In the framework of the Climate Graduate School, we are pleased to share the following seminar, dedicated to PhD students, Master students, Postdocs, and other researchers interested in oceanography, climate science, and marine ecosystems.

Date & Time: Friday, March 27, 2026, at 2 PM (Paris Time) Location: Grand Salle du LOCEAN, 4th floor, Corridor 45-55, Jussieu Invited Speaker: Mark D. Ohman Scripps Institution of Oceanography / University of California San Diego

Title: Climate Variability and Climate Change in an Eastern Boundary Current Upwelling Ecosystem

Abstract: Global Circulation Models (GCM) are increasingly used in both a diagnostic and prognostic manner to understand and forecast the consequences of anthropogenic climate forcing for marine biogeochemical cycles. However, such models better represent conditions of the open ocean than the coastal margins. Paradoxically, ocean margins – and especially the highly productive Eastern Boundary Current Coastal Upwelling Ecosystems – are disproportionately important to primary and secondary production, fisheries, the consequences of ocean acidification and hypoxia, and potentially to ocean Carbon storage. Ocean margins are also regions of elevated interaction with humans via Harmful Algal Blooms, marine mammal migrations, shipping, and pollutant transfer.

This presentation will highlight some of what has been learned from the California Current Ecosystem (CCE), perhaps the best-studied Eastern Boundary Current ecosystem. It will draw on results from CalCOFI, a multi-disciplinary ocean time series that is now in its 78th year, as well as a series of experimental process studies conducted by the NSF-supported California Current Ecosystem Long-Term Ecological Research site. The presentation will highlight intrinsic ecosystem variability of the CCE, known to occur on scales ranging from multiple decades (PDO, NPGO), to interannual (ENSO and other sources of Marine Heat Waves), to event-scale upwelling. Understanding these intrinsic sources of variability is essential to documenting the emergence of anthropogenic climate signals and their consequences. The presentation will also demonstrate how marine planktonic organisms can serve to amplify someperhaps of the effects of physical climate forcing. It will underscore the need for better representation of ocean margin processes, including planktonic food web dynamics, in ocean forecasts.

Contact: Francesco Dovidio, CNRS Researcher, LOCEAN-IPSL • francesco.dovidio@locean.ipsl.fr