Geological conditions of occurrence of submarine groundwater discharge in the South-Eastern Baltic
Submarine groundwater discharge is widespread in the Southern Baltic and creates specific conditions for the formation of benthic ecosystems. Groundwater has hydrochemical characteristics that are different from sea water, which is reflected in the chemical composition of bottom sediments and waters. In addition, underground runoff from the aquifers of the zone of active water exchange, along with river runoff and atmospheric deposition, can serve as a significant factor in the pollution of the marine environment. However, the Russian sector of the Southeast Baltic is very poorly studied in relation to submarine discharge. Meanwhile, the features of the geological structure can contribute to the development of this process. The study of the geological prerequisites for submarine discharge became the goal of this work. Analysis of various factors that potentially contribute to submarine discharge (fault tectonics, seismic activity, rock permeability, paleo-incisions, pockmarks) made it possible to identify areas of the bottom that are promising for further research. In the coastal zone, this is an area of bedrock outcrops on the northern underwater slope of the Kaliningrad Peninsula, forming a Paleocene-Eocene aquifer. On the rest of the bottom area of the Southeast Baltic, aquifers are overlain by a thick layer of Quaternary formations. Only a combination of these factors makes possible the submarine discharge of groundwater at great depths of the sea.