Freshwater detected beneath the seafloor of the Corinthian Gulf

Researchers from universities and research centers in Malta and Italy focused their attention on the Corinthian Gulf, “ one of the most thoroughly studied regions of the Mediterranean in terms of tectonic activity and sediment deposition,” explains Senay Horozal, lead author of the study, in an interview with the Athens-Macedonian News Agency (ANA-MPA).

“ It is a geologically active rift basin with a high rate of sediment accumulation that has experienced significant sea-level fluctuations over the past hundreds of thousands of years - factors that make it an ideal natural laboratory for studying how coastal low-salinity groundwater systems form and are preserved,” she added.

In the study, published in the Hydrogeology Journal (the journal of the International Association of Hydrogeologists), the team identified and mapped coastal low-salinity waters stored in sediments beneath the Corinthian Gulf. Findings indicate that during glacial periods, major sea-level drops allowed rainwater and river water to infiltrate coastal and submarine sediments - part of which has been preserved to this day.
The low-salinity water is found at depths ranging from about 20 to 600-700 meters below the seafloor in the central basin of the Corinthian Gulf, and from 15 to 150 meters below the seabed in the eastern Alkyonides area. The lateral sediment layers in the basin may contain up to approximately 250 cubic kilometers of this subsurface water.

Greece, like many Mediterranean countries, faces increasing pressure on its water resources, so mapping the locations of these underground water bodies and understanding how geological structures protect them can give the state a clearer picture of the subsurface. Horozal underlined that: “ In the context of climate change and rising demand for freshwater, knowing where these low-salinity water bodies are and how much water they may contain is crucial for long-term water management strategies.” However, she also said that "any potential exploitation should be approached with great care, given the environmental sensitivity of coastal systems."