Data associated with Geomorphic controls on floodplain soil organic carbon in the Yukon Flats, interior Alaska, from reach to river basin scales

• Main Authors: Lininger, K. B., Wohl, E., Rose, J. R.
• Format: Dataset
• Language: English
• Published: Colorado State University. Libraries 2018
• Subjects: organic carbon; Yukon River; Alaska; geomorphic units; floodplain; fluvial geomorphology; Dall River; Yukon; Yukon river
• Online Access: https://hdl.handle.net/10217/185889; https://doi.org/10.25675/10217/185889

The dataset describes floodplain soil samples taken from the Yukon Flats region in interior Alaska, which were analyzed for organic carbon concentration, soil texture, and soil moisture. Statistical models were used to assess the geomorphic controls on floodplain soil organic carbon. These data were collected in the Yukon Flats Region during Summer 2014 and Summer 2015. Floodplains accumulate and store organic carbon (OC) and release OC to rivers, but studies of floodplain soil OC come from small rivers or small spatial extents on larger rivers in temperate latitudes. Warming climate is causing substantial change in geomorphic process and OC fluxes in high latitude rivers. We investigate geomorphic controls on floodplain soil OC concentrations in active-layer mineral sediment in the Yukon Flats, interior Alaska. We characterize OC along the Yukon River and four tributaries in relation to geomorphic controls at the river basin, segment, and reach scales. Average OC concentration within floodplain soil is 2.8% (median = 2.2%). Statistical analyses indicate that OC varies among river basins, among planform types along a river depending on the geomorphic unit, and among geomorphic units. OC decreases with sample depth, suggesting that most OC accumulates via autochthonous inputs from floodplain vegetation. Floodplain and river characteristics, such as grain size, soil moisture, planform, migration rate, and riverine DOC concentrations, likely influence differences among rivers. Grain size, soil moisture, and age of surface likely influence differences among geomorphic units. Mean OC concentrations vary more among geomorphic units (wetlands = 5.1% vs. bars = 2.0%) than among study rivers (Dall River = 3.8% vs. Teedrinjik River = 2.3%), suggesting that reach-scale geomorphic processes more strongly control the spatial distribution of OC than basin-scale processes. Investigating differences at the basin and reach scale is necessary to accurately assess the amount and distribution of floodplain soil OC, as well as the geomorphic controls on OC. National Science Foundation (NSF) DGE-1321845. National Geographic Society 9449-14.