Iron cycling in continental margin sediments and the nutrient and oxygen balance of the ocean

• Applicant: Professor Dr. Florian Scholz
• Subject Area: Oceanography ; Mineralogy, Petrology and Geochemistry
• Term: from 2016 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 283168947

The ICONOX research group evaluates a novel concept according to which sedimentary iron cycling controls the ocean’s nutrient and oxygen balance. Iron is an essential micronutrient and commonly regarded as the key‐limiting factor for primary production, carbon export and respiratory oxygen consumption in the ocean. The currently observed trend of ocean deoxygenation as a consequence of global warming promotes dissolution of iron minerals at the seafloor and the resulting increase in iron supply to the ocean may fuel nitrogen fixation, primary production and further oxygen drawdown in a positive feedback loop. In contrast, notorious iron enrichments in sediments of anoxic and sulfidic settings in the geological record indicate that under conditions of extreme ocean anoxia, marine sediments turn into a highly efficient sink for bioavailable iron. The switch from iron release to iron retention and burial likely represents an important, yet poorly constrained linchpin in the long‐term cycles of nitrogen and carbon in the ocean. Within the ICONOX project, observational, experimental and numerical approaches are applied to constrain the role of sedimentary iron burial and release in ocean biogeochemical dynamics, today and through Earth’s history. Within the framework of a 12-months extension of the project, it is planned to investigate the influence of chemical weathering, both on land and in the ocean, as well as coastal erosion on the marine biogeochemical cycles of iron and other elements.

• DFG Programme: Independent Junior Research Groups