In order to characterise the impact of climate change over marine ecosystems, physico-biogeochemico-biological coupled models need to be improved on different scales, from sub-meso to basin scales.

Modelling this coupling is a real challenge around which teams from Research Axis 2 join forces. A new approach lies on a) studying key processes that control physical and biological response of continental margins and b) developing proxies to analyse past climate variability in marine environment from bio structures such as shells (from which daily temperature variations may be obtained for instance).

Research Axis 2 also stands out in France by stepping over the separation between coastal and blue water oceanographic research (this separation is often made amongst oceanographers) and by bringing together expert researchers in physics, biogeochemistry, biology) into multidisciplinary projects.

The operational aims of the project are to create synergy and to reinforce regional expertise on physical variations of the ocean in relation to climate change, and on interactions between various spatial-temporal scales of these variations and their consequences over marine ecosystems. This translates into the following key questions:

Variability of heat and salt content of the ocean

(and in particular the strong thermohaline anomalies of the subpolar and subtropical gyres of the North Atlantic, in relation to climate variations);

Variability of thermohaline circulation of the North Atlantic

(studied via a long term data acquisition program of the meridional thermohaline circulation cell) ;

Sensibility of biogeochemical cycles to the North Atlantic variability;

Role of the ocean in marine ecosystems evolution and in carbon flux regulation;

Comparative and integrative dynamical study of coastal upwelling systems caused by winds, density gradients and tides

(4 major East coast upwelling systems, as well as transient and seasonal upwelling systems), including balancing and instability phases, and links with fluxes and biological (in particular quantifying horizontal and vertical onshore-offshore exchanges) and their impact on chemical elements and biological species distribution.
This project will build upon international programs such as CLIVAR (climate variability) and IMBER (impact of global change on marine Ecosystems), and upon European networks such as EUROCEANS (joint study of the Atlantic Ocean and Arctic seas), BASIN (climate variability impact on pelagic ecosystems of the North Atlantic and its continental margins) and MERSEA (forecast modelling of the ocean state and its evolution). Experts from Research Axis 2 are involved in current international programs (WOCE OVIDE, GOODHOPE) that have already revealed the detailed structure of ocean masses and their circulation in the North Atlantic.

Mutualisation of data acquisition campaigns in the field, sharing of synergetic tools (inverse models, Lagrangian models), and joint interpretation by specialists from various disciplines of field data and high resolution satellite data (SST, SSS, altimetry) are real life examples of the multidisciplinary expertise of the teams that drive Research Axis 2.