Session 139 – Advances in ocean technology; autonomous instrument development and applications

Poster

The Gotland Deep Environmental Sampling Station - GODESS

Ralf D. Prien, Mareike Peterson, David Meyer, Detlef E. Schulz-Bull

What? Results

Dellwig, O., B. Schnetger, H.-J. Brumsack, H.-P. Grossart, and L. Umlauf (2012). Dissolved reactive manganese at pelagic redoxclines (Part II): Hydrodynamic conditions for accumulation. J. Mar. Sys., 90, 31-41, doi:10.1016/j.jmarsys.2011.08.007

Holtermann, P., L. Umlauf, T. Tanhua, O. Schmale, G. Rehder, and J. Waniek (2012). The Baltic Sea Tracer Release Experiment. 1. Mixing rates. J. Geophys. Res., 117, C01021, doi:10.1029/2011JC007439

Holtermann, P., and L. Umlauf. The Baltic Sea Tracer Release Experiment. 2. Mixing processes (2012). J. Geophys. Res., 117, C01022, doi:10.1029/2011JC007445

Meyer, D., R. D. Prien, O. Dellwig, D. P. Connelly and D. E. Schulz-Bull (2012). In situ determination of iron(II) in the anoxic zone of the central Baltic Sea using ferene as spectrophotometric reagent. Mar. chem. 130-131: 21-27. doi:10.1016/j.marchem.2011.12.002

Prien, R.D., Schulz-Bull, D.E. (2011), The Gotland Deep Envrionmental Sampling Station - GODESS, Oceans '11 IEEE/OES Santander, 6.-9.6.2011, Santander, Spain. doi: 10.1109/Oceans-Spain.2011.6003606

contributors: Uwe Hehl, Siggi Krüger, Lars Umlauf, Peter Holtermann

cooperations: Sea & Sun Technology GmbH, SubCtech GmbH

1531

Ship based measurements do not resolve intermittency and are biased towards mild weather conditions. Episodic changes, e.g. intrusions of water with higher dissolved oxygen concentration into the redoxcline, are missed.

Why?

The GODESS mooring is located close to the monitoring station 271 in the Gotland Deep at 57° 19.2‘ N, 20° 8.0‘ E. The Gotland Deep is characterised by a steep halocline leading to a redoxcline below. The water in the deep is anoxic under stagnant conditions (i.e. without major inflows). Intrusions of water with higher dissolved oxygen concentration can be observed in the redoxcline.

What next?

New payloads will allow to carry out more versatile targeted deployments. These will complement the measurement capability within the new research focus 1 Small- and Mesoscale Processes e.g. for the project group redoxcline.

underwater winch

moving profiling instrumentation platform (PIP)

recovery unit

bottom weight

The mooring consists of the bottom weight with ground line for emergency recovery, the recovery unit, the underwater winch and the profiling instrumentation platform.

The profiling instrumentation platform (PIP) carries the instrumentation, power supply and data logger. The PIP payload consists of a multi-parameter CTD (conductivity, temperature, pressure, turbidity, Chl a fluorescence, pH, ORP) and dissolved oxygen optode.

Measurements are taken during ascent of the PIP at a speed of 0.35 m/s.

more redox-relevant parameters

microstructure payload

Underwater winch and PIP drawn down at deployment.

PIP ready for deployment.

GODESS components on deck before deployment.

IOW METIS analyser for Fe(II) and Mn(II)

The new PIP2 has space for addi-tional sensors such as the optical nitrate- and HS—-sensor, the IOW wet chemical analyser and micro-structure sensors. This makes the profiling mooring GODESS an ideal testbed for new sensors.

TriOS ProPS optical nitrate-sensor

Aquadopp current profiler

Rockland Scientific MicroRider

photo: Rockland Scientific

photo: Nortek

photo: TriOS

Data from a 55-day winter deployment 16. November 2010 to 11. January 2011. Profiles were taken every 8 hours, 171 profiles in total. Dark and light gray lines show the isopycnals at 8 and 9.6 kg/m³ respectively.

Where?

Profiles from two successive monitoring cruises in 2010/2011 at monitoring station 271. Nothing is known about the transition between profiles.

Leibniz-Institute for Baltic Sea Research, Warnemünde Seestrasse 15, 18119 Rostock, Germany

These pictures result from the assumption of linear transition between the profiles shown above.