Author: Catia Milene  Ehlert von Ahn,   (Leibniz Institute for Baltic Sea Research Warnemuende (IOW)

Designation: 

Description:
Geochemical tracers indicated large-scale groundwater discharge to the seas and oceans through diffusive and advective processes, however, our knowledge on the areas and causes of submarine groundwater discharge (SGD) along the coastlines is still limited. Here we present results of a combination of geochemical and geophysical surveys carried out in the urbanized Wismar Bay (WB), southern Baltic Sea. Areas of elevated radium and radon isotope activities suggested the influence of SGD on WB. The hydro-acoustic sediment profiles show that the bottom sediments in the central bay are under local impact of excavation. The impact of the excavation reduced the sediment thickness of the aquitard and partially exposed normally buried geologic units to the seafloor, promoting freshwater discharge. Geochemical sediment porewater data from the central part of the bay identified freshened porewater, with water isotope composition close to the local meteoric water line defined for the southern part of the German Baltic Sea, suggesting a discharge of relatively modern freshwater. The results obtained so far indicated that artificial infrastructures, like sediment channeling, may ease the hydrological connection between coastal aquifer and coastal bottom water increasing SGD at coastal urbanized areas.   The investigations are supported by the DAAD, DFG RTS Baltic TRANSCOAST, BONUS SEAMOUNT, FP7 EU Marie Curie career integration grant, DAM-MFG, and IOW.

Category: Scientific Program Abstract > Special Sessions > SS36 Groundwater-surface water exchange across the land-ocean continuum