Estimation of submarine groundwater discharge metal fluxes to the coastal Mediterranean Sea
The purpose of the project is to investigate the input, dispersion and role of trace metals (Fe, Zn, Cu, Ni, Pb, Co, Cd), released to the Mediterranean Sea with Submarine Groundwater Discharge.
SGD is the input of subterranean water (fresh groundwater mixed with salty recirculating seawater) to the sea on continental margins; it is considered an important source of nutrients and metals, so that it can affect the biogeochemistry of the coastal environment and the metal oceanic budgets. In the case of the Mediterranean Sea, SGD could have even a higher relevance than in other contexts, because of the limited riverine inputs and the small recirculation processes due to the weak tidal pumping. With this project, fluxes of trace metals driven by SGD will be investigated in some Mediterranean areas, characterizing also chemical elements and isotope behaviours in the subterranean mixing zone, where several biogeochemical processes occur, affecting the composition of the water discharging into the sea.
The starting point to determine metal fluxes is the quantification of SGD by means of Ra-isotopes (223Ra, 224Ra, 226Ra, 228Ra) and 222Rn. By determining their activity in water samples and using mass balance models, it is possible to obtain SGD flux values, which in combination with metal concentrations, conveniently measured, can be used to estimate metal fluxes.
The work will be carried out in different locations.