Comparison of hydrochemistry and organic compound transport in two non-glaciated high Arctic catchments with a permafrost regime (Bellsund Fjord, Spitsbergen).

An increase in air temperature related to climate change results in the retreat of glaciers, the degradation of permafrost, and the expansion of glacier-free areas in the polar regions. All these processes lead to changes in the Arctic landscape. They influence the hydrochemistry of streams and rivers fed by glaciers and thawing permafrost. In this study, we examine eighty two water samples from two non-glaciated catchments with snow-permafrost regime: the Tyvjobekken Creek and the Reindeer Creek (NW Wedel-Jarlsberg Land, Spitsbergen). We cover hydrometeorological measurements, fluctuations of physicochemical parameters (pH, specific electrolytic conductivity (SEC)), and the presence of selected organic compounds (dissolved organic carbon (DOC), formaldehyde (HCHO), ∑phenols). The obtained levels of DOC (0.061-0.569mgCL-1) and HCHO (<LOD-0.140mgL-1) in water samples of these two high Arctic creeks confirm the role of the melting permafrost as a rich source of terrestrial organic carbon and organic pollutants, as well as the impact of rainfall on surface water chemistry. It was found that fluctuations of physicochemical indices (pH, SEC, DOC) were related to changes in mean daily discharge of Reindeer Creek (0.012-0.034m3s-1) and Tyvjobekken Creek (0.011-0.015m3s-1) (r>0.40). The Tyvjobekken Creek catchment, in contrast to Reindeer Creek catchment, turned out to be resistant to rapid changes in meteorological conditions (r<0.10) and surface runoff. The processes of permafrost thawing, calcium carbonate dissolution, and biogeochemical "breathing" of soils proved to be crucial for the development of water chemistry. In conclusion, the surface water chemistry of the Reindeer Creek was found to result from the mutual influence of hydrometeorological indices and the biogeochemical environment of the catchment.