Seasonal carbon dynamics of the Kolyma River tributaries, Siberia

• Main Authors: Keskitalo, Kirsi H., Bröder, Lisa, Tesi, Tommaso, Mann, Paul J., Jong, Dirk J., Bulte Garcia, Sergio, Davydova, Anna, Davydov, Sergei, Zimov, Nikita, Haghipour, Negar, Eglinton, Timothy I., Vonk, Jorien E.
• Format: Text
• Language: English
• Published: 2023
• Subjects: Arctic; Kolyma; kolyma river; permafrost; Siberia
• Online Access: https://doi.org/10.5194/egusphere-2023-1792; https://egusphere.copernicus.org/preprints/2023/egusphere-2023-1792/

Arctic warming is causing permafrost thaw and release of organic carbon (OC) to fluvial systems. Permafrost-derived OC can be transported downstream and degraded into greenhouse gases that may enhance climate warming. Susceptibility of OC to decomposition depends largely upon its source and composition which varies throughout the seasonally distinct hydrograph. Most studies to date have focused on larger Arctic rivers, yet little is known about carbon dynamics in lower order rivers/streams. Here, we characterize composition and sources of OC, focusing on less studied particulate OC (POC), in smaller waterways within the Kolyma River watershed. Additionally, we examine how watershed characteristics control carbon concentrations. In lower order systems, we find rapid initiation of primary production in response to warm weather, shown by decreasing δ 13 C-POC, in contrast to larger rivers. As Arctic warming and hydrologic changes may increase OC transfer from smaller waterways through river networks this may intensify inland water carbon outgassing.