Abundance of copepods during POLARSTERN cruise ANT-XXI/2 (BENDIX)

The main emphasis of this study was to analyse the short-term development of abundance, population structure and vertical distribution of the dominant calanoid copepods during a phytoplankton bloom in the coastal area of the eastern Weddell Sea in December 2003. Microcalanus pygmaeus was by far the most abundant calanoid species. Metridia gerlachei, Ctenocalanus citer, Calanoides acutus, Calanus propinquus and the ice-associated Stephos longipes were also present in considerable proportions. The observed changes in the population characteristics and parameters of these species are described in detail and discussed in the context of the spring phytoplankton bloom. A conspicuous event occurring during the final stage of the study was the development of a strong storm. While the results suggest that this storm did not have any considerable influence on the populations of all other investigated copepod species, it very likely caused pronounced changes in the S. longipes population present in the water column. Before the storm, S. longipes was found primarily in the upper 100 m of the water column, and its population was dominated by adults (mean proportion = 41%) and the copepodite stage I (mean proportion = 30%). After the storm, the abundance increased considerably, and the copepodite stage I contributed by far the largest proportion (53%) of the total population indicating that the early copepodite stages probably had been released from the sea ice into the under ice water layer due to ice break-up and ice melt processes caused by the storm.

The Global Plankton Database: an inventory and data from the Former Soviet Union expeditions

At present time, there is a lack of knowledge on the interannual climate-related variability of zooplankton communities of the tropical Atlantic, central Mediterranean Sea, Caspian Sea, and Aral Sea, due to the absence of appropriate databases. In the mid latitudes, the North Atlantic Oscillation (NAO) is the dominant mode of atmospheric fluctuations over eastern North America, the northern Atlantic Ocean and Europe. Therefore, one of the issues that need to be addressed through data synthesis is the evaluation of interannual patterns in species abundance and species diversity over these regions in regard to the NAO. The database has been used to investigate the ecological role of the NAO in interannual variations of mesozooplankton abundance and biomass along the zonal array of the NAO influence. Basic approach to the proposed research involved: (1) development of co-operation between experts and data holders in Ukraine, Russia, Kazakhstan, Azerbaijan, UK, and USA to rescue and compile the oceanographic data sets and release them on CD-ROM, (2) organization and compilation of a database based on FSU cruises to the above regions, (3) analysis of the basin-scale interannual variability of the zooplankton species abundance, biomass, and species diversity.