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.

Lieu
LOCEAN
Sorbonne Université, Campus Pierre et Marie Curie (Jussieu)
Couloir 45-55, 4^e étage, pièce 417

Visio
https://cnrs.zoom.us/j/95635246416?pwd=MWgyYlBXS3hWS01uSnpOMlFvcU02Zz09