Polarstern / CAML expedition: first biological samples from the seafloor
Biologists at work
© G. Chapelle / IPF / Alfred Wegener Institute
Finally some work for the benthos (organisms living on the bottom) fanatics: this afternoon, we had our first Agassiz trawl on the deck. After having scoured the bottom 300 m below, the net brought back a typical sample of sponge communities, quite common in Atka Bay. These sponges dominating the underwater landscape are big (up to 60 cm high) and robust, thanks to their silica skeleton, which is nothing but glass, synthesized in the freezing water.
Considered as the most primitive animals, sponges attract a lot of other groups, they are a perching place for other filter feeders like sea cucumbers or brittle stars (starfish with thin and highly motile arms), and a shelter for fish, shrimps or amphipods.
Once poured on the working deck, the net content had lost its color, and would attract very few people. But biologists love it. We haven't seen them smiling like this for a long time ! They take possession of this brownish mass to pick out their favorite critters. The sea urchins for Thomas, the mollusks for Olaf, the fish for Karel, the corals for Pablo, the polychetes (group of marine worms) for Americo, the isopods (marine wood lice) for Meike, nearly everyone gets a share ! Some groups are still missing, like Elaina and Iain's octopuses, but it is only our first station. A few amphipods in there as well, of course ! After footage and pictures, I couldn't help myself and dived in with Cédric and Henri to harvest our favourite beasties...
