Permafrost landscapes are shaped by interactions among hydrology, geochemistry, and freeze–thaw dynamics. Thaw alters surface and subsurface flow pathways, mobilizing and transporting solutes (e.g., salts and contaminants) and reshaping aquatic chemistry. In turn, solutes can influence permafrost stability by depressing freezing temperatures and promoting further degradation. Cryopeg evolution, groundwater flow, thermokarst lake development, and surface water–groundwater interactions are known to regulate water and solute fluxes, but attention to such processes has been lacking across cryosphere and hydrology communities.

This session focuses on hydrological and biogeochemical processes in permafrost regions across scales. We invite contributions on water flow, solute transport, and chemical evolution in soils, surface waters, and groundwater of the terrestrial cryosphere. Topics may include cryopeg dynamics and salt migration, water body and thermokarst lake chemistry, isotope applications, coupled surface–subsurface pore water fluxes, and feedbacks between solute transport and permafrost thaw.

• B - Biogeosciences
• C - Cryosphere