Permafrost refers to ground that remains frozen continuously, consisting of soil, rock, ice, and organic material that stays at or below 0°C for at least two consecutive years, with some instances persisting for millions of years. This area contains a mix of organic matter, plants, and dead animals, preserved in ice since the end of the last ice age 11,000 years ago. As global temperatures increase, the active layer thickens, leading to a reduction in permanent permafrost. The active layer, a layer of earth above the permafrost, undergoes seasonal thawing and freezing. In colder regions, this layer is shallow, measuring only 10 to 15 centimeters, while in warmer permafrost areas, it can reach several meters in depth. During summer, vegetation covers this layer, and in winter, it is covered by snow. It serves as a thermal bridge between the permafrost and the atmosphere, moderating temperature changes at the permafrost's surface compared to ground level. Additionally, it facilitates the exchange of moisture and gases, providing essential water and nutrients for biological processes. Permafrost soils contain large amounts of organic carbon (C) and nitrogen (N), which can be released as dissolved organic carbon (DOC), dissolved organic nitrogen (DON), and dissolved inorganic nitrogen (DIN) during thawing periods. Although these releases affect the biogeochemistry of permafrost regions, there is a lack of comprehensive understanding regarding the chemical composition and source variability of DOC, DON, and DIN in active-layer and permafrost soils. DOC and total dissolved nitrogen (TDN), which includes DON and DIN, are crucial for terrestrial and aquatic ecosystem functions and greenhouse gas emissions. This occurs through biogeochemical cycling within soils, lateral transport to aquatic systems, and processing or export to coastal environments.

The breakdown of DOC in soils and surface waters generates CO2 and CH4, which are emitted into the atmosphere. DON and DIN serve as vital nutrients that enhance primary production and decomposition. Given the significance of DOC, DON, and DIN to ecosystem functions and gaseous and lateral fluxes, researchers conducted an evaluation of active layer soil and water quality in the surrounding area, with a particular focus on DOC, DIC, and DN. The evaluation of permafrost thawed active layer nutrients and nearby water bodies was conducted in the Leh district of Ladakh U.T, situated between 32°30´N to 35°00´N latitudes and 75°50´E to 79°10´E longitudes, with elevations ranging from 3500m to 5400 masl. (Figure 1). The majority of the study sites encompass the Ganglas catchment area. The higher elevations of the catchment contain a small cirque glacier named Pucche glacier, covering an area of 0.63km2. The findings highlight the complex interplay between permafrost thaw, nutrient release, and ecosystem functioning in cold-region environments. Seasonal and spatial variations in carbon and nutrient availability suggest that permafrost thaw not only alters local soil chemistry but also drives broader feedback to climate through greenhouse gas emissions. By influencing DOC, DON, and DIN fluxes, permafrost-active layer interactions contribute directly to atmospheric CO₂ and CH₄ concentrations and indirectly to aquatic productivity through nutrient delivery.