Ocean circulation is a key component of the present and past climate system. In particular, most previous studies have highlighted changes in surface and deep water masses, but few records provide information on intermediate water masses, despite their pivotal role in salt and heat transport on the timescale of glacial-interglacial cycles and abrupt events. We are therefore working to document the variability of intermediate water masses and the associated water, heat and salt fluxes in two key regions of the current climate system: i) the North Atlantic, and its connections with the Mediterranean Sea, in the context of current and future changes to the meridional ocean circulation system known as the ‘AMOC’, and the impact on the climate of northern Europe; ii) the northern Indian Ocean (Bay of Bengal and Arabian Sea), in relation to the Southern Ocean; and iii) the South China Sea. Our team is interested in reconstructing variations in circulation from the centennial scale to glacial-interglacial cycles, through the study of the mineralogical (clays, CaCO3 content, etc.) and geochemical (elemental ratios, isotopic geochemistry) of marine sediments and their biogenic fraction (corals, foraminifera). In order to better constrain these variations in the past, the records must be based on geochemical tools whose variations are well known; one of the key aspects of our research is the calibration of tracers, through the study of the relationship between environmental parameters and geochemical proxies under modern conditions (present-day seawater, living foraminifera, etc.).

Objectives of the Research Theme: Our research aims, on the one hand, to improve our understanding of the hydrology of the Mediterranean and the European margin in order to reconstruct the AMOC, and, on the other hand, to gain a better understanding of changes in ocean circulation in the Indian Ocean and the Southern Ocean.

List of permanent and non-permanent staff:

C. Colin, S. Sépulcre, S. Alphonse-Duchamp, G. Siani, A. Tudryn, Frédéric Haurine, J. Nouet, N.Pige, Gao Guohui, Yi Huang, Mingjun Li, Sun Tianqi