Quantifying variability of soil organic carbon quality as a function of floodplain heterogeneity and downstream distance in a mountainous watershed
EMSL Project ID
49387
Abstract
Recent research has highlighted the importance of rivers and floodplains as a terrestrial carbon reservoir (Wohl et al., 2012; Regnier et al., 2013; Sutfin et al., 2016) and global assessments suggest that rivers could be a significant component of the terrestrial carbon budget (Cole et al., 2007; Battin et al., 2009; Tranvik et al., 2009; Aufdenkampe et al., 2011). Because poorly constrained terrestrial carbon fluxes contain the greatest amount of uncertainty among the primary reservoirs for global carbon (Friedlingstein et al., 2006) and floodplains may constitute a significant portion of terrestrial carbon sinks (Regnier et al., 2013; Sutfin et al., 2016), advancing understanding regarding carbon dynamics within floodplains will provide information necessary for improving global carbon budgets. Physical characterization and detailed mapping of geomorphic floodplain features, field samples of floodplain soils, analysis of soil organic carbon content, quantification of soil organic carbon (SOC), and characterization of CCC using NMR and high resolution mass spectrometry will be integrated to quantify carbon retention and potential implications for carbon storage and ecosystem processing. High-resolution satellite imagery (WorldView-2) and topographic data (airborne LiDAR) acquired in the summer of 2015 are being used to created detailed maps of geomorphic floodplain features (i.e., abandoned channels, oxbow lakes, and fluvial terraces) and differences in riparian vegetation communities (meadows dominated by grasses and sedges, clusters of willow, and tree stands) where distinct features are not present. The proposed study will be the most detailed mapping of floodplain SOC to date. This work will be conducted on a 12-km long segment of the East River ~2 km upstream of Crested Butte, Colorado and within the Rocky Mountain Biologic Laboratory. Nuclear magnetic resonance and high resolution mass spectrometry of clay-sized and light fractions will be used to investigate the quality of soil organic carbon within a riparian ecosystems along the East River, CO to test the hypothesis that the variance in soil organic CCC is significantly different between distinct geomorphic feature and riparian vegetation communities. We posit that variations in grain size fractions and the composition of soil organic carbon are controlled by both discernable gradients and strong local heterogeneity in CCC in floodplains. The proposed research will fulfill the primary goals of the Terrestrial and Subsurface Ecosystems (TSE) theme at EMSL by determining the chemical form of organic matter in soil, providing insight into the mechanistic understanding of the terrestrial carbon cycle, and informing biogeochemical components of the carbon cycle within freshwater systems.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2016-10-01
End Date
2017-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members