MARNAUT

Spatial distribution and charaterization of seep faunal assemblages in Marmara Sea

12 May - 11 June 2007 Atalante / Nautile

Chief scientists: P. Henry, C. Sengor

Localisation

Indicators of cold seep areas

during the Marmarascarps cruise (2002)

28°0’0’’E 29°0’0’’E

41°0’0’’N

40°45’0’’N

40°30’0’’N

Scientific objectives

• To establish community structure with faunal quantitative samples Assessment of diversity, density, biomass

• To characterize trophic relationships between dominant megafaunal species using stable isotope analysis

• To compare the structure of cold seeps at different spatial scales (local and regional)

• To assess links between faunal distribution and in situ environmental factors (in collaboration with CNRS, …)

Observed organisms BIONIL (2006)

Habitat Fauna Sampling device

Tubeworms, pteropods Blade corer

Carbonate crusts Actinians, serpulids, gastropodes, bivalves, tubeworms

ROV claw

Sediments with biogenic mounds

Stomatopods (Crustacea, Eucarids)

Gravity corer

Fissures Siboglinids, sea urchins, galathae

ROV claw, sampling net

Soft sediments

© Marum/University of Bremen

Pre-selected microhabitats frompictures of Marmarascarps

Black patches of reduced sediments

Polychaetes, bivalves…

Bacterial mats and chimneys

Polychaetes, bivalves…

Carbonate crusts

Siboglinids, bivalves, echinoderms…

Sampling strategy

1. Site and habitat pre-selection

2. Habitat imagery

3. Faunal quantitative sampling : 3 replicates per habitatwith Nautile lasers visible on video capture/photo Soft sediments with: (2 hours)

suction sampler (epifauna) blade cores (endofauna)

Carbonate crusts with: (3-4 hours) suction sampler(epifauna)

Nautile claw (crusts) blade corer (endofauna underneath crust)

Carbonate chimneys: (3-4 hours) suction sampler(epifauna)

Nautile claw (crusts) suction sampler (attached small fauna)

On board tasks

• Recover faunal samples in wet lab

• Slice sediment cores in sections of different thickness

• Sieve faunal samples through a column of sieves

• Observe and determine taxa with binocular magnifier

• Fix samples with alcohol, formalin or freezing (-80°C)