Is today yesterday or already tomorrow? Hard to tell sometimes. It is daytime, isn’t it? Anyway, some time in the evening the first box corer brought a nice piece of sea floor onto the deck. A quarter of a square meter of a sandy something garnished with a few brittle stars. Could be from any place, but isn’t: in front of us is the first sea-floor sample from the plateau below the summit of Maud Rise, a solitary mound rising some 3,000 m from the Weddell abyssal plain. Still 2,000 m below the surface. An island in the vastness of the deep, so-to- speak. And possibly an oasis of life? The sand turns out to be a foraminiferan graveyard. Foraminiferans are single-celled animals with hard shells which can accumulate to thick sediment layers. And in it there are lots and lots of small bivalves and even gastropods. This is good news for the mollusc specialists who have not exactly been spoiled with an overabundance. Where there are many bivalves, sufficient nutrition must be available for filtering in the water column or the sediment. Our colleagues the oceanographers will explain to us that we are in the center of the Maud Rise gyre. Plankton and detritus could accumulate here.
Such thoughts, meandering while I turn over sand grains that are not even real sand, are interrupted instantly: the next quarter of a square meter is coming on deck. Waterproof clothes, rubber boots and hard hat on, a little exercise in the fresh air: filtering and washing of sediment with freezing cold sea water, transferring samples into containers, scrubbing the deck. Everything works like a machine, the team is well organised. It is neither bright nor dark, must be after midnight. Sorting skeletons yet again. This was much more exciting a few hours ago. But all animals have to be picked out of the sediment before they deteriorate. It is amazing in any case that the critters are still alive. They just came from a depth of 2000 m to the surface, where the pressure is just 1/200th as high.
The station monitor announces the big Agassiz trawl for 5 o’clock in the morning. Not worth going to sleep. Better keep up the caffeine level. At four a.m. the time has already come. A dozen large tubs are standing there for the awaited masses of mud. We expect long hours of washing until the very last sediment particle has been passed through a 0.5-mm sieve. Well, nothing of that kind happened: the cod end is hanging rather sluggishly from the huge steel frame. Upon opening, a few fish, sea urchins and some 17 kilos of sea cucumbers fall on the deck. But not just your normal sea cucumber! These ones are true monsters. These creatures, nearly 1 meter long and as thick as a seman’s upper arm, plough through the seabed with open mouths, digest what little biomass there is in the sediment and dispose of the rest at the other end. That’s how simple the life of an unspecific sediment eater is. Well, not quite, evil is looming everywhere. On our cucumbers there are parasitic snails, sucking while buried deeply in the skin. Most likely new species, caught red-handed while feasting on their host!
If only a few monoplacophorans would show up, they would make my day. These limpet-like animals, minute (only 1-2-millimeters) and extremely rare, are living fossils. If at all, I would find them in the fine-meshed net of Henri’s Rauschert Dredge, a cute little steel sledge which was allowed to ride along and scrape the sea floor behind the trawl: bivalves, snails, brittle stars and myriads of protist shells. Sounds strangely familiar. Not a single little monoplac. The bivalve jar is overfilled, hands and tweezers work on remote control. I sort, therefore I am. Even without a sense of time or sleep. A little bit happy about the nice specimens. And a little bit sad because my darlings were again not present. Polarstern keeps steaming on, and some 2000 m down a few tiny beings are smiling into the eternal darkness.
Michael Schrödl, Zoological Museum Munich
Photos: T. Rielh, University of Hamburg