Land-ocean-climate interactions in high northern latitudes

点击翻译按钮获取中文摘要

The research program deals with late Cenozoic to recent climate changes at high latitudes of the Northern Hemisphere, as recorded in geological archives. It addresses three complementary questions about land-ocean-climate interactions. One concerns the large-scale exchanges between the subarctic Pacific, Arctic and North Atlantic oceans that exert an important role on the freshwater budget, thus salinity, water mass stratification, sea ice, and heat redistribution through ocean circulation. The second focuses on epicontinental environments, at the transition between land and ocean, where terrestrial freshwater discharge impacts hydrographic conditions. The third deals with seasonality, which is a critical component of climate that also depends upon salinity and stratification of water masses in marine environments. ***The long-term objective is the understanding and assessment of the role of freshwater in the climate system at high latitudes, from hemispheric to regional scales, while short-term objectives are defined with more specific temporal and spatial foci. At hemispheric scale, they include (1) the reconstruction of marine environments in the western Arctic (Chukchi, Bering seas) where freshwater and nutrient inputs from the North Pacific are determinant on sea ice and productivity, (2) the elucidation of the relationships between the modes of Arctic sea ice variability vs the exchanges with the subarctic Atlantic and Pacific seas, and (3) the evaluation of the relative impacts of Arctic Ocean outflows through Fram Strait vs the Canadian Arctic Archipelago, on the northern North Atlantic oceanography. At the regional scale of epicontinental settings, they include (4) the documenting of interactions between ocean and continental ice stability or melting along the Greenland margins, and (5) the reconstruction of climate and hydrography variabilities along the northern and eastern margins of Canada, in particular the coasts of Yukon, Hudson Bay, Labrador shelf and the Gulf of St. Lawrence. ***The research program mostly relies on access to marine sediment cores collected within the framework of international collaborations. It is built from methodologies developed over the last decades, but still in progress. They combine micropaleontological, geochemical and isotopic proxies to simultaneously reconstruct complementary parameters of climate, sea surface and deep marine conditions. ***The projects conducted as part of the research program involve participation of graduate students and are coordinated within the framework of international initiatives combining proxy paleoclimate and paleoecological data acquisition/compilation with climate modelling efforts. Beyond the development of fundamental knowledge about land-ocean-climate interactions at millennial to on-going "global changes" scales, the outcomes of the research program also include the development of tools for environmental issue assessments.*****