.g. haplotype diversity, Hd), to analyze parameters indicating population growth/decline (e.g. Tajima D, Fu’ Fs), and calculate the level of divergence between populations from distant sites (Analysis of Molecular Variance, AMOVA). We found that genetic connectivity is generally high but population demography is different mainly depending on the habitat, i.e., while invertebrates at hydrothermal vents showed expansive populations growth, no such demographic pattern was observed in species of the abyssal plain. We review the recent knowledge on genetic connectivity in deep sea invertebrate species and discuss the potential use of population genetic analyses in deep sea environmental assessments.

37

Key species dispersal and population connectivity at different spatial scales and under different disturbance scenarios at fragmented habitats of the MAR

Ana Colaço ,Maria Rakka, Pedro Ribeiro, Marina Carreiro e Silva; Manuela Juliano

In recent decades, deep-sea ecosystems have been suffering under different anthropogenic pressures such as fishing, oil and gas extraction, climate change and, more recently, the prospect of deep seabed mining. The potential mining areas are located where specialized habitats are often present.

Species can cope with impacts and changes if they are able to maintain their genetic diversity, reproduce, disperse to suitable new habitats, settle and grow to reproduce again.

This process, termed connectivity, has recently been the focus of numerous population genetics studies. There is, however, the need to better understand how physical (ocean currents, habitat suitability) and biological parameters (reproduction mode, larval traits and behaviour) influence population connectivity.

The Azores region hosts several hydrothermal vent fields and seamounts that might host mineral sulphide deposits and cobalt crusts, some of which are of interest to mining companies. These prospective mining sites may potentially be source or sink populations of bathyal fauna, such as cold-water corals, that could be impacted by mining activities. Active hydrothermal vents, which will be either potentially mined or impacted by mining plumes, provide habitat to highly specialised and partly endemic fauna. Identifying larvae sources and sinks for this specialised fauna is essential for spatial planning and strategic regional conservation plans.

Here we present results from a biophysical model of larval dispersal run for two benthic invertebrate species, the vent mussel Bathymodiolus azoricus (Cosel & Comtet, 1999) and the cold-water coral Lophelia pertusa (Linnaeus, 1758). Several scenarios were implemented, based on similar data sets, with changing values for one or two parameters, such as swimming behaviour and larvae density.

The results presented here provide a first estimate of how larvae originating from hydrothermal vents in the Azores might disperse, and quantify the pattern and scale of population connectivity among vents. Population connectivity in B. azoricus seems to be low and mostly restricted to Menez Gwen and Lucky Strike. Low levels of connectivity were also inferred for L. pertusa, where most successful settlers were recruiting onto their natal site. However, results are not conclusive due to several caveats in this exercise that are likely to have influenced our estimates. These arise from current knowledge gaps for some of the parameters used to build the dispersal model.

Perhaps one of the most important gaps concerns the behaviour of deep-sea larvae, of which virtually nothing is known. The vent mussel genus Bathymodiolus is one of the best-studied regarding reproduction and larval traits. Even so, several parameters were inferred from the shallow water mussel genus Mytilus. It is fundamental to increase reproduction and larvae studies for deep-sea species. Informed decisions are good decisions.

38

Faunal colonization processes on organic and inorganic substrata at the Lucky Strike vent field on the Mid-Atlantic Ridge

Jozée Sarrazin1, Daniela Zeppilli1, Ann Vanreusel2, Christoph Plum1, Florence Pradillon1

1 IFREMER, Centre Brest, REM/EEP/LEP, Institut Carnot Ifremer-EDROME, ZI de la pointe du diable, CS10070, F-29280 Plouzané, France.

2 Department of Biology, Marine Biology research group Ghent University, Krijgslaan 281, S8, 9000 Ghent, Belgium.

jozee.sarrazin@ifremer.fr

Despite the fragmented nature of hydrothermal vent fields, nascent vent sites are rapidly colonized by a pool of regional species. While succession of larger hydrothermal fauna is relatively well established, we lack information on the associated meiofauna in particular, on nematodes and copepods. The aim of the present study is to investigate the colonization process of organic and inorganic substrata by faunal assemblages deployed at the Eiffel Tower hydrothermal edifice on the Lucky Strike vent field (MAR), at varying distances from visible hydrothermal activity. Abundance and diversity of colonizing organisms are compared between our different pilot experiments (Cuvelier et al. 2014, Zeppilli et al. 2015, Plum et al. 2016, Zeppilli et al. in preparation).

In total, 46 copepod species were found in our substratum experiment, representing a 4-fold increase in copepod diversity in the LS vent field. Overall, the substrata harboured a very heterogeneous community including not only vent specific species but also uncommon copepod taxa that have not been described from vent sites. The community composition on the substrata changed gradually from active to inactive microhabitats along the gradient of temperature and fluid input, with an increasing heterogeneity and appearance of rare and exclusive species with decreasing fluid input. While showing lowest densities, slates exhibited highest copepod diversity across the activity gradient. High densities of juveniles and larval forms confirmed that copepod communities can be well established in a variety of microhabitats and are capable to spend their whole life cycle under extreme conditions.

For the nematodes, inorganic substrata were preferred near the vents, while organic substrata were rapidly colonized in areas not influenced by vent activity. Nematode females dominated almost at all sites while numerous females at the ovigerous stage and juveniles were reported near the vent emissions, suggesting that nematode populations were well reproducing after 9 months. Our data further suggest that inorganic substrata were preferred in the early succession stages, while organic ones required a longer term to be densely colonized. The type of substratum influenced significantly the composition of colonizing nematodes after 9 months, while after two years the structure of nematode communities was rather influenced by hydrothermal activity.

Macrofaunal results are being compiled and will be presented as well. To date, our result tend to suggest that environmental conditions appear to primarily drive community structure on substrata over time while the type of substrata would be secondary in explaining colonization patterns. In addition, the structure of community was significantly influenced by the deployment duration. Overall, this study significantly contributed to increase our knowledge on LS biodiversity and showed the potential of new hard substrata to increase local recruitment. Our future colonization experiments will be used to test some of the hypotheses that were raised and to propose a colonization model.

39

Reproductive ecology of cold water gorgonian species in the Azores Archipelago: insights and potential impacts upon disturbance

Rakka M. 1*, Sampaio I. 1, Colaço A. 1, Carreiro-Silva M. 1

MARE – Marine and Environmental Sciences Centre Universidade dos Açores, Departamento de Oceanografia e Pescas, 9901-862 Horta, Açores, Portugal

* Correspondence: marianinha.rk@gmail.com

Cold water octocorals, although not reef-building species, form dense aggregations known as “coral gardens” which are classified as Vulnerable Marine Ecosystems (VME) due to their high vulnerability and great importance as habitat-forming communities. The octocorals Callogorgia verticillata, Paracalyptrophora josephinae, Dentomuricea meteor and Viminella flagellum are common cold water coral species in the Azores Archipelago, where they form dense coral gardens between 200 and 1200 meters of depth. The objective of this study is to provide a first complete insight to their reproductive biology and ecology. Specimens, collected during 2010 and 2011 as by-catch from deep long-line fisheries and scientific cruises were histologically processed. All species turned out to be gonochoric with continuous gamete reproduction and overlapping reproductive cycles. Oocyte size frequency distributions were analyzed in order to examine the potential synchronization between sexes and among individuals, as well as to capture and explain patterns of inter-annual variability within the studied populations. Such information is rarely available for CWC species, despite the fact that it is crucial in order to understand basic concepts of their biology and ecology, such as population dynamics and larvae biology. The latter is highly essential in order to predict potential impacts of anthropogenic activities to CWC populations and inform impact management practices.

40

Population connectivity patterns of Bathymodiolus azoricus suggest significant vulnerability to environmental disturbance in NE Atlantic

hydrothermal vents Pedro A. Ribeiro, Govindraj Chavan, Mónica Silva and Ana Colaço

MARE/IMAR Centre and Department of Oceanography and Fisheries of the University of the Azores Rua Professor Doutor Frederico Machado, 9901-862 Horta, Azores, Portugal

Due to the patchy nature of hydrothermal vent ecosystems, recovery of biological communities in areas impacted by SMS mining will greatly rely on the supply of larvae from remote locations. Understanding population connectivity, i.e. the degree to which geographically isolated subpopulations exchange individuals through dispersal, is therefore crucial to establish conservation measures, as it helps to predict ecosystem resilience to disturbance, and can assist in determining the correct placement and extent of marine protected areas. Given that direct measures of dispersal and connectivity in the marine environment are difficult to achieve, indirect methods are often employed, including population genetics. Population genetic structure may provide a long-term average of the degree of population connectivity over evolutionary time scales, although they do not directly translate into demographic connectivity, which typically takes place over inter-annual or inter-generational time scales. In this study, we examined population genetic structure in the charismatic vent mussel Bathymodiolus azoricus inhabiting hydrothermal vents in the Azores. Restriction-site associated DNA (RAD) sequencing was used to genotype thousands of single nucleotide polymorphisms (SNPs) across the genomes of population samples of B. azoricus collected from several sites at the Menez Gwen, Lucky Strike and Rainbow vent fields, at depths between 800 - 2300m. Our analysis inferred moderate population structure among the three vent fields, in particular Menez Gwen and Rainbow, which are the most geographically distant ones. On the other hand, membership coefficients of individuals from Lucky Strike showed significant admixture with both Menez Gwen and Rainbow. Moreover, we found no genetic structure among sites within the Lucky Strike. Our results indicate that larval dispersal among vent fields may be restricted, which may impose limitations on recovery from environmental disturbance. Such limitations do not appear to exist at small spatial scales (i.e. within a particular vent field). In the light of management and conservation, it is however essential to keep in mind that the very low number of migrants required to homogenize genetic variability among subpopulations will almost certainly be insufficient to ensure the recolonization of impacted areas. Therefore, a precautionary approach to genetic estimates of connectivity should be considered.

41

Molecular connectivity within the Clarion Clipperton Zone: a case study using a new nodule-encrusting sponge

Sergi Taboada1, Helena Wiklund1, Gordon LJ Paterson1, Thomas G Dahlgren2,3, Adrian G Glover1

1Department of Life Sciences, Natural History Museum, London, Cromwell Road, SW7 5BD, UK 2Uni Research Miljø, Postboks 7810, N-5020 Bergen, Norway

3Department of Marine Sciences, University of Gothenburg, Sweden

The abyssal area between the Clarion and Clipperton Fracture Zones (CCZ) in the equatorial Pacific, an area of ~6 million km2, is a region of particular interest because of the presence of polymetallic nodules. These nodule fields represent one of the most important areas for deep-sea mining exploration worldwide. Based on modelled data and a precautionary approach, a preliminary network of Areas of Particular Environmental Interestest (APEIs) across the CCZ was established by the International Seabed Authority in 2012 as part of a regional management plan However, very little is known about the fauna of these areas and several important questions remain. With regard connectivity, how connected are the APEIs to the contracted areas, and will the APEIs be effective as marine protected areas?

Recent MIDAS and ABYSSLINE cruises have recovered a large sample set of a new species of nodule-encrusting sponge Hemiasterella sp. nov. belonging to a potentially new family. The species description is underway, but the taxon appears as a good model species to assess molecular connectivity and establish biogeographic patterns from local to large spatial scales within the CCZ for a number of reasons. Hemiasterella sp. nov. is one of the most common encrusting elements of the nodule fauna, probably endemic of this region, highly (or perhaps totally) dependent on nodules. Thus, after mining, populations of this organism are likely to be removed from the directly mined areas as the nodules will be removed. Also, the adults are filter feeders and this makes these organisms potentially susceptible to the impacts of sedimentation. In addition, the species may have limited dispersal capabilities as it has a lecitotrophic larval stage.

Molecular analysis of this species using COI have shown almost no haplotypic variability, which limits the usefulness of this marker in connectivity studies. Here we characterize a range of microsatellite loci using Illumina MiSeq high-throughput DNA sequencing, and test their performance on populations from three different areas within the CCFZ, the APEI-4 and two adjacent planned mined areas (OMS-1 and UK-1 claim areas). Molecular connectivity within populations ranging from a few kilometres to almost 900 kms will be discussed using a total of 170 individuals, a remarkably large sample size for the CCZ. As well as the usefulness of Hemiasterella sp. nov. as a surrogate for other epifauna in molecular connectivity studies, we will also discuss its potential use in habitat suitability modeling.

42

Diversity and distribution patterns of abyssal polynoids (Polychaeta: Polynoidae) across the Clarion Clipperton Fracture Zone (NE Pacific)

Bonifácio, Paulo1; Neal, Lenka2; Menot, Lenaick1

1 REM-EEP-LEP Ifremer. ZI Pointe Du Diable. CS 10070. 29280 Plouzané, France. 2 Department of Life Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK.

In the Clarion Clipperton Fracture Zone, exploration activities and willingness to mine polymetallic nodules have significantly increased over the past five years. The resulting need for environmental management plans at local and regional scales have highlighted the paucity of information on abyssal communities in the region. During the SO239 cruise, four different licensed areas were sampled in the CCFZ, between 4000-5000m depth (BGR, IOM, GSR, Ifremer) as well as an Area of Particular Environmental Interest (APEI#3). Samples were collected using an epibenthic sledge (EBS), a box core (0.25m2) and an ROV. From this cruise, this study aims to describe news species of deep-sea polynoids using morphology complimented with molecular data (COI, 16S and 18S genes. The data can also be used to evaluate monophyly of the subfamily Macellicephalinae and to examine the genetic connectivity for shared morphotypes found in different areas. Preliminary results show 44 morphotypes and ca. 80 molecular operational taxonomic units of Polynoidae with subfamily Macellicephalinae the most abundant and species rich. Until now this study, has found: new species belonging the genera Bathymoorea, Bruunilla, Bathyfauvelia, Macellicephala and Macellicephaloides; evidences of cryptic species distributed in the CCFZ; and five morphotypes that do not fit any of the known genera. Further, one of the most abundant species, Bathyfauvelia sp. A, was found in 4 of the 5 studied areas. Despite the reduced number of haplotypes based on COI (8), there is no evidence for a biogeographic barrier and the connectivity appears to be high between the areas, at least 1000 km apart from each other.

43

Evidence-based management of the Clarion-Clipperton Zone mining frontier requires a new, open-access biodiversity library based on DNA taxonomy

Glover AG1, Wiklund H1, Taboada, S1, Paterson, GLJ1, Dahlgren TG2,3

1Natural History Museum, London, UK.

2Uni Research, Bergen, Norway. 3University of Gothenburg, Gothenburg, Sweden.

* Correspondence: a.glover@nhm.ac.uk

The Clarion-Clipperton Zone (CCZ) of the central Pacific Ocean is currently the most active frontier for deep-sea mineral extraction from international waters. 15 contracts for the exploration of polymetallic nodules from this ~6 million square km region are currently active with the International Seabed Authority, the regulator created by the United Nations Convention on the Law of the Sea. Although no exploitation contracts have yet been approved, the first draft of the guidelines for exploitation has been issued for community consultation and there is a more urgent need than ever for a sound biodiversity reference library, based on open-access DNA taxonomy methods, for the entire region. The lack of this reference library is the single most pressing issue that has prevented what should have been an iterative development of biological knowledge in the region.

We present a solution based on 14 years of experience, including failures, with the KAPLAN, ABYSSLINE and now MIDAS projects. Illustrated by example with original MIDAS data, we propose an openly-available, transparent, traceable DNA taxonomy pipeline, using existing data infrastructures, that is backed up by archived and accessible collections that will ensure a lasting legacy for the MIDAS program.

44

Perspectives on the emerging regulatory regime for deep seabed mining in the Area beyond national jurisdiction

Kristina Gjerde and Aleksandra Gebicka

Wycliffe Management

The outcomes of MIDAS are well-timed to inform the work of the International Seabed Authority (ISA) in its development of regulations for seabed mining in the international seabed Area beyond national boundaries. Under the UN Convention on the Law of the Sea and other relevant instruments, the ISA’s mining regulations are to reflect the best available science, best environmental practices, the precautionary approach, as well as the interests of all humankind, all of which can be supplemented with MIDAS results.

A Working Draft of Exploitation Regulations and Standard Contract Terms focused on procedural and financial issues has been issued for consultation (through 2 November 2016) and draft regulations focused on environmental component are expected to follow in early 2017. This next draft will include details of how environmental impact statements are to be prepared, submitted and assessed; processes for public participation in their review; and requirements for an environmental permit and societal license to proceed to exploitation. Procedures will also be elaborated for site-specific Environmental Management and Monitoring Plans, including emergency orders to alter operations to prevent serious harm, and Closure Plans. The environmental regulations will also place on the ISA the requirement to develop regional-scale Environmental Management Plans (sometimes referred to as Strategic Environment Management Plans) and a Seabed Mining Directorate or Mining Inspectorate.

This presentation will describe the ISA’s progress towards a regulatory framework for seabed mining in the Area, summarise some of the complex issues to come, and highlight some of the key contributions of MIDAS to this process.

45

Mining the deep sea: environmental, political and social challenges

Matthew Gianni

Gianni Consultancy / Deep Sea Conservation Coalition

The International Seabed Authority, the UN body established to regulate deep-sea mining in the international seabed areas of the world’s oceans, has begun a process of drafting regulations for the conduct of commercial deep-sea mining. The challenges associated with regulating deep-sea mining include scientific uncertainty, collecting sufficient baseline information on species and ecosystems, deciding the extent to which adverse environmental impacts must be mitigated or prevented, operationalizing the ecosystem approach and the precautionary approach to prevent damage to the marine environment, and establishing a transparent and enforceable management regime.

The MIDAS Project has produced a considerable amount of information on the potential impacts of deep-seabed mining as well as identified many gaps in the understanding of the potential impacts as well as an understanding of the species, structure and functioning of deep-sea ecosystems overall. The Project has served to provide a stronger scientific basis to inform the policies, positions and recommendations of stakeholders participating in the debate at the ISA and elsewhere in regard to the future regulation of seabed mining. The presentation will outline a set of conclusions and recommendations put forward by a number of NGOs based in Europe and elsewhere drawing on the findings of te MIDAS Project.

46

Reconciling precaution and urgency via an adaptive approach to deep sea mining

Sybille van den Hove & Rob Tinch

Median Sustainability SL

For deep-sea mining, the dominant policy questions are whether, why, where and how to authorise or even encourage DSM, and the policies that are needed to ensure that it contributes as much as possible to fulfilling societal needs, including economic development, in the context of a broader societal vision of Sustainability as articulated in the Sustainable Development Goals. There are issues here associated with timing and intra- and inter-generational sharing of resources. The benefits of waiting and learning, which would correspond to an entirely precautionary approach, include a better understanding, reduced risks, better technology, and potentially lower costs of operation, yet it requires investment in R&D. But this is harder to reconcile with a sense of urgency conveyed by several stakeholders who stress the needs/demand for the resources and the geopolitical/strategic 'imperatives'. One way forward is to target both the scale and the timing of action through a staged approach where we decide to exploit resources with lower risks in a limited number of smaller sites, with a focus on a strong research comopent to learn as we go, subsequently and iteratively deciding whether or not to continue exploiting and to exploit in other areas, deliberately opting for an adaptive strategy. This paper explores the reasoning behind this approach, the associated behavioural incentives for different actors, and the policy/governance needs of implementing it.

47

Evaluating the transparency of the International Seabed Authority Jeff Ardron

National Oceanography Centre, Southamtpon, SO14 3ZH, UK

To assess the current practices of the International Seabed Authority (ISA) with regard to transparency and public participation, WG9 used an earlier assessment of Regional Fisheries Management Organisations (RFMOs) as a reference point for recognised good practices. In the case of the ISA, however, we found that while it exhibits some good transparency practices, it generally scores much lower than high seas fisheries management bodies. Across the three evaluation categories, concerning availability of information, participation in decision-making, and access to outcomes, the ISA’s overall score was found to be 44%, as compared to 77% for the RFMOs. The current practices of RFMOs may therefore serve as examples of how specific operations of the ISA could be improved. It is suggested that the ISA needs to develop concrete policies concerning transparency, including: to presume that information is non-confidential unless otherwise determined; to make mining contracts publicly available; to allow observer access to pre-determined portions of the Legal and Technical Commission, and Finance Committee meetings; and, to publish annual reports of the Contractors’ activities, including compliance in seabed exploration and exploitation operations and their associated environmental impacts.

48

Strategic conservation planning for the Area with a focus on Areas of Particular Environmental Interest (the SEMPIA process)

David Johnson

Seascape Consultants Ltd, UK

A significant spin off from MIDAS is the initiation of a process to determine a Strategic Environmental Management Plan in the Atlantic (SEMPIA). Strategic conservation planning in Area Beyond National Jurisdiction has been advocated in the context of High Seas governance (e.g. Ban et al., 2013; Gjerde et al., 2016), and more specifically for the Area by the UN General Assembly.

The Atlantic initiative is modeled on the process that resulted in endorsement and adoption by the International Seabed Authority of an Environmental Management Plan for the Clarion-Clipperton Zone (CCZ-EMP) in the Pacific and informed by the Dinard Workshop in 2010 (ISA Technical Study No. 9). Rather than manganese nodule deposits (the focus of the CCZ-EMP) the challenge for the Atlantic is socially and environmentally responsible exploitation of SMS deposits.

The first meeting of SEMPIA, held in Horta Azores in June 2015, was informed by a data report (Morato et al., 2015). It undertook a ‘scoping exercise’ to identify significant issues and conceived a concept of ‘banded’ Areas of Particular Environmental Interest (APEIs). During 2016 efforts to build on this meeting have considered risks to deep-sea habitats, active hydrothermal vents as ‘Vulnerable Marine Ecosystems’ and strengthening the scientific case for different APEI options.

A second meeting of SEMPIA will take place in November 2016 with the objective of agreeing design criteria (i.e. spacing, dimensions and coverage of APEIs). SEMPIA II should also give consideration to climate change implications and ecosystem services. A draft SEMP proposal is then envisaged for further consideration by the International Seabed Authority and key stakeholders in 2017/18.

The SEMPIA process has wider policy implications at a time when the Preparatory Committee for a new legally binding Implementing Agreement for Biodiversity Beyond National Jurisdiction is preparing substantive recommendations in advance of the 72nd session of UNGA (2018) when a decision will be made on the convening and starting date for an Intergovernmental Conference (Long and Rodriguez Chaves, 2015). At the same time the Sustainable Development Goal agenda is underway and the Convention on Biological Diversity has commitments within its Aichi Targets to secure marine protected area coverage to include ‘other effective conservation measures’ by 2020. Ultimately SEMPIA should provide a template for exploitation of SMS deposits in other sea basins.

Ban., N., Bax, N., Gjerde, K., Devilliers, R., Dunn, D., Dunstan, P., et al. (2013) Systematic Conservation Planning: a better recipe for managing the high seas biodiversity conservatin and sustainable use. Conservation Letters X (2013) 1-14. Gjerde, K., Nordtvedt Reeve, L., Harden-Davies, H., Ardron, J., Doln, R., Durussel, C. et al. (2016) Protecting Earth’s last conservation frontier: scientific, management and legal priorities for MPAs beyond national boundaries. Aquatic Conserv: Mar. Freshw. Ecosyst. 26 (Suppl. 2): 45-60 (2016) Long, R. and Rodriguez Chaves, M. (2015) Anatomy of a new international instrument for marine biodiversity beyond national jurisdiction: frst impressions of the preparatory process. Environmental Liability, Law, Policy and Practice. Volume 23(6): 213-229 Morato, T., Cleary, J., Taranto, G., Vandeperre, F., Pham, C., Dunn, D., Colaco, Halpin, P. (2015) Data report: Towards development of a Strategic Environmental Management Plan for deep seabed mineral exploitation in the Atlantic Basin. IMAR & MGEL, Horta, Portugal 103 pp

49

Impact of mining activities on virus-prokaryote interactions in benthic abyssal ecosystems of the Clarion Clipperton Fracture Zone (Pacific Ocean)

Antonio Dell’Anno1*, Cinzia Corinaldesi2, Elisabetta Manea1, Michael Tangherlini1, Cristina Gambi1, Pedro Martinez Arbizu3, Roberto Danovaro1,4

1CoNISMa-Ancona, Polytechnic University of Marche, Italy 2Dipartimento di Scienze e Ingegneria della Materia, dell’Ambiente ed Urbanistica, Polytechnic

University of Marche, Italy 3Deutsches Zentrum für Marine Biodiversitätsforschung Senckenberg am Meer Südstrand, Germany

4Stazione Zoologica Anton Dohrn, Italy

*Speaker: Antonio Dell’Anno (a.dellanno@univpm.it)

Viruses are the most abundant biological entities in the world’s oceans and they play a crucial role in global biogeochemical cycles. In deep-sea ecosystems, prokaryotes drive major nutrient cycles, and viruses are largely responsible for their mortality, thereby exerting important controls on microbial dynamics. However, how virus-host interactions respond to anthropogenic impacts in the deep ocean interior is completely unknown. The Clarion Clipperton Fracture Zone in the abyssal Pacific Ocean represents the largest reservoir of high-grade polymetallic nodules, thus representing a key area for future commercial exploitation of such mineral resources. To improve our knowledge on the potential impact of deep-sea mining on virus-host interactions and prokaryotic biodiversity, we collected sediment samples on board of the R/V Sonne (March-April 2015) in four exclusive economic zones of the Clarion Clipperton Fracture Zone. Sampling strategy included the collection of sediment samples in areas subjected to simulated mining activities carried out at different time scales (from days to several years) by means of push-corers mounted on ROV and in un-disturbed areas through multiple-corer deployments. Here we show results on the effects of simulated mining activities on virus-host interactions and prokaryotic diversity in order to provide new insights on the potential consequences of deep-sea mining on the biodiversity and functioning of the benthic microbial food webs.

50

First insight on mussel’s response to fluid physico-chemical changes from a modelling approach

Bérengère Husson, Pierre-Marie Sarradin, Alain Menesguen, Karline Soetaert, Dick Van Oevelen, Jozée Sarrazin

Nearly 40 years of research on hydrothermal vent ecosystems have led to a better understanding of species distribution and the mechanisms allowing their survival in these harsh environments. However, questions still remain on the processes and dynamics that drive the response of species to the highly variable spatial and temporal changes in fluid temperature and composition. Modeling is a widely used tool in marine biology to integrate data and test hypotheses on unknown processes, and is now an emerging tool in hydrothermal vent ecosystem studies.

This study aims at better understanding the dynamics of mussel assemblages colonizing the Eiffel Tower edifice (Lucky Strike vent field, Mid-Atlantic ridge) using a modelling approach. The edifice is dominated by the mussel Bathymodiolus azoricus, which constitutes nearly 90% of the biomass. Existing data and models on this engineer specieswere integrated in a new model structure taking into account their chemical environment. The model predicts the growth and survival of mussels in a given chemical context and brings insights on their dynamics on the edifice, and particularly, on their size segregation.

In the context of future deep sea mining, upcoming data on mussel response can be implemented in this model, thus bringing insights on the potential impacts of sulphide-rich sediment deposition on mussel’s survival. On the long term, the model will be completed by the addition of other faunal compartments and coupled to a biogeochemical model, resulting in an ecosystemic model that can be used to fully understand the functioning and dynamics of Eiffel Tower faunal communities.

51

Effects of deep-sea mining on the antioxidant defense system of the cold-water coral Dentomuricea aff. meteor

Inês Martins, J. Goulart, V. Riou, J. Raimundo, M. Caetano, A. Colaço, R. Bettencourt, M. Carreiro-Silva

MARE – Marine and Environmental Sciences Centre, 9901-862 Horta Portugal

IMAR/DOP 9901-862 Horta, Portugal

Benthic suspension feeders, such as corals, are likely to be greatly impacted by sediment plumes generated during mining activities for deep-sea mineral resource extraction. Exposure to suspended sediments can mechanically damage corals by smothering and clogging their tissues, and can also contain toxic substances that affect coral physiological processes. In an aquaria-based experiment we simulated the effects of Polymetallic Sulfide (PMS) plumes, generated during mining activities in a hydrothermal vent field, on the physiology of the cold-water octocoral Dentomuricea aff. meteor. Corals were collected from the summit of Condor Seamount at depths between 185-210 m. Coral fragments were maintained in 10-L aquaria and exposed to three experimental treatments for a period of four weeks: (1) a control treatment with filtered seawater; (2) exposure to suspended SMS particles (25 mg/L; 0.5-0.7 µm); (3) exposure to suspended inert quartz particles (25 mg/L; 0.5-0.7 µm). The two particle treatments were designed to distinguish between potential mechanical and toxicological effects of mining sediments. PMS particles were obtained by grinding sedimentary rocks collected at the hydrothermal vent field Lucky Strike, and particle size matched the range expected by Seafloor Mining Tools excavation and by dewatering processes, according to the IHC Mining B.V Company. During the experiment period, diffusive gradients in thin films (DGT’s) were used to monitoring the bioavailable labile metal fraction in the different exposure treatments. The antioxidant enzymatic activities of superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST), heat-shock protein HSP70 and lipid peroxidation were examined in coral fragment tissues to evaluate tissue metabolic specificities under PMS exposure. Our results showed that smothering and clogging of Dentomuricea aff. meteor tissues together with trace metals desorption, induces cellular antioxidant alarm and leads to massive mortality after long term PMS exposure.

52

Responses of nematodes to increased copper toxicity, tailings exposure and sediment deposition from in-situ and laboratory experiments

Mevenkamp Lisa1, Brown Alastair2, Guilini Katja1, Lins Lidia1, Moodley Leon3, Stratmann Tanja4,

Sweetman Andrew3, van Oevelen Dick4, Westerlund Stig3, Vanreusel Ann1

1 Marine Biology Research Group, Ghent University, Krijgslaan, Ghent, Belgium Lisa.Mevenkamp@ugent.be

2 University of Southampton, Ocean and Earth Science, National Oceanography Centre Southampton, European Way, Southampton, SO14 3ZH, UK

3 International Research Institute of Stavanger (IRIS), Randaberg, Norway 4 Department of Ecosystem Studies, NIOZ Royal Netherlands Institute for Sea Research, Korringaweg

7, 4401 NT Yerseke, The Netherlands

The impacts of polymetallic nodule extraction on marine benthic organisms are expected to be very variable in nature and intensity, though threshold values for the survival and recovery of deep-sea organisms are largely unquantified. Direct impacts related to the nodule removal include sediment compression and sediment redistribution while the release of toxic amounts of heavy metals or burial with suspended sediments or mine tailings are indirect impacts from the mining operation. Additionally, ore extraction from the nodules may result in the production of substantial amounts of tailings and deposition at the removal site is not implausible. To assess short to medium term impacts of these different types of disturbances we focussed our research on the response of an ubiquitous and very abundant taxon, the nematodes. This presentation provides an overview of the results of lab experiments and in-situ experiments performed during the MIDAS project that were designed to investigate the sensitivity of nematodes to copper toxicity and sediment deposition disturbances.

In an experiment assessing lethal concentrations of Cu2+ of the nematode Halomonhystera disjuncta, a close shallow water relative of the deep-sea species H. hermesi, was exposed to different Cu2+ concentrations under atmospheric and increased hydrostatic pressure at different temperatures. The results of these toxicity tests suggest that copper sensitivity differs under deep-sea conditions (low temperature, high pressure) from shallow water conditions (high temperature, low pressure) with higher tolerance at low temperatures but increased sensitivity with increased pressure suggesting that shallow water species are not a good proxy to test abyssal response. During RV “Sonne” cruise 242-2, we deployed 6 corrals and exposed the in-situ sediment fauna to artificial sediment spiked with different copper concentrations. Treatments included a control without artificial sediment, a control with uncontaminated sediment and four different copper concentrations (1, 5, 10, and 20 mg Cu l-1). After 96 hours of incubation, sediment samples for meiofauna analyses were taken. Only slightly decreased meiofauna abundances were found in the highest Cu contamination treatment while sediment analysis showed a very high copper concentration in the natural sediments. To address the issue of sediment redistribution and potential impacts of tailings placements on deep-sea fauna, two other experiments were conducted, one in controlled lab conditions (with sediment from 200m) and one in situ (4200m). In both experiments, the benthic fauna was exposed to iron ore tailings (lab experiments) and crushed nodule substrate (in-situ experiment), and meiofauna densities were recorded after an incubation time of 11 days. The lab experiment revealed that differences in sediment characteristics (grain size, organic carbon content) and reduced oxygen penetration resulted in an increased mortality of nematodes in the added substrate. Only preliminary results can be given for the in-situ experiment.

53

Impact of deep-sea mining on benthic food webs with special emphasis on megafauna

Tanja Stratmann1, Ilja Voorsmit2, Andrew K. Sweetman3, Lisa Mevenkamp4, Ann Vanreusel4, Andrey Gebruk5, Alastair Brown6, Autun Purser7, Yann Marcon7, Dick van Oevelen1

1Royal NIOZ, Yerseke, The Netherlands; 2University of Groningen, Groningen, The Netherlands; 3Heriot-Watt University, Edinburgh, UK, 4University of Ghent, Ghent, Belgium; 5P.P. Shirshov Institute

of Oceanology, Moscow, Russia;6University of Southampton, Southampton, UK; 7Alfred Wegener Institute, Bremerhaven, Germany

Deep-sea mining of manganese nodules will severely impact abyssal ecosystems, including the removal of fauna attached to nodules and infauna in the upper sediment layers. However, to make an accurate assessment of the influence of mining on ecosystem functioning and carbon flow partitioning it is important to define a baseline for comparison.

First, we developed global maps of sediment community oxygen consumption (SCOC) and benthic biomass using random forest predictions. These maps were combined with a database on biomass-specific faunal respiration rates to arrive at the first global estimates of bacterial, meiofaunal, macrofaunal and megafaunal respiration in the seafloor. Based on these maps we estimated for the abyssal plains that bacteria contributed 76%, meiofauna 17%, macrofauna 7% and megafauna <1% to the total SCOC.

As a verification step of these global maps, we contrasted this global baseline with a detailed assessment of the role of holothurians in carbon cycling of the abyssal plains of the Peru Basin. Based on photos from the AWI ocean floor observatory system (OFOS) we identified 23 different holothurian morphotypes and determined their abundance in the DISCOL area in disturbed, undisturbed and reference areas. Benthic incubation chamber (BICs) were deployed during SONNE cruise SO242-2 to determine individual respiration rates of holothurians. These in-situ data were used to calculate the total holothurian respiration. Holothurians respired 19.43 mmol C ha-1 d-1 in this area, which was 0.78% of the community respiration.

Finally, we performed small-scale in situ pulse-chase tracer experiments in the DISCOL area (DEA) to compare the carbon flow through the benthic food web in disturbed and reference areas to constrain food web models for these areas. Preliminary results indicate that there is no statistical difference between disturbed and reference sites in uptake of carbon by bacteria, nematodes and holothurians

54

Bacteria are key players in the short-term degradation of phytodetritus in abyssal CCZ sediments

Sweetman, A.K.1, Smith, C.R.2, Maillot, B.3, Schulse, C.4, and Church, M.J.3

1The Lyell Centre for Earth and Marine Science and Technology, Heriot-Watt University, Edinburgh, UK A.Sweetman@hw.ac.uk

2Department of Oceanography, University of Hawaii at Manoa, Honolulu, USA 3Center for Microbial Oceanography and Education (CMORE), University of Hawaii at Manoa,

Honolulu, USA 4Joint Genome Institute, Walnut Creek, USA

The abyssal zone (3000-6000m) is truly vast, covering 54% of the Earth´s surface. The vast majority of the abyssal seafloor relies on exported labile components of phytodetritus from the euphotic zone for food. Whilst numerous studies have explored the importance of phytodetritus to deep-sea organism diets through gut pigment, fatty-acid and stable isotope analyses, it is only with the development of stable isotope pulse-chase techniques that researchers have been able to identify the initial responders to phytodetritus deposition events, and quantify rates of phytodetrital carbon and nitrogen uptake by the benthic community. In the only study so far carried out at abyssal depths that assessed the response of bacteria and macrofauna to phytodetritus, Witte et al. (2003) found that macrofauna were the dominant group involved in the initial degradation of phytodetritus at the eutrophic Porcupine Abyssal Plain (PAP). Here, we report on results from 10 in-situ benthic isotope tracer experiments carried out under mesotrophic abyssal settings. We show that bacteria, not macrofauna, are responsible for most C-turnover in sediments in the manganese nodule province of the Clarion Clipperton Zone (CCZ). We also show that these observations are consistent over regional scales. We noted no significant shift in bacterial diversity when sediments exposed to fresh phytodetritus, suggesting that shifts in bacterial diversity do not happen immediately (i.e., < 36hrs) upon exposure to food-input in abyssal sediments. Overall, the results from this case study reveal the key role of bacteria in the initial degradation of fresh phytodetritus at the seafloor in abyssal mesotrophic environments, and emphasize the differences that can exist in terms of short-term C-cycling processes in different abyssal environments (e.g., mesotrophic vs. eutrophic).

Witte, U. et al. (2003) In situ experimental evidence of the fate of a phytodetritus pulse at the abyssal sea floor. Nature, vol. 424, p.763–765.

55

The metal-bearing mine tailings deposit from Portman Bay: a multi-proxy characterisation

M. Canals*, M. Cerda-Domenech, A. Sanchez-Vidal , J. Frigola, E. Barriuso and T. Baraza

GRC Geociències Marines, Department of Earth and Ocean Dynamics, University of Barcelona, Spain

* miquelcanals@ub.edu

Fifty-two short multicores up to 45 cm long and six gravity cores up to 3 m long from the shallow water, metal-bearing mine tailings deposit of Portman Bay have been used to characterize its elemental composition and internal 3D structure as shown by density changes, and to cross-correlate the most relevant properties. The main techniques applied were non-destructive and included X-ray fluorescence core scanning with an Avaatech XRF core scanner and X-ray computed tomography with a micro-CT MultiTom Core CT system, both installed at the premises of the University of Barcelona. In addition, selected samples were analyzed by X-ray fluorescence spectrometry to obtain total metal concentrations and by laser diffraction to get the particle size distribution. Results show that the deposit is enriched in Fe, Zn, Pb and the metalloid As. They also allow distinguishing a sandy upper unit of variable thickness (usually some tens of cm) made of rather homogeneous blackish materials, with signs of bioturbation and low, although highly variable, radio-density values. The unit below consists of homogenous dark greenish grey sediments, with no signs of bioturbation, smaller amounts of sand and rather constant radio-density values. The upper unit is interpreted as the result of the reworking of the top of the mine tailings deposit by oceanographic processes, whereas the lower unit is assumed to correspond to the bulk of the deposit. The two units show distinct elemental composition, with the highest densities corresponding to the intervals with higher metal contents. There is an inverse correlation between Fe and sand contents, which shift sharply at the boundary between the two units. Total metal concentrations for the upper half meter of the deposit yielded the following results: Fe = 85-300 g kg-1, Zn = 3-7 g kg-1, Pb = 1-6 g kg-1 and As = 0.2-0.8 g kg-1. The high concentrations of Fe have stimulated some studies to assess the viability of its commercial extraction. Further research should allow analysing the composition and internal structure of the deeper layers of the deposit, which total thickness has been estimated at 13 m to 24 m below the modern shoreline according to various sources. Future research plans foresee the extraction of long cores reaching the base of the deposit, which should allow an improved characterisation before remediation plans in Portman Bay are eventually implemented.

56

Recovery of benthic ecosystem after a submarine eruption in the northeast Atlantic Ocean

Dell’Anno A.1*, Canals M.2, Corinaldesi C.3, Michael Tangherlini1, Cristina Gambi1, Lastras G.2, Amblas D.2, Sànchez-Vidal A.2, Frigola J.2, Calafat A.M.2, Pedrosa R.2, Rivera J.4, Rayo X.3, Danovaro

R.1,5

1CoNISMa-Ancona, Polytechnic University of Marche, Italy 2Department of Earth and Ocean Dynamics, University of Barcelona, Spain

3Dipartimento di Scienze e Ingegneria della Materia, dell’Ambiente ed Urbanistica, Polytechnic University of Marche, Italy

4Instituto Español de Oceanografía, Spain 5Stazione Zoologica Anton Dohrn, Italy

a.dellanno@univpm.it

In the framework of the MIDAS project, we investigated the recovery of benthic ecosystem after a submarine eruption occurred in the northeast Atlantic Ocean in 2011. Here we show, that newly formed volcanic rocks following the submarine volcano eruption are colonised by microbial mats characterized by white and long filaments which favour the establishment of a complex food web. Metagenetic and metagenomic analyses revealed the presence of highly diversified assemblages potentially represented by chemosynthetic and heterotrophic components. Our analyses also suggest that microbial mats colonizing volcanic rocks are characterized by a wide spectrum of metabolic pathways for the exploitation of CO2 coupled with sulphur oxidation. Overall, findings reported here provide new information for expanding our understanding of biological processes enabling the recolonization of impacted seafloor.

57

Nematode assemblages affected by historical mine tailing discharge in Portman Bay (Southern Spain)

Cristina Gambi1, Antonio Dell’Anno1,*, Cinzia Corinaldesi1, Elisabetta Manea1, Michael Tangherlini1, Anna Sanchez Vidal2, Miquel Canals2, Roberto Danovaro1,3

1CoNISMa-Ancona, Polytechnic University of Marche (Italy)

2University of Barcelona (Spain)

3Stazione Zoologica Anton Dohrn (Italy)

c.gambi@univpm.it

Portman Bay (Southern Spain, Western Mediterranean) likely represents one of the most chronically contaminated ecosystem by mining-related activities of the entire Mediterranean basin. Indeed, huge amounts of tailings (>25 millions of cubic meters) deriving from mineral extraction activities have been discharged directly into Portman Bay from 1958 to 1990. As such, this ecosystem can represent a model to investigate the potential impact deriving from mining activities on benthic fauna, both in terms of effect due to mining by-products, and/or mechanical disturbance and the consequent re-deposition of buried contaminants. Sediment samples were collected, in joint collaboration with the University of Barcelona in August 2014, before and after experimental trawling conducted both inside and outside the Portman bay, and in a non-trawled area used as a control. We investigated the impact of mining activity on the taxonomic and trophic diversity and life strategy of nematode assemblages (the dominant component of meiofauna) i) in relation with putative gradients of contamination from the coast to offshore, and ii) their short-term responses after disturbance events (substrate removal and re-deposition) induced by trawling activities. Here, we present results on changes of nematode assemblages along the gradient of contamination and their responses to simulated disturbance events.

58

Resilience of benthic deep-sea fauna to mineral mining activities

Sabine Gollner a, b, Stefanie Kaisera, Lena Menzela, Pedro Martinez Arbizua and contributing authors of MIDAS D6.6.

aGerman Centre for Marine Biodiversity Research, Senckenberg am Meer, Wilhelmshaven, Germany

bRoyal Netherlands Institute for Sea Research, Ocean Systems (OCS), t’Horntje (Texel), Netherlands

Contributing authors (in alphabethical order): Alastair Brown (USou), Miquel Canals (UB), Ana Colaço (IMAR), Daphne Cuvelier (IMAR), Jennifer M. Durden (NOC), Andy Gebruk (SIO), Matthias Haeckel (GEOMAR), Daniel O.B. Jones (NOC), Lenaick Menot (IFREMER), Nelia C. Mestre (UALG), Lisa Mevenkamp (UGent), Telmo Morato (UAC), Dick van Oevelen (NIOZ), Christopher K. Pham (IMAR), Autun Purser (AWI), Anna Sanchez-Vidal (UB), Ann Vanreusel (UGent), Annemiek Vink (BGR)

With increasing demand for mineral resources, extraction of polymetallic sulphides at hydrothermal vents, cobalt-rich crusts on seamounts, and polymetallic nodules on abyssal plains may become reality in the near future. We identify threats and disturbances created by mining and estimate resilience (i.e. the ability of a system to maintain structure and function, in the face of internal change and external disturbances) and related concepts (resistance, recovery, and reversibility) of these ecosystems in regard to deep-sea resource exploitation. We find that resistance (i.e. the natural ability to remain unaffected by a force) will mainly apply to species’ responses to the impact of (potentially toxic) particle plumes, while fauna in the area of immediate impact may be killed due to substrate removal and alteration of the habitat. We perform a meta-analysis on density and diversity recovery rates after disturbances most similar to mining i.e., volcanic eruptions at hydrothermal vents, seamount fisheries, and human-induced disturbance events that mimic mining of polymetallic nodules. We find a huge variation of recovery rates, between and within ecosystems, as well across taxa, size and mobility of animals (Figure 1). While densities and diversity of certain taxa can recover to pre-disturbance or control conditions or even exceed those within a few years, community composition across all ecosystems remains different even after decades. We evaluate reversibility of community changes following deep-sea resource exploitation and find that the loss or change of hard substrate composition may cause substantial community changes persisting over geological time-scales at directly mined sites.

Figure 1. Mean relative recovery (%) of faunal density and diversity after time of disturbance (in years) at seamounts, active vents, vent periphery, and nodule fields. No recovery data were available for inactive vents.

59

Feasibility and possibility for restoration and mitigation actions in ecosystems impacted by mining

Daphne Cuvelier1, Boris Dzon2, Sabine Gollner4, Dan Jones3, Pedro Martínez Arbizu4, Stefanie Kaiser4, Lena Menzel4, Nelia Mestre5, Telmo Morato1, Christopher Pham1, Florence Pradillon6, Autun

Purser7, Uwe Raschka4, Jozée Sarrazin6, Erik Simon-Lledo3, Ian Stewart8, Heiko Stuckas4, Andy Sweetman9, Ana Colaço1

1 IMAR (Instituto do MAR)/MARE (Marine and Environmental Sciences Centre)

2 IHC MTI B.V., 3 NERC-NOC, 4 Senckenberg, 5 CIMA, 6 Ifremer, 7 AWI, 8 Fugro, 9 IRIS

Mining impacts will affect local populations to different degrees. Impacts range from habitat and energy source removal to pollution and smaller-scale alterations in local habitats which, depending on the degree of disturbance, will lead to extinction of local communities. Mitigation and restoration of mining operations needs to be considered to make sure that points beyond which ecosystem or community recovery is impossible are avoided. No single action will suffice to allow an ecosystems to recover, instead combined mitigation/restoration actions need to be considered. Such sets of combined mitigation/restoration actions should facilitate and eventually accelerate the rates of recovery of biodiversity and function of deep-sea ecosystems and thus will depend on the specific characteristics of the different mining habitats and the resources hosted (polymetallic nodules, ferromanganese cobalt rich crusts, sulphides, gas hydrates).

Within MIDAS, a wide range of mitigation and restoration actions for all ecosystems at risks were addressed. These actions range from the deployment of artificial substrates to enhance faunal colonisation and survival to habitat recreation, artificial eutrophication, but also include spatial and temporal management of mining operations, as well clever mining machine construction to minimise for instance plume size on the sea floor, toxicity of the return plume and sediment compression. Possible positive and negative effects of these actions on the ecosystems are discussed, as well as an assessment of to which extent such knowledge is available, ecologically feasible and how the possible outcomes might contribute to ecosystem recovery.

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Megabenthic community structure within and surrounding the DISCOL Experimental Area 26 years after simulated manganese nodule mining

disturbance. Yann Marcon1,2, Autun Purser1, Felix Janssen1,3, Lidia Lins4, Alastair Brown5, Antje Boetius1,3

1 Alfred Wegener Institute Helmholtz-Center for Polar and Marine Research, Bremerhaven, Germany

2 MARUM Center for Marine Environmental Sciences, Bremen, Germany 3 Max Planck Institute for Marine Microbiology, Bremen, Germany

4 Ghent University, Ghent, Belgium 5 National Oceanography Centre, Southampton, UK

Efforts to satisfy the current need for many high technology elements, such as copper, nickel and yttrium from land-based sources are growing. Potential future sources of some of these elements include the deep sea manganese nodule fields of the Pacific, Atlantic, and Indian oceans. Large swathes of deep-sea seafloor are covered with high densities of 5 – 25 cm diameter nodules – agglomerations of manganese, iron, cobalt, copper, and other metals. In the 1980's these manganese fields were first seriously considered as mining targets, and the ''DISturbance and reCOLonization (DISCOL) experiment was started in the tropical Southeast Pacific, to simulate the likely environmental impacts of mining. In September 1989, 'RV SONNE', used a plough device to disturb the top sediment and to remove manganese nodules from the seafloor surface by burying them below the surface. 78 plough tracks of 8 – 16m width were made across a 10.8 km diameter circular area centered at 7°04.4´S 88°27.6´W. Megafauna abundances were assessed prior and post ploughing, both within the disturbed area and at reference stations 6 km from the disturbed area. This disturbance and removal of nodules (and therefore hard substrate) is likely to represents the most significant benthic impact experiment carried out at the deep-sea floor to date.

Research cruises in the 1990s investigated the short-term temporal impact ploughing had on the faunal community in the DISCOL area. Cruises conducted 3 and 7 years after disturbance showed that megafauna communities within ploughed areas remained quite distinct from those observed pre-disturbance or in the reference areas.

In 2016 the 'RV SONNE' revisited the DISCOL site, as part of the 'JPI Oceans' programme ‘Ecological Aspects of Deep-Sea Mining.’ Here we report the current megafauna community structures observed during expedition SO242-2 within the DISCOL area. 1500 images covering an area of approximately 7400 m² have been analysed. Results show that communities in and near disturbance tracks differ from those found in the undisturbed areas and that the removal of hard substrates from the sediment surface particularly affects the recovery of sessile communities. Over the past 26 years many taxa did not recover, indicating that the experimental disturbances had a long-term effect on seafloor fauna, despite the use of modest disturbance gear compared to mining equipment.

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Meiofauna response to physical disturbance at the DEA: the importance of scale to identify long-term effects

Freija Hauquier1, Lisa Mevenkamp1, Egho Great1, Tania Nara Bezerra1, Lidia Lins1, Felix Janssen2, Tobias Vonnahme2, Antje Boetius2, Ann Vanreusel1

1 Marine Biology Research Group, Ghent University, Ghent, Belgium

2 HGF-MPG Group for Deep Sea Ecology and Technology, Max Planck Institute Bremen and Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany

Polymetallic nodules in deep-sea habitats of the Pacific Ocean will be subject to commercial exploitation in the near future but the potential effects of such mining activities on benthic life are difficult to assess. Here we present results from a recent revisit onboard RV SONNE (leg SO242/2) to the site of the “DISturbance and reCOLonization experiment” (DISCOL), a large scale benthic impact study initiated in 1989 in a polymetallic nodule area in the Peru Basin (tropical south-eastern Pacific). The area was artificially disturbed by a plow harrow to simulate manganese nodule extraction. In 2015, Meiofauna samples were collected and analysed at two different spatial scales in the framework of the JPI Oceans' programme ‘Ecological Aspects of Deep-Sea Mining’ to study the response and recovery rate of benthic faunal communities.

At a macroscale, meiofauna densities and community composition were compared between two stations within the DISCOL experimental area (DEA) and three undisturbed reference stations. No long-term disturbance effects could be identified, most likely because high sediment heterogeneity in the disturbed and reference sites resulted in large variation in meiofauna communities.

However, additional ROV push core sampling at selected microhabitats within the disturbance tracks (white patches, ripple crests and ripple valleys) revealed significant differences at a microscale for two out of three tracks. Meiofauna abundances were significantly reduced at all sites compared to outside track control samples with the exception of ripple valleys. Lowest densities were found at the white spot habitats where disturbances in 1989 exposed deeper sediment layers and where lowest pigment and organic matter contents were found. The study demonstrates that physical disturbances as they will be associated with mining will most likely result in long-term impacts on meiofauna communities in nodule areas. However, the results also show that detailed investigations at small spatial scales may be required to discriminate disturbance effects on meiofauna communities from natural variability.

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Effects of simulated deep-sea mining impacts on microbial communities and functions in the DISCOL experimental area.

Tobias Vonnahme, Felix Janssen, Massimiliano Molari, Frank Wenzhöfer, Antje Boetius

1 HGF-MPG Group for Deep Sea Ecology and Technology at Alfred Wegener Institute, Bremerhaven, Germany and Max Planck Institute for marine Microbiology, Bremen, Germany

This study investigates potential impacts connected to the removal of manganese nodules on deep-sea sediment biogeochemistry and benthic microbial communities. The study site is located in the DISCOL Experimental Area (DEA) in the Peru Basin where a large scale disturbance experiment has been carried out in 1989. Investigations were performed during RV SONNE cruise SO242/2 in Sep. 2015 in the framework of the JPI Oceans programme ‘Ecological Aspects of deep sea mining’. The focus of the work presented here is on effects on the community structure, activity, and functions of benthic microorganisms. Sediment cores and manganese nodules were sampled in different disturbed and undisturbed areas. Overall, four microhabitats within the initial DISCOL disturbance tracks, a recent disturbance track created by an epibenthic sledge, and reference areas outside the DEA were investigated. Samples for laboratory incubations and analyses were taken with ROV and multicorer while fluxes were studied in situ with autonomous benthic chamber and micro profiler systems. Sediments were characterized by their colour, phytopigments, particulate carbon and nitrogen contents. The microbial activities were evaluated on the basis of diffusive oxygen fluxes, extracellular enzymatic activities, and uptake of radiolabelled compounds (i.e. bicarbonate and leucine). Microbial communities and diversities were characterized via 16S rRNA Illumina tag sequencing.

Our data show that areas, where the simulated mining activity removed the reactive surface layer were most affected, even after 26 years. Most microbial and biogeochemical characteristics at these sites still resemble conditions of deeper sediment layers, with strongly reduced microbial abundances, activities of extracellular enzymes involved in organic matter degradation, respiration rates, and inorganic carbon fixation rates. A significant impact was also observed for the bacterial and archaeal community structure and diversity that differed considerably from communities found at reference sites. Similar effects were also identified at another microhabitat, where surface sediments were still present but largely reworked into ripple-like structures. Also here microbial and biogeochemical characteristics were more similar to subsurface layers than to undisturbed sites.

We conclude that deep-sea mining reduces microbial activities, and changes their community structure and consequently their function in manganese nodule ecosystems for decades. Differences between microhabitats indicate that strong sediment redistribution and especially the loss of the surface layer represent the strongest impacts. Since microbes represent the basis of a multi-trophic food web, higher trophic levels and larger organisms may also be indirectly affected by the observed changes.

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Megafauna community patterns related to terrain variations in the abyssal North Pacific

Simon-Lledo, Erik1-2-, Bett, Brian J.2, Durden, Jennifer M. 2, Huvenne, Veerle A. I. 2, Jones, Daniel O. B. 2

1University of Southampton, National Oceanography Centre, Southampton, UK. 2National Oceanography Centre, Southampton, UK

The ecological characterisation of abyssal plains has been historically limited by their size and remoteness. Nevertheless, the advance of modern underwater technology in the last decades has revealed that abyssal plains are more complex environments than it was traditionally thought. In these areas, oceanic crust spreading processes and fractures often shape the seafloor as a continuous succession of crenulated ridges, low profile valleys, and flat zones. Terrain variations have commonly shown to influence the structure of benthic populations in marine environments, by modulating habitat complexity, local current regimes, and/or nutrient fluxes. However, the influence of macro-habitat morphology on benthic communities living in abyssal plains is largely unexplored, especially below the abyssal hill level (bathymetric range < 400 m).

Here we show differences in benthic megafauna community composition detected amongst three morphologically different areas of the north-western Area of Particular Environmental interest number (APEI) in the CCZ: a flat, a ridge, and a valley zones. These where delineated in accordance to bathymetric derivatives variations (bathymetric position index and terrain ruggedness), mapped from a multibeam dataset obtained at ~100m resolution. A total of 9 seafloor photographic transects (3 per stratum) were assessed for megafauna, enabling the detection of more than 22,000 animals within an area of 15,000 m2 of seabed (7800 pictures). Community composition, species density, diversity (H’), and evenness (J’) indexes showed significant variations between the 3 strata, suggesting that macro-habitat heterogeneity may play an important role in the development of benthic communities below the abyssal hill scale in the CCZ. Our capacity to map biological variations in polymetallic nodule fields, where deep-sea mining exploitation could start in coming years, will ultimately determine the success regulation measures, key for a successful preservation of these habitats in a near future.

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Tools for Rapid Biodiversity Assessment in the deep-sea: an overview

Ann Vanreusel (UGent) and Felix Janssen (AWI) and the author team of MIDAS report D10.4

Rapid biodiversity assessment (RBA) refers to time efficient tools that allow to collect information on the present biodiversity in a given area. RBA is never an exhaustive inventory and will not record every species in an area; it would typically target specific groups, such as particular size classes (micro-, meio-, macro- or megafauna), specific taxa or functional groups (specific trophic levels, key species, habitat engineers,..) for which methods will differ according to organism size, habitat and distribution, among other biological characteristics. RBA in terrestrial environments is often based on key taxa (e.g., specific bird or mammal species) that are used as proxies for the health and integrity of ecosystems. In the deep sea however there is no information on key taxa available yet. Furthermore using a rapid method may imply a quality loss in comparison to traditional methods where more time is given to identify specimens to the lowest taxonomic level. Only when RBA methods are guaranteed to give the same or at least similar level of information as the validated taxonomic expert-based methods they can be applied in a monitoring or an Environmental Impact Assessment (EIA) program. If this is not the case, they should be applied with caution, especially in remote deep-sea systems where key taxa or functional groups, or particularly vulnerable taxa or indicator taxa are not yet identified.

During MIDAS several emerging RBA tools that are potentially applicable to address effects of deep-sea mining on biota living in these ecosystems were tested with a focus on the seafloor-associated biodiversity since here the impacts are expected to be severe due to the removal and disturbance of the substrate. We identified two main categories for rapid biodiversity assessment for sea-floor associated biota. The first category refers to non-invasive, imaging-based techniques such as high resolution video or photographic image surveys. The second category is based on material of collected specimens where the present biodiversity is assessed through molecular and/or morphological techniques. In general, image-based assessments are restricted to larger morphological features. Hence they typically only cover diversity of epifaunal macroscopic organisms (megafauna). On the other hand, imaging techniques also provide visual information over larger stretches of the habitat. Using this information, biodiversity patterns may be connected to characterizations of the natural habitat or mining-related disturbances. The sampling-based methods may allow to combine detailed morphology and molecular analysis of organisms, although some analysis are destructive and do not allow an integrative approach. Their spatial/temporal coverage will be lower within a given time frame, but the methods potentially cover a wide taxonomic/functional representation of groups, and may target both epi- and endofauna, typically with a focus on small organisms. In case of sediment samples, analyses of organisms may be accompanied by detailed physical and chemical analyses at a small spatial scale.

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Testing monitoring approaches during an industry-led Field Testing Cruise Ian Stewart, Fugro EMU

The MIDAS demonstration cruise successfully combined industry experience in ecological survey methods and academic advances in habitat surveying technology (WP10), ecological restoration techniques (WP6) and ecotoxicological monitoring (WP3). The cruise objectives were to trial novel environmental monitoring technologies and techniques developed by MIDAS partners and to assess their applicability to industry-standard environmental baseline surveying, and environmental impact assessment (EIA).

Participants from academic institutions Geomar, Coronis, Universidade dos Açores, Universidade do Algarve, Seaport Texel, and industry partners Fugro, James Fisher Subsea and Interocean took part in the MIDAS demonstration cruise in the EEZ of the Azores in July 2016. Operations ran 24 hours per day for the eight-day duration of the cruise, with no weather or technical downtime. An industry-standard light work-class remotely operated vehicle (ROV) was deployed from the RV Pelagia for habitat mapping, change detection studies, coral transplantation, and ecotoxicological experiments. An online positioning suite was integrated with the vessel’s Kongsberg HiPAP 500 ultra-short baseline (USBL) navigation system. The NIOZ drop-down HD camera hopper system was deployed for kilometre-scale video habitat mapping transects. Video survey data and positioning data were integrated and annotated using the vessel’s on-board OFOP system for ROV and hopper acquired data.

Condor seamount was chosen as a representative deep sea mining (DSM) survey location as it provided an appropriate range of habitats, rugosity and depths to trial the monitoring technologies. The Universidade dos Açores had sufficient local knowledge of the composition, patchiness and distribution of habitats to enable the WP10 participants to select suitable habitats to support quantitative comparisons of different technologies and methods. Studies were conducted in water depths ranging from 200 m to over 1100 m. The cruise team evaluated the advantages and disadvantages of various aspects of the deployment platforms for habitat mapping and change detection, and the inherent traits and limitations of subsea acoustic positioning and navigation systems.

The evaluation of currently available and developing subsea mapping and monitoring technology, deployment platforms and associated technologies on this cruise has demonstrated the importance of selecting tailored survey methodologies for specific DSM deposit types, biogeography and ecosystems. The spatial and temporal scale of sampling for DSM will need to be determined according to the individual ecosystem, and may require an iterative survey approach, depending on the a priori knowledge of the environment. The findings of these studies will support further productive research that is necessary to overcome the technical and operational challenges of environmental survey and data acquisition at appropriate scales in the deep sea. Further collaborative research between industry and academia will improve practical environmental survey and monitoring methods for deep sea mining. The Horizon 2020 funded ¡VAMOS! project, the ERDEM EIP on Raw Materials, and the EIT KIC Raw MatTERS programme all provide opportunities to continue to build upon the MIDAS findings and to develop new technologies and methods

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Semi-automated image analysis for meter to kilometer scale habitat mapping at Condor sea mount

Timm Schoening, Telmo Morato, Ian Stewart, Jens Greinert

GEOMAR Helmholtz-Centre for Ocean Research Kiel, Germany

University of the Azores, IMAR, Horta, Portugal

Fugro EMU Limited, Edinburgh, UK

As a result of the MIDAS demonstration cruise to the Condor sea mount, days of HD video footage have been acquired as well as Tera-bytes of high-resolution stereo images. Live streamed video footage has been annotated on board around the clock by marine biologists for initial habitat analysis. The expected quantitative comparison of different survey methods (ROV vs. OFOS, flying at different altitudes, oblique vs. vertical camera angle, transects vs. mesh track patterns, etc.) requires a fully annotated dataset which can only inefficiently be obtained by hand.

Semi-automated image processing methods will be applied to the datasets to allow for adding semantics to the visual data. Based on the existing manual annotations for small scale objects (substrate and individuals) and computed visual features, this will allow to create kilometer scale habitat maps.

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Monitoring Seafloor Changes from 3D Optical Maps

Klemen Istenic1, Nuno Gracias1, Josep Quintana2 and Rafael Garcia1,2

1 University of Girona, Spain

2 Coronis Computing SL, Spain

The importance of monitoring physical alterations, as well as the potential effects of particle-laden plumes and other toxic chemicals released during the mining process on the seabed and the deep-sea ecosystems, is undisputable. Detecting and potentially quantifying the physical changes is a painstaking and time-consuming task, which can prove to be overwhelming if performed manually for small scale changes over increasingly large areas.

Unfortunately, only few solutions exist to monitor the underwater environment, where sensing is far more difficult than in terrestrial problems, and accurate tools such as lasers have serious limitations in practice. Optical sensing provides a good trade-off for covering moderately large areas while obtaining a detailed environment representation. Optical mapping has been used by our team, focusing on partially automated change detection techniques in multiple sequences of high resolution underwater video imagery.

An exemplary study on the application of mapping techniques for change detection was performed based on imagery of a deep-sea test site acquired during the MIDAS 2016 cruise, over the Condor seamount in the Mid Atlantic Ridge. A set of 3D models of the inspected area were constructed using state-of-the-art techniques, such as Structure from Motion (SfM) and Multi-View Stereo (MVS). While a few attempts have been carried out in the past for applying these methods in underwater scenarios, the results are often of unpredictable quality, due to the unfavourable underwater medium and the large number parameters and settings that affect the the image acquisition process. For this reason, a series of recommendations will also be included on the data acquisition and subsequent processing, which have been identified throughout the research and field experiments. The goal is to facilitate the reproducibility of high quality mapping.

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Restoration tools for cold-water communities impacted by mining activities

Carreiro-Silva M, Martins I, Godinho A, Carvalho A, Rodrigues F, Rakka, M., Pham C, Bilan M, Colaço A, Morato T

IMAR-Instituto do Mar & MARE – Marine and Environmental Sciences Centre 9901-862 Horta, Portugal

Ecological restoration has been successfully used as a management tool to reverse environmental degradation caused by human activities across terrestrial and coastal ecosystems, but has so far never been applied to deep-sea ecosystems. During the MIDAS demonstration cruise to the Condor Seamount (Azores), we tested the feasibility of using active and passive restoration activities as tools for the restoration of cold water communities potentially impacted by mining. This pilot restoration action consisted in testing the use of coral transplantation techniques with the octocoral Dentomuricea meteor; a common species on coral gardens in the Azores. Corals were fragmented into coral nubbins and transplanted to the summit of Condor using fauna landers. Three areas differing in coral densities (low, medium, high) were selected for the deployment of the landers, with the objective of determining if the proximity of transplanted corals to natural coral populations would influence their survival and ability to attract associated fauna, thus restoring natural ecosystem functioning.

The same landers were also used to test the ecological benefits of passive restoration (also called assisted spontaneous regeneration) of cold-water communities impacted by SMS plumes, after cessation of the mining activity. For this pilot study the recovery potential of corals after being intoxicated with cooper, the main trace metal present in SMS plumes, was assessed using an experimental approach. The study also tested whether the recovery capacity of these corals would be similar in injured/damaged coral colonies by mining activities, and intact colonies. Four types of coral “treatments” were used: (1) Cu intoxicated corals; (2) Cu intoxicated corals with injuries; (3) Non- intoxicated, non-injured corals; (4) Non-intoxicated but injured corals. The hypothesis tested was that corals that are both intoxicated and injured can have a lower chance of recovery because they cannot cope as well with potential epiphytic fauna (zoanthids, hydrarians, bryozoans, etc) that may settle on injured coral branches.

The survival rates and condition of coral fragments for both set of studies were assessed using ROV video and photography, 1 week after coral deployment (during the MIDAS cruise). One lander from each set of three landers were collected after 2 months of coral exposure while others will be collected over a longer time period (1-2 years). This presentation will provide a detailed description of the design of the in situ studies, preliminary results and discuss the applicability of deep-sea restoration tools as potential mitigation actions to be used by the mining industry.

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Abstracts for poster presentations

Listed in alphabetical order

70

Merging AUV-based multibeam and image data to map the small-scale heterogeneity of Mn-nodule distribution

Evangelos Alevizos1, Timm Schoenning1, Kevin Köser1, Mirjam Snellen2, Jens Greinert1

1 GEOMAR Helmholtz-Centre for Ocean Research Kiel, Germany

2 Acoustics Group, Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, 2629 HS Delft, the Netherlands

AUVs offer the unique possibilities for exploring the deep sea seafloor in high resolution over large areas. We highlight the results from AUV-based multibeam echosounder (MBES) bathymetry / backscatter and digital imagery from the DISCOL area acquired during SO242 in 2015. AUV bathymetry reveals a morphologically complex seafloor with rough terrain in seamount areas and low-relief variations in the Mn-nodule covered, sedimentary abyssal plain. Backscatter provides valuable information about the seafloor type and particularly about the influence of Mn-nodules on the response of the transmitted acoustic signal. Primarily Mn-nodule abundances were determined by means of automated nodule detection on AUV seafloor imagery and nodule metrics such as nodules/image and nodules/m2 were calculated automatically for each image allowing further spatial analysis within GIS in conjunction with the acoustic data. AUV-based backscatter was clustered using both raw data and corrected mosaics. In total three unsupervised methods were utilized for backscatter clustering. Bayesian statistical analysis and PCA were applied to the raw backscatter values resulting in six and four acoustic clusters, respectively. In addition ISODATA clustering was applied to the backscatter mosaic and its statistics (mean, mode, 90th and 10th quartile) suggesting an optimum of six clusters. Part of the nodule metrics data was used together with bathymetry, derivatives (slope, rugosity. BPI, concavity and curvature) and backscatter statistics for predictive modelling of the Mn-nodule density using random forests. Results show that acoustic clusters, predictions from random forest modelling and image-based nodule metrics show very similar spatial distribution patterns with acoustic clusters clearly delineating nodule-free areas. A strong correlation of nodule occurrence with fine scale BPI and concavity of the bathymetry can be seen; backscatter classes reveal a gradient of decreasing nodule occurrence in N-S direction which is also evident in AUV imagery. These observations imply that nodule abundances are affected in general terms by local micro-bathymetry in a way that is not yet fully understood. However it can be concluded that nodule abundances can be sufficiently analysed by means of acoustic clustering and multivariate predictive mapping which allows predicting the spatial occurrence of Mn-covered areas as important habitat in the deep sea in a much more robust way than previously possible.

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Recovery of hydrothermal vent communities after a volcanic eruption Sabine Gollner1,2, Breea Govenar3, Pedro Martinez Arbizu2, Susan Mills4, Nadine Le Bris5, Markus

Weinbauer6,7, Timothy M. Shank4, Monika Bright8

1Royal Netherlands Institute for Sea Research (NIOZ), Ecosystem Studies, Korringaweg 7, 4401 NT Yerseke, The Netherlands; sabine.gollner@nioz.nl; 2German Center for Marine Biodiversity Research

(DZMB), Senckenberg am Meer, Am Südstrand 44, 26382 Wilhelmshaven, Germany; sabine.gollner@senckenberg.de

3Biology Department, Rhode Island College, 600 Mt. Pleasant Ave., Providence, RI 02908, United States of America

4Biology Department, 266 Woods Hole Road, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, United States of America

5CNRS-UPMC UMR8222, LECOB Observatoire oceanology, 66650 Banyuls sur Mer, France 6Sorbonne Universités, UPMC Univ Paris 06, UMR 7093, LOV, Observatoire océanographique, F-

06230, Villefranche/mer, France 7CNRS, UMR 7093, LOV, Observatoire océanographique, F-06230,

Villefranche/mer, France 8Department of Limnology & Bio-Oceanography, University of Vienna, Althanstrasse 14, 1090 Vienna,

Austria

Polymetallic sulphide mining may put large-scale pressures on faunas at deep-sea hydrothermal vents. Fauna living at vents also face natural disturbance events such as volcanic eruptions. Understanding community recovery mechanisms of the vent fauna will help to formulate plans for future conservation. In 2006, a major volcanic eruption killed almost all fauna at the 9°North East Pacific Rise region. We monitored recovery at vents and on vent-proximate basalt by deploying and recovering settlement substrates (plastic kitchen sponges) one, two and four years after the eruption. In addition, we collected samples from the overlying water column with a pelagic pump to determine the abundance of potential colonisers. Species recovery patterns differed between the two habitat types. At vents, initial recovery was relatively quick and about 40% of original meio- and macrofauna species had returned four years after the eruption, which may be due to the good dispersal capabilities of vent endemic macrofauna and vent endemic dirivultid copepods. On basalt, a habitat showing low diversity of macrofauna but highly diverse meiofaunal communities, recovery of meiofauna was slow with only 28% species returned to the site. The more limited dispersal capabilities of meiofauna basalt specialists such as nematodes or harpacticoid copepods probably caused this pattern. Our results suggest that not only vent communities, but also species-rich communities of vent-proximate habitats require attention in conservation efforts (1).

1. Gollner, S., Govenar, B., Martinez Arbizu, P., Mills, S., Le Bris, N., Weinbauer, M., Shank, T.M., Bright, M. Differences in recovery between deep-sea hydrothermal vent and vent-proximate communities after a volcanic eruption. Deep-Sea Research I. 2015;106:167-82.

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Xenophyophores and komokiaceans from the different claim areas of the Clarion-Clipperton nodule field

O.E.Kamenskaya1, A.J.Gooday2

1- P.P. Shirshov Institute of Oceanology RAS, 117997 Moscow, Nakhimovsky prosp. 36, Russia

2- National Oceanography Centre, University of Southampton Waterfront Campus, European Way, Southampton SO 14 3ZH, United Kingdom;

Ferro-manganese nodules are a potentially major source of commercially important metals in the deep sea. Future mining of this seafloor resource may have dramatic and unforeseen effects on the deep-sea ecosystem. The Clarion-Clipperton ferro-manganese nodule field, located at the abyssal depths in the eastern equatorial Pacific (CCZ), is one of the main areas for future deep-sea mining. We have examined xenophyophores and komokiaceans, large agglutinated protists attributed to foraminifera, from four claim areas licensed by the International Seabed Authority for seabed mining: the German, IOM in the eastern part of the CCZ, and the Russian and French areas in the central part. Material was collected using mega-, multi-, boxcorers, and epibenthic sledges. In some areas xenophyophores dominated the megabenthos in terms of density and diversity, while komokiaceans were one of the most abundant and diverse group of macrobenthos. The largest collection of xenophyophores was obtained from the Russian claim area. In total, 21 species were recognized, only 5 of which had been described scientifically. Maximal density on the seafloor were 12 specimen per m2. Among komokiaceans and related protists, we recognize 169 species from the CCZ, only 29 of them were described. Within the nodule field species of komokiaceans were distributed quite evenly, although their density and diversity depended to a great extent of the type of gear and number of stations rather than the area of collection. In 3 subcores (cross-sectional area 3 cm2) taken from a multicorer in the IOM area we found 86 species of komokiaceans. Another 4 quantitative samples, collected using a subcorer (cross-sectional area 20 cm2) from boxcores in the German claim area, yielded 41 species. A similar number of species (37 species) was present in two boxcorer samples from the French claim area in the central CCZ. The quantitative samples from the eastern and central parts of the CCZ yielded similar species numbers: 138 species from epibenthic sledge residues in the German area and 124 species from 8 boxcorers from the Russia claim area (about 90% were undescribed). Earlier studies by L.A. Levin, B. Lecroq and others have revealed that the abundance and species diversity of macro- and meiobenthos increased when xenophyophores were present, while the smaller komokiacean tests yield many DNA sequences originating from a diversity of other organisms. Thus these protists make important contributions to mega- and macrobenthic diversity and biomass in the polymetallic nodule field. Given their abundance and potentially important ecological role, an improved knowledge of the diversity and ecology of xenophyophores and komokiaceans is important for understanding the recovery of benthic communities after mining impacts on the ocean floor.

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New observatory technologies that monitor gas hydrate stability off Norway

A. Kopf, T. Fleischmann, C. Zöllner, G. Bohrmann, H. Sahling, J.H. Körber

MARUM, Univ. Bremen, Leobener Strasse 2, 28359 Bremen, Germany

The Norwegian Margin off Svalbard bears massive gas hydrates that have been demonstrated to be metastable as a function of seasonal temperature variations. At the uppermost part of the continental slope, above the gas hydrate stability zone, various methane emission sites were previously detected as acoustic plumes in echosounder recordings. New investigations interpret the gas emission by methane from hydrate decomposition due to an increase in water temperature of 1°C during the past 30 years, which causes a downward movement of the upper boundary of the gas hydrate stability zone by 38 m.

Albeit a natural trigger, the induced temperature changes may be similar in effect to those induced by gas hydrate exploitation using warm water, as is currently discussed by several parties with a severe interest in mining methane from subseafloor gas hydrates. In order to assess the amount of gas that may be released even from moderate increase in temperature, cruise MSM57 with German RV Merian drills double boreholes using the mobile drilling sytem MeBo to sample hydrates for the first time in this area. Chemical analyses of the samples and physical parameters will be measured to define the phase boundary very precisely. In addition, both seafloor- and borehole based monitoring technology was developed in MIDAS to collect crucial data concerning gas hydrate dissociation and sediment deformation processes as a function of temperature over two full seasonal cycles. The aim ist o assess the risk of slope failure as a function of gas hydrate dissociation.

The MeBo borehole observatories monitor pore pressure, temperature and tilt, which would be a good indicators for gas hydrate and sediment deformation processes as a pore pressure increase in the formation would mean methane release, increasing stress and pore volume reduction, or both. The observatory is hosted in the uppermost portion of the drill string, which remains in the hole after completion of coring. A buoyant unit containing an Iridium telemetry can be released from the observatory in ordert o transmit data or an alert independently, e.g. after a pre-programmed threshhold value (e.g. a certain degree of tilt or an anhanced pore pressure level) is exceeded. Such an early warning mechanism could be used in similar scenarios where gas hydrate is exploited at the seafloor during DSM activities. The device is versatile, cost-efficient, and will be available commercially in case of demand.

We also developed trawl-safe moorings for quantification of gas hydrate dissociation/methane bubble release on the seafloor. As main component, the moorings host an Imagenex 881 circumference sonar system that may be used for both bedform monitoring or gas bubble quantification. This system has been mounted at an upward-looking angle of appx 30° and is programmed to scan a window of 160° only. In addition, P-neutral seafloor batteries as well as a data acquisition and additional transducers to measure pressure, temperature and electric conductivity are placed within the frame. Both transients in P and T, and more importantly freshening of the seawater as well as increasing amounts of methane bubbles over time enable us to identify and quantify gas hydrate instability over time. Given that the majority of the components are available off-the-shelf, the system represents an affordable way to monitor gas hydrate destabilization processes, either induced by natural or man-made processes.

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A Large Scale Visual Mosaic of the Central DISCOL Area

Kevin Köser, Anne Jordt, Timm Schoening, Jens Greinert

DeepSea Monitoring Group, GEOMAR Helmholtz Centre for Ocean Research Kiel

Monitoring the impact of deep sea mining activities requires large scale observations of the seafloor prior, during and post extraction. To assess large areas (ultimately, on the order of square kilometers) in due time we propose to use overlapping AUV imagery and to create large, high-resolution, georeferenced mosaics. During Sonne cruise SO242 to the DISCOL experimental area in the Peru basin, large amounts of such image material have been captured using a novel ultra wide angle imaging system onboard GEOMAR's AUV Abyss. In this contribution we show a result of renavigation using visual data. We partially compensate for the changing lighting conditions that make corresponding points look very different throughout the image sequence. Afterwards, we automatically find correspondences in the images and make the AUV trajectory consistent with these visual observations using techniques called "simultaneous localization and mapping" (SLAM), or, structure from motion (SfM) in the machine vision literature. After the images and the trajectory are visually consistent, we stitch together in the order of 10000 images to produce a gigapixel mosaic that resembles a high resolution aerial photograph of the seafloor with the water virtually removed. This geo-referenced image provides a common coordinate system for visual observations and can be subdivided into tiles. This material can be analyzed by different experts from biology or geology for identification, characterization and quantification. The long-term goal is to repeatedly extract such mosaics in order to monitor spatial patterns prior, during and post mining activities.

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DeepSurveyCam – A deep ocean optical survey system Tom Kwasnitschka*, Kevin Köser, Jan Sticklus, Marcel Rothenbeck, Tim Weiß, Emanuel Wenzlaff,

Timm Schoening, Lars Triebe, Anja Steinführer, Colin Devey and Jens Greinert

GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstr. 1-3; Germany

Underwater photogrammetry and in particular systematic visual mapping of the deep sea is by far less developed than techniques on land or in space. The main challenges are the rough conditions with extremely high pressure, the accessibility of target areas (container and ship deployment of robust sensors, then diving for hours to the ocean floor), the limitations of localization technologies (no GPS) and the absence of natural light, which complicates energy budget considerations for deep diving flash-equipped drones. Refraction and focus effects influence image formation while attenuation and scattering degrade the image quality and limit visibility. We present an AUV-based optical survey system intended for autonomous visual mapping of large areas of the seafloor (square kilometers) in up to 6000 m water depth. We compare to existing systems and discuss tradeoffs such as resolution vs. mapped area and show results from a recent survey with 90,000 mapped square meters of deep ocean floor.

The GEOMAR AUV ABYSS prior to launch, equipped with b) a high resolution camera behind a dome port and c) a novel LED flash system

The content is published under same title in: Sensors 2016, 16, 164; doi:10.3390/s16020164

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Black corals (Antipatharia) of the Clarion-Clipperton Fracture Zone

Tina Molodtsova1, Dennis Opresko2

1P.P. Shirshov Institute of Oceanology RAS, Moscow, Russia

2U.S. National Museum of Natural History, Smithsonian Institution, Washington, DC, USA

The ecosystems of the seafloor associated with massive deposits of sulphides and polymetallic nodules in the last few years have been in the growing focus of attention because of accelerating interest in deep seabed mining. The Clarion-Clipperton Fracture Zone (CCFZ) in the north-east Pacific is regarded as the main area for potential Fe-Mn nodules mining. This area is approximately 7200 km in width occupying 6×106 km2. Because of the great depth and remoteness the sampling effort for the area is limited and our knowledge of the megafauna that inhabits this region is based primarily on seabed photographs and few collected specimens. Five species of black corals from three genera were found in several taxonomic and reference collections from the CCFZ from depths 4158─5100 m. At least two more species are known from underwater photographs only. In the CCFZ black corals have been found almost exclusively at nodule-bearing sites and as it was shown previously they can comprise up to 17% of the nodule epifauna. This can be correlated with the requirement of most black coral species for a hard substrate for the attachment. Because antipatharians are suspension-feeders they are at potential risk for adverse impacts as a result of deep-sea mining.

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Evaluation of extraction techniques for REYs from marine sediments and polymetallic nodules

Kate Peel1, Amaya Menendez2, Rachael H. James2 and Douglas Connelly1

1 Marine Geoscience, National Oceanography Centre, University of Southampton Waterfront Campus, European Way, Southampton SO14 3ZH, UK

2 Ocean and Earth Science, National Oceanography Centre, University of Southampton Waterfront Campus, European Way, Southampton SO14 3ZH, UK

Deep-sea clays and polymetallic nodules contain relatively high concentrations of rare earth elements and yttrium (REYs), and there is growing interest in exploiting them as a resource. To assess the potential impacts of deep-sea mining on the marine environment the processing techniques of such resources should be taken into consideration. Terrestrial sources of REYs are found within a variety of minerals in geologically diverse deposit types, and a long process with multiple stages using aggressive reagents is required to concentrate, extract and refine the REYs. In contrast, it has been proposed that REYs are easily extractable from marine clays using weak acids, low temperature and short time frames (Kato et al, 2011). Nodules are composed primarily of manganese oxides, iron oxyhydroxides and minor amounts of aluminosilicate minerals, so REYs and other resource metals (nickel, copper, cobalt and manganese) could be similarly straightforward to extrac! t with acid leaching.

We conducted a set of laboratory-based batch experiments to evaluate the effectiveness of acid leaching for the extraction of REYs and metals of commercial interest (Ni, Cu, Co, Mn) from marine sediments and nodules. Three sediment samples from the North Atlantic, including a brown clay, a red clay and a micronodule-rich clay; and 5 nodule samples, including two USGS certified reference materials and 3 samples from the NERC- led cruise JC120 in April-May 2015 were leached with: i) 0.5 M HCl, ii) 0.2 M H2SO4 and iii) 0.2 M oxalic acid/ammonia oxalate buffer, for up to 12 hours at room temperature. We also investigated the release of harmful waste products (including uranium and thorium) by reintroducing washed or unwashed leached residues to seawater in further laboratory-based batch experiments.

Our results indicate that leaching sediments and nodules with dilute acids is moderately effective, releasing up to 51% of the total REYs from sediments and up to 63% from the nodules. Maximum recoveries of major elements were 55 – 98% for sediments and 12 - 46 % for nodules. Unwanted U and Th were also released into the leachate solution. The re-release experiments with seawater showed very little REYs, major elements or U and Th were mobilised from the leached residues. Although further refinement of these techniques would be required to increase recoveries to a commercially viable level, these findings demonstrate that leaching with dilute acids at low temperature and short time scales could be sufficient for processing marine sediments and nodules.

Reference: Kato Y. et al. (2011) Nature Geosci. 4, 535-539.

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Correlation between small-scale deep-sea habitats and Mn-nodule abundances in the German PA I area in the CCZ

Anne Peukert, Jens Greinert, Timm Schöning, Kevin Köser, Evangelos Alevisos

GEOMAR Helmholtz-Centre for Ocean Research Kiel, Germany

More than 50 000 deep-sea photographs from the CCZ, obtained by Geomar’s AUV “Abyss”, enable semi-quantitative assessments of nodule coverage on local scale. AUV-obtained high-resolution acoustic data provide insights into benthic deep sea small-scale habitats, which were studied for relationships between local morphology and nodule abundance, derived from semi-automated image analysis. Although no simple, global valid relationship could be derived, the data reveal a very sensitive dependency of nodule coverage to fine-scale morphology of less than 1 m vertical height difference. Increased nodule coverage could be correlated with slopes > 1° and concave terrain structures. Other factors, such as differences in crustal structure, the specific geological, oceanographic setting and the geochemical environment, seem to be essential factors influencing nodule abundance within the 12 km2 large study area. The results contribute to a better understanding and modelling of the nodule coverage at the seafloor, they highlight the small scaled heterogeneity of Mn-nodule distribution and as such the benthic habitat. This has direct implications on Mn-nodule resource assessments, the way mining will occur (along straight lines or following the highest Mn-nodule occurrence) and the resilience of the resilience of the ecosystem against mining-induced impacts.

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Food web complexity across hydrothermal-vent fields of the North Mid-Atlantic Ridge

Marie Portail1, Cécile Cathalot2, Ana Colaço3, Yves Gélinas4, Pierre-Marie Sarradin1, Jozée Sarrazin1

1 Institut Carnot Ifremer EDROME, Centre de Bretagne, REM/EEP, Laboratoire Environnement Profond, F-29280 Plouzané, France.

2 Institut Carnot Ifremer EDROME, Centre de Bretagne, REM/GM, Laboratoire Cycles Géochimiques et Ressources, F-29280 Plouzané, France.

3 IMAR – Department of Oceanography and Fisheries University of the Azores, Cais de Sta. Cruz, Horta (Azores), Portugal

4 GEOTOP and Chemistry and Biochemistry Department, Concordia University, Montréal, Québec, Canada.

Addressing and comparing ecosystem functioning across hydrothermal-vent fields enhance our comprehension of how natural environmental conditions affect faunal communities and ecological processes, a prerequisite in the perspective of deep-sea mining. Menez Gwen, Lucky Strike and Rainbow hydrothermal-vent fields from the North Mid-Atlantic ridge are related to distinct depths and geological contexts that result in variable fluid emission proprieties. Our study focused on epifaunal assemblages defined by Bathymodiolus azoricus foundation species that are common across the three vent fields and newly described gastropod assemblages from the Menez Gwen field. Food webs of eleven faunal assemblages were studied based on carbon and nitrogen stable isotope analyses. While potential dominant basal sources are similar, intra and inter-field variations of their relative contributions were found. Contributions of methanotrophy versus thiotrophy appeared to vary in accordance with associated reduced compound concentrations (methane and hydrogen sulphide). Common species across fields showed high trophic flexibility suggesting weak trophic links to the metabolic diversity of chemosynthetic primary producers that may be a key to their adaptation to environmental variability across ecosystems. At the community level, functional metrics, based on presence/absence and biomass matrices, were used to assess and compare food web complexity between fields Menez Gwen and Lucky Strike mytilid assemblages. Food web structures were, in each case, highly similar in terms of basal niche diversification, trophic specialisation and redundancy. Therefore, while environmental conditions and species compositions differed across these sites, their functioning appeared highly similar. This functioning similarity suggests that species ecological niche are not related to the nature of fluids and that different species may occupy equivalent niches across fields. Finally, same approach should be further tested on in situ experiments, mimicking environmental disturbances expected from mining.

Key words: Hydrothermal vent, food web, carbon and nitrogen stable isotopes, environmental conditions, Mid-Atlantic ridge

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The importance of manganese nodules for the life cycle of deep sea incirrate octopi

1Autun Purser, 1Yann Marcon, 1Felix Janssen, 2Henk-Yan Hoving, 2Uwe Piatowski, 3Michael Vecchione, 4Deborah Eason, 1Antje Boetius

1Alfred Wegener Institute, Am Handelshafen 12, D-27570 Bremerhaven, Germany 2GEOMAR, Düsternbrooker Weg 20, D-24105 Kiel, Germany

3Smithsonian Institution, PO Box 37012, MRC 153, Washington, DC 20013-7012, USA 4University of Hawai'i, Department of Geology and Geophysics, 1680 East-West Road, Honolulu,

Hawaii 96822, USA

Leg SO242/2 of an RV SONNE expedition to the DISturbance and reCOLonization (DISCOL) area in the manganese nodule ecosystem area of the Peruvian Basin in the framework of JPI Oceans program ‘Ecological aspects of deep-sea mining’ and MIDAS investigated the faunal and biogeochemical response and recovery to both recent (~5 weeks prior) and historical (~26 yrs prior) nodule removal and seafloor disturbances. Recently published by MIDAS partners, epifauna studies conducted within the Clarion Clipperton Fracture Zone (CCZ) as part of the same projects have shown the potential importance of manganese nodules as suitable hard substrate ‘islands’ onto which stalked fauna, such as deep sea sponges and crinoids, can settle and develop (Vanreusel et al., 2016).

At the DISCOL site, 27 deep sea incirrate octopi were observed actively feeding around the edges of Manganese nodules at depths of approx. 4100 m, using crevices between nodules as sites of refuge, and in two instances brooding eggs directly onto the stalks of dead deep sea fauna. Interestingly, no incirrate octopi were observed during any of the recent MIDAS / JPI Oceans cruises to the CCZ, Observed individuals represent at least two species, with several being identified as Vulcanoctopus sp. The majority appear to belong to the recently observed ‘Casper’ species, recorded by Remote Operated Vehicles from several locations within the Hawaiian archipelago, and as yet, undescribed.

Together with the recent Hawaiian observations, these new data increase the depth range of incirrate octopi by several hundreds of meters. Additionally they represent the first observations of incirrate octopi using other fauna as a brooding substrate.

Though the knock-on impacts on stalk supported small megafauna communities has been a known consideration for several decades (though better understood following MIDAS and JPI Oceans investigations) the potential impacts on larger semi-pelagic mobile fauna such as octopi has not been considered to date. In this study we show that potentially the loss of nodules will have direct impacts on these larger megafauna. Tantalisingly, the observations of the incirrate octopi in the Hawaiian archipelago were made in areas also abundant in stalked fauna. Survey dives within these manganese crust rich regions of seafloor covered considerably less area than the DISCOL work carried out during SO242/2, and therefore there is the potentiality that stalks in these commercially interesting ecosystems represent habitat resources at risk from mining activities.

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A rich dataset acquired at Condor Sea mount

Timm Schoening, Jens Greinert

GEOMAR Helmholtz-Centre for Ocean Research Kiel, Germany

A variety of digital data has been acquired during the MIDAS demonstration cruise to the Condor sea mount. This includes benthic camera surveys with HD and SD video, calibrated 12MPix Stereo images, high-resolution multibeam data, DVL and USBL navigation data, attitude and heading data as well as selected CTD surveys. This rich dataset allows to approach a multitude of MIDAS challenges: comparisons of habitat surveying methods, comparison of imaging platforms, resolution limits to species identification, navigation problems and solutions by fusion of different sensor readings are just the beginning.

This rich dataset will be made available online for free use to install a real-world benchmark dataset for 3D reconstruction, automated object detection and classification as well as navigation data processing and fusion.

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Slow microbial growth and recovery of microbial community structure after disturbances in the DISCOL experimental area

Tobias Vonnahme, Felix Janssen, Massimiliano Molari, Frank Wenzhöfer, Antje Boetius

HGF-MPG Group for Deep Sea Ecology and Technology at Alfred Wegener Institute, Bremerhaven, Germany and Max Planck Institute for marine Microbiology, Bremen, Germany

Investigations carried out during leg SO242/2 of RV SONNE to the DISCOL experimental area in Sep. 2015 show that the removal of the reactive surface layer by disturbances created in 1989 is still reflected in altered microbial standing stocks and activities. Based on measurements of microbial carbon assimilation rates (inorganic carbon uptake, oxygen uptake, leucine uptake) and the carbon and nitrogen content of the sediment, we estimated the time needed post-disturbance for microbial regrowth and community turnover to reach initial population sizes. According to these calculations, microbial cell numbers are expected to recover in less than a year. Surprisingly, 26 years after the disturbance, population sizes still do not reach the level found at reference sites. Also the community structure still differs at the disturbed sites. Various explanations for the lack of growth are possible: Grazing, viral lysis, removal of manganese nodules, and a lack of labile organic matter are some of the potential mechanisms which may limit microbial population growth, in spite of the relatively high carbon assimilation rates.

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MIDAS 2015: List of participants

Last name First name Institution Email Aleynik Dimitry SAMS Dmitry.Aleynik@sams.ac.uk Ardron Jeff NOC jeff.ardron@gmail.com Ballas Gregory Ifremer gregory.ballas@ifremer.fr Bebbiano Maria UALG mbebian@ualg.pt Bettencourt Raul IMAR raul.s.bettencourt@uac.pt Bezerra Tania Nara UGent tania.campinasbezerra@ugent.be Billett David DSES david.billett@deepseasolutions.co.uk Bonifacio Paulo Ifremer paulobonifacio@gmail.com Boomsma Wiebe IHC WBA.Boomsma@ihcmerwede.com Brincat John EC DG MARE Brown Alastair U.Southampton Alastair.Brown@noc.soton.ac.uk Caetano Ana Teresa EC DG Research Canals Miquel U. Barcelona miquelcanals@ub.edu Carreira e Silva Marina IMAR mcsilva@uac.pt Choi Jung Chan NGI JungChan.Choi@ngi.no Christiansen Sabine IASS sabine.christiansen@iass-potsdam.de Carreiro e Silva Marina IMAR mcsilva@uac.pt Cobley Amber NHM acc2g10@soton.ac.uk Colaço Ana IMAR / UAzores maria.aa.colaco@uac.pt Collins Jane U.Southampton jane_eva_collins@hotmail.co.uk Cuvelier Daphne IMAR daphne@uac.pt Dale Andrew SAMS Andrew.Dale@sams.ac.uk

Damian Hans-Peter German Env Agency hans-peter.damian@uba.de

De Wachter Tom DEME De.Wachter.Tom@deme-group.com Dell’Anno Antonio CONISMA a.dellanno@univpm.it Deusner Christian GEOMAR cdeusner@geomar.de Dom Ann Seas at Risk adom@seas-at-risk.org Duperron Sebastien UPMC sebastien.duperron@upmc.fr Durden Jennifer NOC jennifer.durden@noc.ac.uk Gambi Cristina CoNISMa c.gambi@univpm.it Garcia Rafael Coronis rafael.garcia@udg.edu Garziglia Sebastien Ifremer Sebastien.Garziglia@ifremer.fr Gebicka Aleksandra Wycliffe aleksandra.gebicka@gmail.com Gebruk Andrey Shirshov Institute agebruk@gmail.com Gianni Matt Gianni Consult. matthewgianni@gmail.com Gjerde Kristina Wycliffe kristina.gjerde@eip.com.pl Glover Adrian NHM a.glover@nhm.ac.uk Goulding Laura ERM Laura.Goulding@erm.com

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Last name First name Institution Email Guilini Katja UGent katja.guilini@ugent.be Gunn Vikki Seascape vikki.gunn@seascapeconsultants.co.uk Haeckel Matthias GEOMAR mhaeckel@geomar.de Hagemann Randi Statoil Hamann Kristin GEOMAR khamann@geomar.de Hauquier Freija UGent Freija.Hauquier@ugent.be Hauton Chris U. Southampton ch10@noc.soton.ac.uk Husson Berengere Ifremer berengere.husson@ifremer.fr Istenic Klemen U. Girona klemen.istenic@gmail.com James Rachael U. Southampton rachael.james@noc.soton.ac.uk Janssen Felix AWI felix.janssen@awi.de Johnson David Seascape david.johnson@seascapeconsultants.co.uk Jones Dan NOC dj1@noc.ac.uk Kaiser Stefanie SGN Stefanie.kaiser@senckenberg.de

Kakee Tomoko Yokohoma National Univ. kakee@ynu.ac.jp

Kemmotsu Uiko JAMSTEC uikok@jamstec.go.jp Knight Robert U. Southampton r.d.knight@soton.ac.uk Kopf Achim U.Bremen akopf@marum.de Lallier Laura eCOAST/UGent laura.lallier@ugent.be Lins Lidia UGent lidia.linspereira@ugent.be Macheriatou Lara UGent lara.macheriotou@ugent.be Machon Julia UPMC Julia.Machon@live.fr Mackintosh Siwart Dredging Today sm@navingo.com Maes Frank UGent Frank.Maes@ugent.be Marcon Yann AWI yann.marcon@awi.de Martins Ines IMAR / UAzores imartins@uac.pt Martinez Arbizu Pedro DZMB / SGN pmartinez@senckenberg.de McMeel Oonagh Seascape oonagh.mcmeel@seascape.co.uk McQuaid Kirsty U. Plymouth kirsty.mcquaid@plymouth.ac.uk Menendez Amaya NOC A.Menendez@soton.ac.uk Mestre Nélia U. Algarve neliamestre@gmail.com Mevenkamp Lisa Ugent lisa.mevenkamp@ugent.be Mouat John OSPAR john.mouat@ospar.org Morato Telmo IMAR / UAzores telmo@uac.pt Murphy Kevin ERM Kevin.Nurphy@erm.com Norman Rodney IHC r.norman@ihcmerwede.com Nugent Conn Pew Foundation cnugent@pewtrusts.org

Nunes Cintia Erasmus Univ. Rotterdam cintianunes@gmail.com

Okland Ingeborg U. Bergen Ingeborg.Okland@geo.uib.no Ortega Aleyda MTI a.ortega@mitholland.com Pape Ellen UGent Ellen.Pape@ugent.be

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Last name First name Institution Email Paterson Gordon NHM g.paterson@nhm.ac.uk Peel Kate NOC kate.peel@noc.ac.uk Peukert Anne GEOMAR apeukert@geomar.de Pham Christopher IMAR phamchristopher@uac.pt Piquet Berenice UPMC berenicepiquet@gmail.com Pirlet Hans VLIZ hans.pirlet@vliz.be Ravaux Juliet UPMC juliette.ravaux@upmc.fr Ribeiro Pedro IMAR / UAzores pribeiro@uac.pt Schoening Timm GEOMAR tschoening@geomar.de Singh Pradeep Arjan U.Bremen pradeep@uni-bremen.de Spencer Marla NHM/USOU M.Spencer@soton.ac.uk Spickermann Ralph UKSRL ralph.spickermann@ukseabedresources.co.uk

Stewart Ian Fugro EMU ian.stewart@fugro.com Schoening Timm GEOMAR tschoening@geomar.de Simon Lledo Erik USOU/NOC esl1n13@soton.ac.uk Stratmann Tanja NIOZ Tanja.Stratmann@nioz.nl Sweetman Andrew IRIS andrew.sweetman@iris.no Taboada Sergi NHM s.taboada-moreno@nhm.ac.uk Tinch Rob MEDIAN robtinch@gmail.com Turner Phil Duke University Philip.Turner@duke.edu Van de Kettereij Robert IHC r.vandeketterij@mtiholland.com Van den Hove Sybille MEDIAN sybille@median-web.eu Van Oevelen Dick NIOZ Dick.van.Oevelen@nioz.nl van Nijen Kris DEME van.nijen.kris@deme-group.com van Oevelen Dick NIOZ Dick.van.Oevelen@nioz.nl Vanreusel Ann U. Gent Ann.Vanreusel@UGent.be Verlaan Philomene U. Hawaii pverlaan@gmail.com Vink Annemiek BGR Annemiek.Vink@bgr.de Walmsley Simon WWF swalmsley@wwf.org.uk Weaver Philip Seascape phil.weaver@seascapeconsultants.co.uk Zander Timo GEOMAR tzander@geomar.de