Project description
Mapping the role of diazotrophs in the carbon cycle
Diazotrophic microorganisms help regulate the world’s marine productivity by converting nitrogen and contributing to carbon sinks, but we don’t know how much diazotroph-derived carbon is exported to the deep ocean. The EU-funded HOPE project seeks to find out, enabling better predictions about the ocean’s role in sequestering CO2 and mitigating climate change. Using single-cell isotopic techniques, researchers will examine this prokaryotic carbon pump to map its transient and seasonal features. An experimental water column will also allow researchers to determine how diazotrophs aggregate, sink and are remineralised, and an autonomous measuring platform will monitor how environmental drivers control the efficiency of the pump. This will result in new global estimates for carbon exported by diazotrophs.
Objective
Diazotrophs regulate marine productivity in 60% of our oceans by alleviating nitrogen limitation, contributing to carbon (C) sequestration through the N2-primed Prokaryotic C Pump (PCP). Yet we don’t know how much diazotroph-derived organic C (OC) is exported to the deep ocean, which prevents robust predictions of how the ocean contributes to CO2 sequestration and climate change mitigation. This knowledge gap is due to the multiple and complex pathways by which diazotrophs are exported to the deep ocean, which quantification and drivers of variability are impossible to capture with current methods. HOPE will bridge this gap thanks to a new isotopic technique I developed and to a coupling between lab and in situ approaches examining processes occurring at different spatiotemporal scales, and capable of capturing both transient and seasonal features of the PCP. HOPE will: 1.Determine how various diazotrophs aggregate, sink and are remineralized by using an automated experimental water column I designed for this proposal 2.Decipher by which pathways diazotroph-derived OC is exported to the deep ocean thanks to a pioneer approach combining single-cell isotopic analyses, in-depth microbiological characterization of sinking particles and geochemical budgets 3.Investigate how environmental drivers control the whole process, from the surface diazotroph community up to their eventual export to the deep ocean, by deploying a cutting-edge autonomous platform, unique as it performs synoptic measurements both in and below the euphotic zone at high resolution (hourly/daily). In its final stage, HOPE will use the generated data to provide global, spatially resolved estimates of the contribution of diazotrophs to overall OC export. Based on my expertise at the interface between microbial oceanography and geochemistry, HOPE has the potential to deliver a multidisciplinary and ground-breaking knowledge leading to potential scientific-based recommendations to fight climate change.
Fields of science
- natural sciencesearth and related environmental sciencesgeochemistry
- social scienceseconomics and businesseconomicsproduction economicsproductivity
- natural sciencesbiological sciencesecologyecosystems
- natural sciencesearth and related environmental sciencesoceanography
- natural sciencesearth and related environmental sciencesatmospheric sciencesclimatologyclimatic changes
Programme(s)
- HORIZON.1.1 - European Research Council (ERC) Main Programme
Funding Scheme
HORIZON-AG - HORIZON Action Grant Budget-BasedHost institution
13572 Marseille
France