Updated decadal and long term patterns of global Ocean oxygen change using Argo data

Montag 16.01.2023, 11:00 → 12:00 Europe/Berlin

Speaker: Dr. Nicolas Kolodziejczyk, University of Brest, CNRS, Ifremer, IRD, LOPS Laboratory, France

- online colloquium -

Where?    ZOOM: https://geomar-de.zoom.us/j/87698492885?pwd=Sm5lV3BpWlEzTElCeFU0Zzk1MHRwZz09
meetingID: 876 9849 2885
Code: 489055

 

Abstract:
Recent studies suggest a ocean global long term deoxygenation likely explained by anthropogenic warming. This tendency is also observed in the climate projection, however with  large uncertainties. Ocean deoxygenation is a major concern for marine life and human resources since it manifests notoriously by expansion of hypoxic zones and displacement of habitat for major pelagic species. Yet, lack of sustained and consistently sampled dissolved oxygen measurements put a large uncertainty on global and regional ocean oxygen change, and knowledge gap are still pending on physical and biogeochemical regional oxygen variability processes.
Since 2005 increasing Argo floats equipped with dissolved oxygen sensor have been deployed over the global ocean progressively populating regional basins over the last decades mainly in ocean ventilation zones of North Atlantic and Southern Ocean. This new Argo dissolved oxygen network, as part of the BGC Argo mission, provides us for the first time a regional and decadal insight over (quasi) global ocean within the first 2000 m depth.
Using ISAS optimal interpolation tools, we provide updated Argo oxygen global climatologies over the last decade. Over this period, highly variable regional patterns of oxygen change are revealed at interannual scale, contrasting with the general oxygen decline over the long term. For instance, during Argo period, Southern Ocean region appears to have loss oxygen, while North Atlantic subpolar region has gain oxygen. Insight in regional variability and associated physical and biogeochemical processes will be discussed.