Continental inputs to the ocean provide most of the nutrients required for photosynthesis, and thus modulate the export of particulate carbon to the deep ocean (also known as the biological carbon pump). Under the impact of climate change, these continental inputs are set to evolve and modify marine chemistry and biological activity. This is particularly true in Arctic areas, where coastal erosion is accelerating and where the gradual retreat of the pack ice allows better light penetration, stimulating photosynthesis. Mélanie Grenier will be presenting her work on the study of the variability of particle flux and circulation in the Amerindian Basin of the Arctic Ocean between the 1990s and 2010s, through the analysis and modelling of the tracer 230Th, in the context of Arctic amplification. She will also present the characterisation of the neodymium isotopic composition of river water in the Canadian Arctic Archipelago, which she has carried out to trace and quantify continental river inputs to this region. She will conclude with a presentation of the research project to which her studies have led her, which she is proposing through a CNRS CR application in Toulouse (LEGOS). Her project concerns the study of continental inputs to the Arctic Ocean, in terms of flows, sources and oceanic transport. Mélanie proposes the joint analysis of different geochemical tracers - the isotopes 230 and 232 of thorium, and the isotopes 7, 9 and 10 of beryllium - whose properties make it possible to distinguish different sources of input and to quantify the flows. The characterisation of the fate of these inputs in the ocean is based on the combination of these geochemical analyses with Lagrangian analyses of the modelled circulation. The aim of his project is to quantify the contribution - as yet poorly known - of continental input vectors to the ocean that are likely to change under the impact of climate change: melting permafrost and pack ice.