Joint Seminar: Oceanic CO2 outgassing triggered by terrestrial organic matter fluxes during the last deglaciation

Ocean is the main carbon reservoir and has acted over the past glacial/interglacial cycles as sink or source of carbon to the atmosphere. During the last deglaciation (~21 to 10 ka - thousand years before present), the melting of ice sheets and associated sea-level rise of about 95 m led to the flooding of land coastal areas and to the transfer of terrestrial carbon and nutrients (previously stored on land vegetation and soil) to the ocean. However, little is known about the potential effect of these terrestrial organic matter fluxes on the ocean biogeochemistry and uptake/release of carbon. To assess their effect on pCO2 variations during sea-level change, a transient deglaciation simulation using MPI-ESM and including such exchanges between land and ocean at transiently changing land-sea interface has been run. Results show that terrestrial organic matter inputs to the ocean, especially large during meltwater pulse periods, only have a local abrupt effect on ocean outgassing which is not enough to counterbalance the global CO2 uptake simulated during the deglaciation. Furthermore, the carbon to nutrients ratio and remineralization rates of terrestrial organic matter (wood, woody litter, humus) are poorly constrained parameters that can play a role on the local oceanic CO2 outgassing.

Date

04.05.2021

Time

15:15 h

Place

Virtual Seminar
Hamburg

Speaker

Thomas Extier, MPI-M

Organizers

Diego Jiménez-de-la-Cuesta Otero

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