An integrative approach to unravel the ocean's biological carbon pump (CarbOcean)

The ocean’s biological carbon pump plays a crucial role in storing atmospheric carbon dioxide in the deep ocean, thereby isolating carbon from the atmosphere for decades to centuries. Yet, its capacity to do so is under-constrained and its mechanisms poorly understood. CarbOcean will develop a mechanistic and quantitative understanding of the biological carbon pump using a novel integrative approach that accounts for its two component pumps: (1) the organic carbon pump, which concerns the photosynthetic production of particulate organic carbon and (2) the carbonate pump, which concerns the production of particulate inorganic carbon. These pumps have opposite effects on the ocean-atmosphere exchange of carbon dioxide. CarbOcean will develop a new optical sensor for autonomous measurement of calcium carbonate, empowering a unique robotic approach to quantify the two key components of the biological carbon pump and physicochemical parameters from the well-lit surface ocean through the underlying twilight zone (roughly 100 – 1000 m depth) at high spatiotemporal resolution. The robotic profilers will be deployed in a wide variety of oceanic environments and biogeochemical conditions and the collected data will allow investigation of links between the fluxes of organic and inorganic carbon particles and detection of environmental drivers. New parameterizations of carbon flux processes will be developed and implemented in a biogeochemical model. Lastly, we envision to up-scale carbon fluxes to the global ocean using remote sensing and artificial intelligence approaches.