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Meteor-Blog 3. August 2008: Successful Quest dive No. 217

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Bremen under water dive robot QUEST completed his 217th dive with success. Take a look at the deep sea world at REGAB pockmark and let yourself explain from PhD student Christina Bienhold why woodfall experiments are related to cold seep ecosystems.

Planetearth Blog

Does the biodiversity of deep-sea organisms play a role for the climate on Planet Earth? Questions all about marine research will be answered directly aboard of the German research vessel Meteor by cruise leader Prof. Antje Boetius and her crew. In cooperation with the geoportal from 17.08.08 to 24.08.08 they contribute a Science-Blog of METEOR expedition M76/3 GUINECO – MARUM research of fluid and gas seeps on the Westafrican continental margin. Technical highlight of the cruise is the remote-controlled under water robot QUEST4000 by MARUM that will be deployed for taking fauna and sediments samples and conduction of in situ experiments. Go on a dive down to places no other human being has ever seen before: explore the fascinating deep-sea fauna and watch the scientists’ work at gas and fluid seeps deep down on the ocean bottom.

Expedition M76/3b is a collaboration of MARUM – Center for Marine Environmental Sciences at Bremen University and its associated institutes MPI and AWI as well as the French research institute IFREMER and the University of Paris.

More Informationen of the Meteor-Blog, an overview of all contributions to the blog and expedition M76/3B:

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3. August 2008 (Author: Christina Bienhold)

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Today's Meteor-Blog is contributed by:

Christina BienholdHello, today it is again the GLOMAR PhD student Christina Bienhold (see blog from 17.07.08) reporting on the daily affairs on board of RV Meteor.

Successful Quest dive No. 217

After an aborted dive and two failed multicorer deployments yesterday, we started the Quest dive number 217 this morning at 8:30 am ship’s time. This dive was dedicated to the exploration of new habitats in the REGAB area. At a large mytilid mussel field (same bivalve family that our blue mussel belongs to) several measurements were conducted with different sensors, that can measure e.g. temperature, sulfide, pH and oxygen directly on site (picture 1).

3. August: Bild 1

Picture 1: Measurements of oxygen, temperature and pH with the „handheld“directly inside a mussel field. 

The mussels were sitting on carbonates, that were mixed with gas hydrates and in several spots we could observe gas (methane) emerging from underneath the mussels, ascending through the water column in little bubbles. Also, lots of shrimps and crabs were busily climbing the mussel beds. This fit perfectly the dinner menu, namely "Büsumer Krabbenbrot mit Spiegelei” (shrimps on bread with egg sunny side up) ;-).

3. August: Bild 2Picture 2: Petra Ristova and Christina Bienhold with their wood colonization experiment.

Another task of today’s dive was the sampling of a wood colonization experiment, that we had deployed in this area three days ago (picture 2). It consists of one large, around 2 m long piece of wood, to which 10 smaller logs (length around 20 cm, diameter 15 cm) are tied (picture 3). This experiment is going to stay on the deep sea floor for around 2 years until it is going to be sampled again, in order to investigate the colonization of macro- and microorganisms on the wood. Today’s sampling marks the beginning of this long-term experiment. Similar to whale carcasses and dead macroalgae, wood constitutes an organic input into the otherwise nutrient-poor deep sea. Degradation processes caused by deep-sea animals and microorganisms specialized in the degradation of wood lead to the development of chemical conditions comparable to chemosynthetic environments at cold seeps and hydrothermal vents. That is why we can find the same or closely related organisms in these different environments and comparative studies can yield interesting results on how these communities have evolved in the deep sea.

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Picture 3: Wood colonization experiment after it has been on the seafloor for three days. It will be visited again at the end of this cruise and in 2 years.

Towards the end of the dive 217 another bivalve field with vesicomyids was visited. Again several sensor-measurements were conducted, mussels collected for the biologists on board (picture 4) and push cores (sediment cores) retrieved (picture 5). This will enable a thorough characterization of these habitats and their inhabitants. When the ROV surfaces again in the late evening, these max. 30 cm long sediment cores will already be awaited by the biogeochemists and microbiologists on deck. They will be brought to the cold room immediately and subsampling for measurements of different parameters will be carried out during the night. Not before the early everyone will fall into their bunks, tired but satisfied with today’s successful dive.

Everyone on board is well.
Greetings to Germany and the rest of the world.

Christina Bienhold

3. August: Bild 4

Picture 4: Mussels are collected from a mussel bed with a net. On board the mussels will be investigated by our French biologists.

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Picture 5: Push cores are taken inside a mussel field.