I am a geochemist, doing both magmatic and aquatic (marine, groundwater) chemistry. Current main interests are aspects of submarine hydrology (interaction between the ocean and seafloor or aquifers) and fluxes of particulate and dissolved matter in the oceanic system and between land and the sea, with implications to major biogeochemical cycles, such as the C and N cycles. I have a lab of radioactive isotopes, mainly of the U-Th system, which allows tracing fluxes in the sea and in other environmental reservoirs. We also use radioactive isotopes to address other important environmental issues, such as the current thawing of frozen lands in the Circum-Arctic due to climate change.