Seasonality of DOC Export From a Russian Subarctic Catchment Underlain by Discontinuous Permafrost, Highlighted by High‐Frequency Monitoring

Intense climate change and permafrost degradation impact northern watersheds ultimately organic carbon transfer from terrestrial to aquatic ecosystems. We investigated the contemporary dissolved (DOC) dynamics in a catchment underlain by discontinuous (Graviyka River, Siberia), where historical meteorological hydrological data are available since 1936. Mean annual air temperature (MAAT), contrast precipitation discharge was found show significant increasing trend 1950. Using situ sensing of fluorescent matter (fDOM), we estimated DOC concentrations at high temporal frequency (1h) during 3 years (2015ŌĆō2018), calculated specific fluxes 5.2ŌĆō5.5 g C m2 yrŌłÆ1. High (above 10 mg LŌłÆ1) sustained all year, exhibiting nearly chemostatic behavior. Nevertheless, high-frequency survey other water parameters revealed seasonality origin pathways watershed. The spring freshet dominates export (up 80%), but summer autumn floods can also contribute up 9% 8% respectively. sampling able capture dynamic concentration flood (DOC peak preceding discharge, dilution freshet) (contribution DOC-rich, low conductivity water). These observations suggest contribution organic-rich originating peatlands, potentially degrading palsas. study demonstrates both that is essential key events for export, more long-term monitoring urgently needed these rapidly evolving watersheds.