FORAMINIFERA AS INDICATORS OF ENVIRONMENTAL STRESS IN MARINE ECOSYSTEMS: NEW EVIDENCE FROM THE ROMANIAN AND UKRAINIAN SHELF (BLACK SEA)

The first European application of a study of benthic foraminifera and bottom sediment lithology to trace the influence of Danube freshwater discharge on the benthic ecosystems of the Black Sea Romanian and Ukrainian shelf is being conducted within the framework of the international project BS-ERA.NET 076 “Water Pollution Prеvеntion Options for Coastal Zonеs and Tourist Arеas: Appliсation to thе Danubе Delta Front Arеa,” WAPCOAST (2010-2012) and “Control of observation during the operation of deep water navigable course of the Danube-Black Sea: sea part" under agreement No. 40/13 with the Ukrainian Scientific Research Institute of Ecological Problems, Kharkov. The main goal is to measure environmental stress in marine bottom ecosystems caused by river discharge using bathymetric succession of benthic foraminifera as indicators. Tis presention will show that the study area of the Black Sea shelf adjacent to the Danube delta is under permanent environmental stress. Alternation of foramininferal assemblages A. ammoniformis-A. compacta-A. tepida and disappearance of polyhaline Lagenida in shoreward assemblages suggest that salinity is the leading factor in the stress. Other factors, e.g., eutrification and oxygen depletion, may play a secondary role, while type of substrate does not contribute significantly to distribution of species. The latter is unusual and contradicts other findings. Also, there is little evidence to indicate that Danube River input of water and sediments contributes greatly to development of morphological abnormalities in foraminiferal tests. Apparently, salinity is not a major factor here either because salinity variations in the study area are minimal for Ammonia and Porosononion, which, being holeuryhaline genera, are well adapted to salinity variations.