Finescale currents, O(1-100 km, days-months), are actively involved in the transport and transformation of biogeochemical tracers in the ocean. In this seminar, I will discuss current knowledge of their overall impact on large-scale biogeochemical cycling on the time scale of years, which remain poorly understood due to the multi-scale nature of the problem. I will present the history of the study of these impacts, which have started roughly 30 years ago, when I arrived at LODYC (now LOCEAN). I will examine how eddy-fluxes and upscale connections enter the large-scale balance of biogeochemical tracers. I will show that the overall contribution of eddy-fluxes to primary production and carbon export may not be as large as for oxygen ventilation. I will highlight the importance of finescales to low-frequency natural variability through upscale connections. I will show that finescales may buffer the negative effects of climate change on the functioning of biogeochemical cycles.

These different points will be illustrated using recent (mostly > 2018) work conducted at LOCEAN-IPSL.

I will call for significant interdisciplinary efforts to properly account for the cross-scale effects of finescales on biogeochemical cycles in climate projections.

Date & Room: vendredi 20 octobre à 11h dans la salle du LOCEAN, couloir 45-55, 4ème étage, pièce 417. Ce séminaire sera en français.

Lien zoom: https://cnrs.zoom.us/j/96885952522?pwd=cWhDTHNXZmpBRlZzRVdnaDJUc2xWUT09