Descrizione del progetto
Gira e rigira: gli scienziati trovano un nuovo proxy per aiutare a monitorare il ciclo del carbonio
Il ciclo globale del carbonio, in cui il carbonio viene scambiato tra i serbatoi dell’atmosfera, degli oceani e della terra, svolge un ruolo attivo nel clima della Terra. Gli oceani possono assorbire una quantità enorme di CO2 e gli organismi marini sono fondamentali per questo processo attraverso la pompa biologica del carbonio. In superficie, i fotosintetizzatori come il fitoplancton trasformano la CO2 disciolta in carbonio organico, di cui la maggior parte viene riconvertita in CO2 attraverso la respirazione di animali, piante e batteri, per rientrare successivamente nell’atmosfera in scale temporali brevi. Quando le piante e gli animali muoiono, ne trasportano una piccola frazione con loro nelle profondità della terra, dove la decomposizione la rilascia lentamente. La pompa biologica del carbonio svolge un ruolo cruciale nei processi climatici, un aspetto tuttavia poco compreso. Il progetto SCrIPT, finanziato dall’UE, sta elaborando un proxy per valutare i cambiamenti della pompa biologica del carbonio nel tempo, sia passati che futuri.
Obiettivo
The overall concept of this proposal is to investigate the main biogeochemical processes modulating spatial and temporal changes in marine export productivity, and assess their role in regulating atmospheric carbon dioxide (CO2) concentrations, both under present conditions and in the geological past. The exchange of CO2 between the atmosphere and ocean interior mediated by the oceanic ecosystem is a pivotal mechanism modulating the global carbon cycle, and thus, a substantial driver of the Earth’s climatic evolution.
The overarching objective of this research proposal is to develop a novel proxy to trace changes in the global strength of the marine biological carbon pump (BCP) based on stable Chromium (Cr) isotopes. Despite its significance for the global carbon cycle, the BCP is still poorly constrained. This project will explore a tracer that has recently been developed to investigate the rise of atmospheric oxygen in the early history of the Earth and develop it thoroughly through a comprehensive, multidisciplinary calibration program and apply it to the much more subtle redox variations associated with organic matter remineralization in the ocean. The proposed approach includes phytoplankton culture experiments, water-column investigations and sedimentary analysis and will aim at elucidating the mechanisms governing the reduction of Cr and its associated isotopic fractionation. The proxy will subsequently be used to reconstruct export production variability in the past and assess its role in modulating glacial/interglacial climate oscillations. These past changes tended to be much slower than the current, anthropogenic change. Nonetheless, they can help to appraise sensitivities and point toward potentially dominant mechanisms of change. The observations gathered within the framework of this research program will enable refining the evolution of the marine carbon cycle and the rapidly declining buffering capacity of the ocean.
Campo scientifico
- humanitieshistory and archaeologyhistory
- natural scienceschemical sciencesinorganic chemistrytransition metals
- social scienceseconomics and businesseconomicsproduction economicsproductivity
- natural sciencesbiological sciencesecologyecosystems
- natural sciencesearth and related environmental sciencesatmospheric sciencesclimatologyclimatic changes
Parole chiave
Programma(i)
Argomento(i)
Meccanismo di finanziamento
ERC-COG - Consolidator GrantIstituzione ospitante
1015 LAUSANNE
Svizzera