Ecological evaluation of aquatic microorganisms role in xenobiotics transformation with the reference to the Black sea

Abstract
The present analytical review is dedicated to the current perspective of the issue of the Black sea xenobiotics pollution. The Black sea is extremely vulnerable   to pollution impact, as it is a semi-closed water-body under the influence of significant inflow from the Danube, Dnipro and Dnister rivers. According to the recent data from the UNDP EMBLAS project 80 types of organic pollutants were identified in the Black Sea water samples. Those included 17 pesticides with the concentration above the safety thresholds both in the offshore and in the coastal waters. It has been previously shown that xenobiotics’ inflow results in taxonomic and functional shift of microbial communities inhabiting aquatic environment. Microbial-mediated degradation and biological pump control the polycyclic aromatic hydrocarbons’ flux in marine ecosystems, which prevents their accumulation in the food web. The data on xenobiotics pollution in both water column and sediments is summarized in the present review. The recent studies targeting the microbial communities’ role in biotransformation and translocation of substances with xenobiotic behavior are analyzed. The significance and topicality of the case-studies focusing on aquatic microbial communities functional response towards xenobiotics’ pollution is highlighted and the Black Sea ecosystem is suggested as the plausible example for addressing the above mentioned issues