Stable Water Isotope Assessment of Tundra Wetland Hydrology as a Potential Source of Arctic Riverine Dissolved Organic Carbon in the Indigirka River Lowland, Northeastern Siberia

Arctic tundra wetlands may be an important source of dissolved organic carbon (DOC) in rivers and the Ocean under global warming. We investigated stable water isotopes DOC concentration wetlands, tributaries, mainstream at lower reaches Indigirka River northeastern Siberia during summers 2010–2014 to assess complex hydrology role as sources riverine DOC. The had higher values δ 18 O than tributaries River. A relationship between two parameters was observed mainstream, suggesting can a for through tributaries. combined temporal variations indicate flowed into relatively high river-level periods summer, whereas downstream could discharged low periods. minor fraction (7–13%) wetland degraded 40 days dark incubation. Overall, potentially provide less biodegradable river costal ecosystem periods—from late summer autumn.