Evidence for Submarine Groundwater Discharge into the Black Sea-Investigation of Two Dissimilar Geographical Settings

The sustainable management of coastal marine environments requires a comprehensive understanding of the processes related to material transport from land to coastal sea. Besides surface water discharge (e.g., rivers and storm drains), submarine groundwater discharge (SGD) plays a key role since it provides a major pathway for solute and particulate transport of contaminants and nutrients, both having considerable potential to cause deterioration of the overall ecological status of coastal environments. The aim of the presented study was the investigation of SGD in two exemplary and dissimilar areas at the Black Sea coast, one in the west (Romania) and one in the east (Georgia). The approach included the assessment of the geological/geographical setting regarding the potential of SGD occurrence, the use of environmental tracer data (Rn-222, delta O-18, delta H-2, salinity), and the evaluation of sea surface temperature patterns near the coastline using satellite data. Besides the individual site specific results, the study revealed that a combined evaluation of tracer data and satellite based information allows SGD localization with satisfying precision. A downscaling approach starting with large scale satellite data is generally recommended, continuing with medium scale tracer patterns and ending with local spot sampling.