Polarstern / CAML expedition: review of the CAML campaign
Sea-cucumber / Scotoplanes globos
© G. Chapelle / IPF / Alfred Wegener Institut
The sea floor under ice shelves is extremely difficult to access. The fauna that exists there can only do so by feeding on what currents carry under the ice. When an ice shelf vanishes, the phenomenon also allows the return of light, phytoplankton, zooplankton and finally of the sea floor animals feeding on the "plankton rain". However, the return of this rich and diversified fauna so typical of Antarctic bottoms is often also disturbed by the scouring of icebergs born from the ice shelf collapse.
For these reasons, the recent disintegration of the Larsen A & B ice shelves offered a double opportunity.
- The first: To enable access to this poorly known environment and fauna.
- The second: To be able to follow the different steps of the recolonization process.
All these elements build the context of the Polarstern research program supported by CAML (Census of Antarctic Marine Life). In their attempt to understand the evolution of this particular fauna, scientists established what they call "stations". For each of the stations, as many different sampling tools as possible are operated, each with their own specificities. The attached picture gallery illustrates scentists' activities and material during each of these "stations".
Snapshots - per station - of the intense CAML campaign
"South station" (11th, 12th and 20th of January)
Each bottle contains 3 days of resuspended sediments and plankton rain accumulation (bottles n° 4 & 5 were not used).
"West station" (13th and 16th of January)
The animal held by Marzia is a sea-cucumber, or holothurian (a group related to starfish). This is a very a special one: Scotoplanes globosa, an abyssal species !
To Julian's surprise (Julian is the group's expert onboard), the Scotoplanes globos was first spotted at 250m depth, right in front of the glacier. It could be observed thanks to the ROV video camera, operated from the control room. This particular animal became the first indication of affinities between the deep sea fauna and animals formerly living under the now vanished ice shelf. Found over the whole area, he was cutely nicknamed "piggy" by baffled scientists...
"Central station" (14th, 15th and 17th of January)
The star of this deep station (800 meters) was this still unidentified clam, living symbiotically with bacteria using methane seeping from special locations on the ocean floor, and thus without sunlight (in contradiction with most other living organisms on Earth). Only multi-box corer", also guided by a video camera.
"North station" (18th and 19th of January)
For a reason that is still not clear, this station showed a swift recolonization process, in this case by an ascidian species known for its ability to settle down scours of the sea floor, created by icebergs. Agassiz trawl.
Larsen A (21st and 22nd of January)
Just ten days after we first failed to reach it, this time we didn't encounter any ice difficulties while steaming to this other target area of the CAML program, located North of Larsen B. The Larsen A ice shelf disintegrated in several steps starting in 1995, thus allowing for a more advanced recolonization process. This didn't prevent us from encountering a magnificent and as yet unidentified starfish also belonging to a group with deep sea affinities, and previously observed in all Larsen B habitats. The soft sediments collected by Armin and Maarten, thanks to their MUC, contained tiny organisms: copepods and nematods.
