As the climate continues to warm, permafrost thaw is increasing lateral fluxes of carbon (C) into aquatic systems. However, most studies characterize these fluxes from only one point in a catchment thus the spatial variability of lateral C fluxes from river networks in heterogenous landscapes is not well quantified. The transformation of this C as it flows throughout the catchment is also not well understood. To investigate how C quality and quantity vary across the terrestrial-aquatic interface, we sampled riparian porewater and surface water across a subcatchment that included different land-cover types. Our study subcatchment is 15 km2 and includes the permafrost peatland Stordalen Mire in Sweden (68°21′ N 18°49′ E). The catchment has four stream branches and the landscape transitions from alpine tundra at the upper elevations, then transitions to birch forest before draining into a discontinuous permafrost peatland. We sampled the catchment at high spatial frequency in July 2023 and determined the relative contribution of the varying landcovers to watershed C cycling. We characterized dissolved inorganic carbon, dissolved methane, dissolved organic carbon concentrations and composition (i.e., quality), ions, and nutrients along each stream branch across varying slopes within each land-cover type. To partition sources of carbon from landcover sources, we performed isotopic analyses (δ13C-CO2, δ13C-CH4) of dissolved gases. This spatially resolute sampling will allow us to identify lateral flux patterns across the terrestrial-aquatic interface within river networks and determine the relative contribution of different land-cover types to watershed-scale fluxes. Understanding how different land-cover types affect the spatial variability of C cycling across a watershed will be crucial for understanding watershed-scale lateral C flux as well as C transformation.
Authors
First Name
Last Name
Ruth
Varner
Cheristy
Jones
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Submission Details
Conference GRC
Event Graduate Research Conference
Department Natural Resources and Environmental Studies (GRC)