The global ocean is the major natural sink for carbon, nutrients and other biologically active substances. Most of the anthropogenic CO2 will ultimately be removed from the atmosphere and transferred into the oceans to be stored as dissolved inorganic carbon in seawater and particulate organic and inorganic carbon in marine sediments. The uptake rate of atmospheric CO2 is determined by the efficiency of the physical and biological marine carbon pumps transferring CO2 to the ocean’s interior. Climate engineering (CE) approaches have been proposed to stimulate these natural CO2 pumps. They aim at exploiting the vast nutrient inventory of the oceans to sequester additional CO2 as in the form of marine biomass or intend to employ the buffering capacity of seawater to neutralize CO2. Geological formations below the seabed have already been used to dispose CO2 recovered from offshore natural gas production for more than a decade and a large number of new storage sites below the seabed will be opened in the near future to accommodate CO2 from coal-fired plants. Marine CE options and sub-seabed CO2 storage may help to mitigate future climate change but could also amplify ongoing ocean acidification and oxygen loss in the ocean with potentially grave and harmful consequences for marine ecosystems. By combining perspectives of disciplines relevant to the subject, the research topic Ocean Sinks aims for an unbiased assessment of these marine carbon sequestration techniques (MCST ).
The research will be organized along three lines:
Focus 1 investigate sub-seabed storage of CO2.The project will provide a comprehensive evaluation of different sub-seabed storage options including enhanced oil and gas recovery and storage in saline aquifers, depleted oil and gas reservoirs, deep-sea sediments, gas hydrates and oceanic crust.
Focus 2 investigates the marine CE options: Artificial upwelling and ocean iron fertilization may stimulate biological CO2 sequestration while the physical and chemical uptake of CO2 in the ocean could be enhanced by dissolving alkaline rocks and minerals in seawater.
Combining both foci, Focus 3 concentrates on designing potential global MCST portfolios.