Global space-time variability in primary production and carbon flux using the Argo float network

Global climate change is predicted to alter the ocean's biological productivity with implications for fisheries and climate. Long-term changes in phytoplankton abundance projected by ocean coupled physical-biogeochemical models predict declining globally averaged phytoplankton abundance, associated carbon fluxes, and widespread deoxygenation (Kwiatkowski et al., 2020). However, observational data that could be used to verify current climate trends is limited in both space and time, particularly below the ocean surface. The advent of the bgc-Argo programme (https://biogeochemical-argo.org/) has vastly increased the quantity of biogeochemical data available for analysis (currently > 1500 floats have been deployed since 2002). The data are, however, scattered in space and time, making it difficult to deduce either the global mean 3-D distribution of biogeochemical properties, or how they may change seasonally or from year to year. This results in some fundamental gaps in our knowledge of contemporary ocean biogeochemistry, and the potential future response to climate change. For example, what is the global distribution of the subsurface chlorophyll maximum? How does the efficiency with which particulate organic carbon is stored in the ocean vary globally (e.g. Dall'Olmo and Mork, 2014)? This project aims to exploit the full potential of the bgc-Argo network to answer these questions by using space-time modelling (Hammond et al., 2017) to infer global spatial and temporal variability in critical biogeochemical processes.