Peatlands are a major source of dissolved organic carbon (DOC) for inland waters in Western Siberia. Continuous hydrological and hydrochemical monitoring of these peatlands is essential for understanding the global carbon cycle. We investigated a pristine ombrotrophic bog in Western Siberia to determine the links between seasonal hydrological changes and DOC quantity and quality. Specifically, we analysed water table fluctuations, DOC concentrations and spectral characteristics (SUVA 254 , E2:E3 and E4:E6 ratios). Our findings indicate that each peatland ecosystem exhibits distinct seasonal hydrochemical changes. The driest ecosystems (ryams) feature water with the highest DOC concentrations, characterised by high aromaticity and large molecular size, whereas the wettest ecosystems (pools) display the opposite trend. Surprisingly, the stream, which collects water from the entire peatland catchment, exhibits unique properties in that its DOC concentration is similar to that of wet ecosystems, while its spectral features more closely resemble those of dry ecosystems. Therefore, peatland ecosystems act as complex biogeochemical systems, modulating both the concentration and quality of dissolved organic carbon (DOC) based on prevailing environmental conditions.