RETAKE II

The RETAKE II project deepens the investigations started in the first project phase on the potential, feasibility and side effects of atmospheric CO2 removal by alkalinity enhancement. Alkalinity enhancement reduces the activity of CO2 in seawater, which can promote the gas exchange between the atmosphere and the ocean and thereby reduce atmospheric CO2 concentrations. A range of mineral alkalinity sources and delivery modes will be investigated in terms of dissolution kinetics, stability of added alkalinity, CO2 removal potential, and chemical and biological side effects. The process of added alkalinity will be investigated under realistic conditions for benthic and pelagic systems in laboratory and mesocosm experiments. The focus of the research is on the North Sea and Baltic Sea, while tropical coastal waters will also be examined in collaboration with India. In addition, wastewater treatment applications carried out by national cooperation partners will be scientifically accompanied with regard to the stability of the alkalinity introduced and the planning of possible field experiments.

In addition to numerical models that simulate the deployment of enhanced alkalinity in German territorial waters and other marine areas and extrapolate local experimental results to regional and global scales, the project is supplemented by a socio-economic analysis of possible effects on fish stocks and fisheries. The Center for Ocean and Society is investigating how existing uncertainties regarding the ecological impacts of alkalinity enhancement can be taken into account in fisheries management.

Project partners: GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel, Alfred-Wegener-Institut/ Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), Helmholtz-Zentrum Hereon, Leibniz-Institut für Ostseeforschung Warnemünde (IOW), Leibniz-Zentrum für Marine Tropenforschung (ZMT), Universität Bremen, Universität Hamburg (UHH), Universität Kiel (CAU).