Arctic rivers, despite the relatively small area they occupy, play an important role in regulating the Arctic’s carbon budget. Permafrost underlies one quarter of the Northern Hemisphere’s land area and stores approximately 1700 Petagrams (1 Pg = 1015 g) of organic carbon (OC), accounting for roughly half of the terrestrial soil carbon stock (Tarnocai et al., 2009; Miner et al., 2022). Thawing of permafrost soils in the Arctic could serve as a positive feedback on global temperatures if massive amounts of OC are released from this previously frozen reservoir (DeConto et al., 2012; Schuur et al., 2015). Rivers are some of the most dynamic features of the arctic landscape, yet their geomorphic roles and place in the global carbon cycle are poorly understood. The North Slope of Alaska is a vast region with great variation in geomorphic surface types, ranging from expansive peat-rich sedgelands to abandoned river meander bends to fluvial sand and gravel bars. Quantifying the stock and residence time of OC on these surfaces will help determine the rates of carbon burial and decay in Arctic river floodplains. Using Optically Stimulated Luminescence (OSL), radiocarbon (14C) dating, bulk density measurements, and Loss on Ignition (LOI) of soil samples from the Canning River floodplain, I will determine the carbon stocks and residence times of different geomorphic surfaces. Geomorphic surfaces in the Canning River floodplain will be identified and mapped based on characteristics like elevation, landforms, normalized difference vegetation index (NDVI), water saturation, sediment grain size, and organic carbon content. These surfaces will be differentiated in satellite imagery and the collected data will be mapped to their respective areas. Remote sensing of the river corridor will allow field and laboratory measurements to be scaled up to make comprehensive estimates of carbon stocks and flux in the Canning River floodplain, with implications for river floodplains across the greater Arctic region.
Graduate Student Geosciences, CU Boulder