Living benthic foraminiferal assemblages in surface samples of the Arabian Sea

The distribution, biomass, and diversity of living (Rose Bengal stained) deep-sea benthic foraminifera (>30 µm) were investigated with multicorer samples from seven stations in the Arabian Sea during the intermonsoonal periods in March and in September/October, 1995. Water depths of the stations ranged between 1916 and 4425 m. The distribution of benthic foraminifera was compared with dissolved oxygen, % organic carbon, % calcium carbonate, ammonium, % silica, chloroplastic pigment equivalents, sand content, pore water content of the sediment, and organic carbon flux to explain the foraminiferal patterns and depositional environments. A total of six species-communities comprising 178 living species were identified by principal component analysis. The seasonal comparison shows that at the western stations foraminiferal abundance and biomass were higher during the Spring Intermonsoon than during the Fall Intermonsoon. The regional comparison indicates a distinct gradient in abundance, biomass, and diversity from west to east, and for biomass from north to south. Highest values are recorded in the western part of the Arabian Sea, where the influence of coastal and offshore upwelling are responsible for high carbon fluxes. Estimated total biomass of living benthic foraminifera integrated for the upper 5 cm of the sediment ranged between 11 mg Corg m**-2 at the southern station and 420 mg Corg m**-2 at the western station. Foraminifera in the size range from 30 to 125 ?m, the so-called microforaminifera, contributed between 20 and 65% to the abundance, but only 3% to 28% to the biomass of the fauna. Highest values were found in the central and southern Arabian Sea, indicating their importance in oligotrophic deep-sea areas. The overall abundance of benthic foraminifera is positively correlated with oxygen content and pore volume, and partly with carbon content and chloroplastic pigment equivalents of the sediment. The distributional patterns of the communities seem to be controlled by sand fraction, dissolved oxygen, calcium carbonate and organic carbon content of the sediment, but the critical variables are of different significance for each community.

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.