Hydrogeology and Landscape Hydrology

BIME: Assessment of ground- and porewater-derived nutrient fluxes
into the German North Sea - Is there a "Barrier Island Mass Effect (BIME)"?

Project summary

In the past three decades, submarine groundwater discharge (SGD) has been recognized as a major pathway for nutrients and trace metals. It can influence benthic community structures and trigger harmful algal blooms. Still, little is known about the physical, chemical and biological processes in the benthic boundary layer and surface sediments, where fresh groundwater and recirculating seawater are mixing and discharging. Also, the periodic and episodic dynamics of SGD in the coastal ecosystem are not well understood. In this novel interdisciplinary approach, the basic processes governing SGD dynamics, composition, and interaction with associated biota will be studied. Three groundwater-dominated barrier islands in the German North Sea (Mellum, Norderney, and Spiekeroog) with similar geology and climate, but different anthropogenic impacts, will be compared with regards to the magnitudes, biogeochemistry, and ecology of SGD. In the BIME project several working groups of the ICBM and the Max-Planck-Institute cooperate, and it is coordinated by the ICBM-MPI Bridging Group for Marine Geochemistry (ICBM). Our role in this project is to develop numerical models to quantify the SGD magnitudes over tidal and seasonal time scales. Further tritium/helium groundwater ages in the freshwater lenses and along the investigated beach transects will be measured in order to support model calibration as well as to provide important information about groundwater travel times.

Cooperation

Biogeochemistry Group, Max-Planck Institute for Marine Microbiology (MPI), Bremen
Hydrogeology and Landscape Hydrology Group, Institute for Biology and Environmental Sciences (IBU), University of Oldenburg
ICBM-MPI Bridging Group for Marine Geochemistry (ICBM), University of Oldenburg
Isotope Geochemistry Group (ICBM/MPI), University of Oldenburg, Germany
Marine Sensor Systems Group (ICBM), University of Oldenburg
Microbiogeochemistry Group (ICBM), University of Oldenburg
Paleomicrobiology Group (ICBM), University of Oldenburg

Financing

Niedersachsisches Ministerium für Wissenschaft und Kultur

Project duration

May 2015 - April 2020

Persons in charge