(Bio)geochemical Dynamics of Seawater-Aquifer Interactions: Impacts on Coastal Sediments and Ecosystem

Activity: Talk or presentationConference presentation

Description

Coastal aquifers are dynamic transition zones where fresh groundwater and saline seawater interact. In the Baltic Sea region, dense coastal populations and groundwater use affect the quality of groundwater, making coastal aquifers both vital resources and vulnerable systems. Excessive groundwater extraction and climate change may make aquifers more susceptible to seawater intrusion, lowering groundwater quality, while submarine groundwater discharges transport nutrients, carbon, and metals to the already vulnerable coastal waters (Burnett et al. 2003; Ferguson & Gleeson 2012; Luoma et al. 2015). These fluxes may strongly influence seabed and water column biogeochemistry, and their magnitude and ecological consequences in the Baltic Sea are not yet fully understood.

We investigate how seawater-aquifer interactions affect groundwater quality, sediment biogeochemistry, and coastal ecosystems in the Baltic Sea. By combining biogeochemical analyses of groundwater and sediment porewater with benthic biodiversity and trait analyses at a coastal aquifer site in Hanko, Finland (Virtasalo et al. 2019), the study will provide one of the first integrated assessments of these linkages in the region. Firstly, we will investigate potential seawater intrusion in aquifers of the Hanko coast, relevant for the protection of water resources. Secondly, we will quantify the impact of groundwater-seawater interactions on coastal sediments and local biota, as well as their relevance for the chemical load in coastal areas with aquifers. This will provide new insights about the effects of coastal aquifers on marine ecosystems and their biodiversity.
Period13 Jan 202615 Jan 2026
Event title37th Nordic Geological Winter Meeting
Event typeConference
LocationTurku, FinlandShow on map
Degree of RecognitionInternational