Photo: Getting ready to deploy the Agassiz trawl in the snow, by J. Strugnell BASBy Jan strugnell, British Antarctic SurveyWe have been incredibly lucky that the ice conditions have allowed us to enter Pine Island Bay, (in the Amundsen Sea) to carry out the BIOPEARL sampling programme as planned. In many previous years, Pine Island Bay has been inaccessible, due to a thick ice sheet, and so we are very fortunate that it is open at this time.
Literally nothing is known of the benthic fauna of the Amundsen sea, south of latitude 66° south, because no one has sampled here previously. Therefore anything we find here is a new record of a species in this area!
Photo: Sieving samples from the Agassiz trawl in the snow, by Jan Strugnell, BAS
We have had a very busy few days (and nights!) on board completing our sampling protocol. We sampled replicates at 1500 m, 1000 m and 500 m depth using both the Agassiz trawl, which samples the life on the sea floor, and the Epibenthic sledge, which samples life just above the sea floor. We also took a CTD (conductivity, temperature and depth) at each site, to build up a profile of water parameters at these depths and also to collect bacteria from the water column. We also used a box corer to sample the top 30 cm or so of the sea floor to be able to sample the burrowing animals which live within the it.
Photo: A collection of sea urchins caught in a Agassiz trawl, by J. Strugnell BAS
Without a doubt the sea floor of the region of Pine Island Bay where we have been sampling is incredibly muddy. The mud is made up of incredibly fine grained particles and the mud itself is incredibly gooey and it sticks to all the animals within the catch (and us too!). After every trawl we have had to sieve the catch and wash it down with sea water to liberate the animals from the huge volumes of mud. This has been a very labour intensive task, but everyone has helped out and has got very muddy in the process!
Photo: catch from the Agassiz trawl, from Pine Island Bay, by J. Strugnell BAS
So far we have seen representatives of most of the major groups of animals known from Antarctic waters; including various kinds of fish, (many with strange adaptations such as long spines to hold them above the muddy sea floor), large sponges (sometimes up to 0.5 m in length!) molluscs (we have had representatives of octopus, bivalves, snails, tusk shells and chitons), echinoderms (sea urchins, sea cucumbers, brittle stars and star fish), crustaceans (isopods, amphipods, krill and other prawn like animals), corals, bryozoans and various kinds of worm-like creatures (including polychaetes, nematodes, nemertean worms, sipunculids and echiurans).
Photo: Adrian Glover with a sponge, caught in a Agassiz trawl from Pine Island Bay, by J. Strugnell BAS
Photo: Jan Strugnell with a sea urchin (holothurian) caught in a Agassiz trawl from Pine Island Bay.
Everything we catch is carefully photographed as quickly as possible to aid in later identification. Tissue samples are then taken for DNA and RNA analysis and some DNA extractions are performed immediately on board. All the animals we catch are preserved and are brought back to the UK for identification and further analysis.
The catches from 500 m depth tend to have a lot higher numbers and diversity of animals than those from the deeper depths. We are now about to begin our second set of sampling within Pine Island Bay at 500m and although we are all quite tired, we are pretty excited to see what the next catch will bring!
From February 19th until April 10th 2008, British scientists are embarking on the British Antarctic Survey’s (BAS) research ship RRS James Clark Ross. This project is part of the BAS program known as BIOFLAME (Biodiversity, Function, Limits and Adaption from Molecules to Ecosystems). Scientists onboard are studying marine fauna from the ocean shelves and slopes from a little-known region, the Bellingshausen and Amundsen Seas. This is part of the Census of Antarctic Marine Life. Follow their route on the CAML-Cousteau Expedition tracking page.