Environment, Paleo-Environment, and Bio-Indicators

Research on the Environment, Paleo-Environment, and Bio-Indicators of the laboratory UMR 6112 includes a wide range of projects on the functioning of Modern Marine Ecosystems, Paleoceanography, and processes on a Land-to-Sea Continuum.

Modern Marine Ecosystems

Our projects focus on modern benthic and planktic marine ecosystems, and a better understanding of the formation of fossil assemblages. Analyses of planktic foraminifer production, ecology, and particle fluxes in the water column are targeted towards quantification of the transfer of carbon (e.g., CO2 budget) from the surface to the deep ocean (biological carbon pump). Ecological studies of benthic foraminifer assemblages focus on high-productivity and low-oxygen conditions as, for example, upwelling areas, submarine canyons, eutrophic shelf seas. In those areas we analyse and quantify 1) the flux of organic matter to the sea floor, 2) bottom water oxygenation, 3) redox conditions in surface sediments, and the 4) temporal variability of sea floor environments. Sub- and anoxic ecosystems are analyzed using in-situ and laboratory experiments, with the aim to obtain a more complete understanding of the role of foraminifers in biogeochemical cycles, in particular the nitrate cycle.

Paleoceanography

Our projects in paleoceanography focus on both the development and calibration of novel proxies, and their application in reconstructing the late Quaternary paleoenvironment. We conduct multiproxy studies combining biological, biogeochemical, and sedimentological analyses. Our projects particularly focus on quantitative paleoceanographic reconstructions by analyzing biogenic carbonates including benthic and planktic foraminifer, deep water corals, and marine bivalves. Our approach to develop new proxies is highly original, and combines 1) culturing experiments (foraminifers), 2) automated image analysis, and 3) LA-ICP-MS analyses of element ratios (metal/Ca ratios) of biogenic carbonates. Our integrated approaches are targeted to improve the calibration of paleoceanographic proxies (e.g., temperature, salinity, productivity, oxygen, and carbonate budgets).

Land-to-Sea Continuum

Our work on exchange processes on the land-to-sea continuum focuses at improving the understanding of catchment areas and estuaries, including transfer of chemical and particulate matter from the continent to the ocean. We conduct multidisciplinary projects in a wide variety of environments from urban areas, agricultural and mining areas, to coastal and fully marine environments. Our research aims at measuring and understanding the mechanisms, which control the transfer of chemical elements and nutrients (e.g., C, N, P, Fe), as well as metal contaminants (e.g., Cu, Pb). We aim to better understand the interactions between soils and plants, cities and rivers, rivers and oceans, as well as the relationships between bacteria and plants, microphytobenthos and meiofauna. Pollution management of soils and sediments is approached through bioremediation / phytoremediation. New methodologies of remote sensing (LIDAR) and seismics focus on sediment dynamics in rivers and along the coast to assess risks like submersion and inundation. Impacts of human activity on marine and coastal systems as eutrophication, ocean acidification, and pollution (e.g., sewage outlets, and offshore oil rigs) are studied by means of bioindicator species.



Details of themes : Open Marine Benthic ecosystems - Foraminiferal metabolism and its role in geochemical processes - Planktic foraminifera ecology in marginal basins - Foraminifers as proxy of the marine carbon cycle and ocean acidification - Paleoceanographical Proxies - Holocene climate variability _ a marine perspective - Pleistocene climate variability _ marine perspective - Zone critique: sols pollués et remédiation - Trait de côte et aléa submersion marines - Minéraux environnementaux: remédiation et dissémination - Estuaries, deltas and underground estuaries: Continent-ocean transfer - Anthropogenic impact on mudflats, Iagoons and mangroves - Hypoxia and anoxia on continental shelves - Environmental biomonitoring using benthic foraminiferal faunas - Télédétection hyperspectrale du microphytobenthos - Plants and their interactions with microorganisms in early terrestrial environments