Quantifying the influence of groundwater discharge induced by permafrost degradation on lake water budget in Qinghai-Tibet Plateau: using 222Rn and stable isotopes

A latest thermokarst lake sampling program was carried out in the Source Area of the Yellow River in September, 2019. Isotopic signatures in water including delta O-18, delta H-2 and Rn-222 activities in thermokarst lakes and groundwater were systematically reported. Furthermore, lake water balance metrics and groundwater contributions to lakes were quantified via two isotope mass balance models. Results showed the robust but complex hydrological responses driven by progressive permafrost thaw. Further quantifying the relations between water volumes and other observed biogeochemical impacts to understand the mechanisms in geochemical feedbacks driven by permafrost degradation was needed.