Перспективные методы обнаружения субмаринной разгрузки в Балтийском море и опыт их применения

Abstract

Submarine discharge of groundwater (SDGW) is a hydrological process that typically occurs in coastal areas and is defined as the underwater inflow of fresh and brackish ground­water from the continent to the sea. The discharge of waters with a composition sharply differ­ent from seawater leads to the formation of hydrochemical anomalies in the near-bottom hori­zon and alters the composition of bottom sediments. Under different regional conditions, dis­charge can occur as a focused flow through cracks in karst and fissured rocks, as a diffuse flow in loose deposits, or through the recirculation of seawater in bottom deposits. Therefore, it is essential to consider local geological and hydrogeological conditions, as they can significantly influence the character and distribution of groundwater and, consequently, the possibility of submarine discharge and the likelihood of its detection. Despite the ubiquity of the SDGW process in the continental shelf zone, practical detection is often a challenging task. The aim of this study is to identify approaches that best allow for documenting the phenomenon of sub­marine discharge of groundwater in the southeast part of the Baltic Sea. Detecting submarine groundwater discharge in the Baltic Sea is crucial for understanding the processes in the wa­ter body and evaluating the ecological situation. The study examines various methods for detecting SDGW: computational-analytical, geophysical, radioisotopic, chemical, and biologi­cal. The expe­rience of their application in the southeastern Baltic Sea is characterized, allow­ing for the identi­fication of areas where submarine discharge of groundwater from Jurassic and Cretaceous hori­zons occurs. The conclusion is drawn that for effective detection of sub­marine discharge foci, a comprehensive approach involving various research methods is neces­sary.