Sorting the catch
French scientists have been busy sorting, analysing and distributing thousands of invertebrate and fish specimens collected between Terre Adélie and George V Land in East Antarctica.
Once the samples were entered into the MNHN databases, they were progressively sent to specialists in museums and institutions all over the world (Australia, France, Germany, USA, UK, Belgium, Chile and South Africa) where they are now being studied. The data obtained from these studies are being shared through the Marine Biodiversity Information Network of the Scientific Committee on Antarctic Research (SCAR-Marbin). This work will contribute to a substantial increase in Australian and French national collections.
The analyses of the collections are already well advanced. While molluscs, crustaceans, cnidarians and pycnogonids are still being identified, studies of some other groups are almost complete:
- All the sea squirts have been analysed, resulting in 33 species being recognised, including three new deep water species.
- All sea stars have been entered into the MNHN databases, photographed and sequenced.
- Of the more than 1000 feather star specimens collected, all have been sequenced, and five species of feather stars have been identified.
- Nineteen species of sea urchins have been identified, including two very rare, deep water ones.
- Of the 2500 teleost (bony) fishes caught, 530 have been photographed and sequenced.
- Before CEAMARC, only 21 demersal fish species had been recorded in this sector, which now incorporates 67 species, including some very rare species and a new Zoarcid (an eel-like fish).
Such taxonomic and phylogenetic studies are prerequisite to any ecological study. The results from this research voyage are already, or will be, integrated into a series of wider projects encompassing biogeographic mapping of the Southern Ocean. A very precise overview of this high biodiversity and of its various assemblages should be rapidly obtained, as scientists have at their disposal accurate identification tools, complemented by oceanographic parameters, information on the substrates (such as rocks, sand or gravel), and videos and photographs. All organisms that have been sequenced will significantly enrich the Barcode of Life database (a repository of DNA sequences).
The calving of an enormous iceberg from the Mertz Glacier tongue in February this year will likely affect local ocean circulation in the CEAMARC study region. This may have a serious impact on the local marine environment, as its scouring effects will probably reach depths of 400–500 m. Contrary to similar important iceberg calvings recently observed elsewhere in Antarctica, this one has been preceded by very detailed in situ analyses of the benthic assemblages. This should allow for a precise estimate of the importance of the impact of the calving and should lead to further studies of how benthic organisms and demersal fish have responded to it.
NADIA AMEZIANE and CATHERINE OZOUF-COSTAZ,
Museum National d'Histoire Naturelle and Centre National de la Recherche Scientifique, Paris