Extreme weather events as proxies for climate change: carbon and metals in rivers and lakes of Siberia and European boreal zone

Tuesday, October 20 at 3 p.m.
Högbomsalen, level 3, Geovetenskapens hus

Oleg Pokrovsky
University of Toulouse

Catastrophic drought and flood events represent biogeochemical hot moments, when significant amount of solid, liquid or gases material exchange between soil, water and atmosphere. These events, although lasting from days to weeks, offer a unique chance to quantify the possible short-term consequences of on-going climate change according to various scenarios. In this regards, they allow assessing maximal possible impact of temperature rise and precipitation regime change on biogeochemical fluxes of dissolved and suspended forms of carbon and related elements.
Across a boreal zone in Northern Eurasia, from the largest European Arctic River, Severnaya Dvina, to western Siberia thermokarst lakes and the Ob’ River basin, I present the consequences of extreme water heating, phytoplankton bloom, lake evaporation and large river flood on concentration, speciation and fluxes of carbon, greenhouse gases and metals in rivers and lakes of the boreal and tundra zones, affected or not by the permafrost. It follows that the water heating lead to decrease of organic carbon and metal concentration in boreal lakes and the increase of CO2 and CH4 fluxes whereas the concentration and speciation of DOC and metals in rivers during extreme flood events remain quite stable.