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The Antarctic Ocean floor

05.09.2005

The biodiversity of the seas and the ocean floors is a mystery for science yet to unravel. With this curiosity, a research team – including a biologist from the University of the Basque Country, is to set sail for the second time on an oceanographic campaign to study this biodiversity of the seas and the ocean floors of the Antarctic.

Bellingshausen Sea

The expedition, aboard the oceanographic vessel, Hesperides, will shortly be working in the Bellingshausen Sea. The reason why these waters have remained almost unexplored is due to its adverse climate which, in turn, has assured that human presence has been scarce.

On this present campaign the scientists will trawl the ocean floor at up to 2000 metres depth, using both Agassiz-trawl fitted with a closed net as well as a Box-corer.

The two methods are complementary. With the Agassiz-trawl a corridor of the sea floor is swept to catch all the species on the way in a mixed form. On the other hand the Box-corer is cast and once it hits the bottom it takes a 50cm x 50cm sample thereof for subsequent analysis on deck. With this sample we can quantify the number of each species per square metre, its biomass, and so on. Thus it is known as a quantified sample of the ocean floor.

When the samples arrive on deck they are washed and classified on board in large groups or rows: sponges, corals, polyquets, molluscs, echinoderms, fish, etc. and are photographed so that their colour when alive and external anatomy can be clearly appreciated. Finally, they are inserted in alcohol or formaldehyde for their subsequent analysis in the laboratory.

Identification of a new species

Once the animals get to port they are distributed amongst the specialists according to their group. In our case, at the Leioa campus of the University of the Basque Country in Bizkaia, two groups of vermes or sea worms are taxonomically analysed. The aim of this is to identify the species, to find out if they are new species or belong to previously described ones.

To this end, both the external and the internal anatomy of the animal are thoroughly analysed, using hand-lens and microscope. It should be pointed out that these animals measure between 1mm and 150mm.

In the laboratory itself photographs are again taken in order to identify features peculiar tot he animal and, finally, the classification of the species in question is presented in the specialist literature.

In the previous campaign, expedition members discovered a new species of vermes. The name of the species and its morphological characteristics will shortly be put forward for approval by the scientific community.

Thus, this exciting task of analysing the biodiversity of the marine floor is, little by little, bearing fruit. We trust that it is not too late, given that the experts claim that many species are disappearing – even before we know about them.