The silicon cycle is a historical LEMAR theme.


The study of the trace metals cycle is one of LEMAR’s strong themes. Improving our knowledge of the metal cycle is crucial to better understand and quantify oceanic biogeochemical cycles of major elements (C, Si, N, S) and the biological carbon pump. The analysis of trace metals and their speciation is particularly difficult because their concentrations are extremely low and their cycle is complex. LEMAR is one of the internationally recognized laboratories for the study of the trace metals cycle, notably through the use and development of advanced techniques (SF-ICP-MS in the context of PSO, FIA, voltammetry). Our expertise in both the dissolved and particulate phase will allow us to study the interactions between these two reservoirs, notably at the oceanic interfaces. These interactions are very little studied at present and yet fundamental to better understand the bioavailability of metals. This theme will strengthen our international visibility, particularly in the context of new GEOTRACES oceanographic campaigns.

The study of the land-sea continuum

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The coastal zone, at the interface between the earth system and the sea system, concentrates a set of interfaces and natural environmental gradients, generating a very strong heterogeneity at different spatio-temporal scales. Scientific questions are therefore numerous to try to better understand the nature and dynamics of physical, biological and geochemical flows and forcings, and their interactions and feedbacks (prospective SIC-INSU). Extremely dynamic and complex, this coastal zone is also the seat of many facets of global change with climate change of course, but also strong and growing anthropogenic pressures related to urban planning, land use, exploitation mineral and living resources on land and at sea. In this context, our objectives are threefold:

● develop an integrated approach to land-to-sea transfers of dissolved and particulate matter, combining observation, process studies and modeling in estuaries and coastal areas to better understand the coastal ecosystem’s response to physical, biogeochemical forcings and biological, terrestrial and oceanic (Axis 1 of Team 3);

● Anticipate the possible evolution of the coastal ecosystem in response to global change, by developing scenarios describing the response of organisms and the coastal ecosystem to the interaction of different facets of global change: climate change, change in farming practices evolution (natural or not) of invasive species (Axis 1 of team 3, strong links to develop with the AR5 of team 2), and

● to develop a transdisciplinary approach allowing the co-construction of these scenarios and their analysis with the concerned actors, with a view to decision support in the sustainable management of the coastal socio-ecosystem (links with the “Rade de Brest” axis And with the “unruly” axis, links with the other components of the IUEM).


Marie Vagner