Dynamics of Carbon Pools in High Arctic Permafrost

A major concern about present warming trends in Arctic areas is a potential for positive feedbacks due to release of CO2 and CH4 from breakdown of soil organic carbon (SOC). Recent results suggest that SOC values in the High Arctic have been underestimate d, due to a small number of studies, shallow sampling, and poor characterization of SOC distribution across patterned ground. Accelerated warming in arctic regions may deepen the active layer, thaw permafrost, and decompose formerly sequestered SOC. The H igh Arctic geomorphic system may, however, also respond to warming by increasing soil turnover and SOC burial, thus providing negative feedbacks currently not appreciated. The present pilot project aim at providing estimates of SOC content and past and p resent organic carbon sequestration rates of soils in the Svalbard High Arctic. The project is facilitated by an opportunity for coupling past and present monitoring of soil dynamics in sorted circles on Kvadehuksletta near Ny-Ålesund, Svalbard, across a period where global warming may already have caused ground thermal impact in the High Arctic. Present surface dynamics of sorted circles will be determined by multi-temporal digital photogrammetry. SOC content and age wil be investigated by trenching si tes, mapping horizons, soil sampling and 14C dating. Initial SOC data from solifluction (coring/trenching) and rock glaciers (surface and frontal slope sampling) will also be collected. By combining knowledge about sorted circle surface dynamics with inv estigations of SOC distribution and age at different depths, we intend to interpret relationships between SOC sequestration and palaeoenvironment. From this, we expect to develop the basis for a more general conceptual model for the carbon pool dynamics o f cryoturbated soils as a function of ground thermal conditions. The data from solifluction and rock glaciers will probably be the first attempt to investigate their role in High Arctic carbon pool dynamics.