Cadmium influence on benthic foraminifera of the Black sea shelf (Danube delta region)

Abstract

The work is devoted to application of the benthic foraminifera for an evaluation of an geoecological situation on a northwest shelf of the Black Sea. The awake role of organisms with carbonaceous function is marked during biological absorption of toxic bonds. The attributes of stressful situations on population and organismic level include a degree of a surviving of species and morphological changes of the foraminifera. These parameters applied for abjection of geographic ranges of a toxic stimulation, development and anomalous morphology of organisms.  Purpose. The aim of this work is to analyze the effect of significant cadmium content on benthic foraminifers of the Black Sea shelf (Danube Delta region). Methods. Field studies provided for the selection, documentation and preparation of analytical samples. Micro-paleontological and lithologic-geochemical studies of bottom sediments were carried out in accordance with accepted methods. The method for studying foraminifera includes the following operations: sampling, separation, preservation and preparation for analysis, taxonomic identification, morphological analysis, biomineralogical studies and mathematical processing of results.  Results. The conducted observations confirm the possibility of differentiated assessment of  heavy metal contamination by the example of cadmium in the shelf   Black Sea. Areas of pollution are characterized by a decrease in the species diversity of foraminifera compared to uncontaminated areas. In sediments with a high content of cadmium, foraminifera are characterized by depressed forms with numerous deformities. Conclusions. A significant concentration of cadmium strongly affects the occurrence of foraminifera and the appearance of morphological anomalies in their shells.