Dialynas et al., 2015

Talk/Poster

Topographic variability in the influence of soil erosion on the carbon cycle

Dialynas, Y. G., Bastola, S., Bras, R. L., Billings, S. A., Richter, D. deB., and Markewitz, D. (2015)
Calhoun CZO 2015 Summer Science Meeting  

Abstract

Soil erosion, particularly that caused by agriculture, is closely linked to the global carbon (C) cycle. There is a wide range of contrasting global estimates of soil-atmosphere C exchange partly due to limited understanding of how geomorphology, topography, and land management practices affect erosion and transport of soil organic C (SOC). Here we present a physically-based approach that stresses the fine dynamics and spatial heterogeneity of SOC erosion and atmospheric C sequestration. The methodology was implemented in tRIBS-ECO (Triangulated Irregular Network-based Real-time Integrated Basin Simulator-Erosion and Carbon Oxidation), a spatially-explicit model of SOC dynamics built within an existing coupled physically-based hydro-geomorphic model. We study a region recovering from some of the most serious agricultural erosion in North America. We utilize measurements of biogeochemical characteristics at multiple depths. We found that topographically induced variations of C erosion and replacement can be markedly higher than the variability among reported point estimates globally. We estimated that the net atmospheric C exchange ranges from a maximum source to a sink of 14.5 g m-2 yr-1 and 18.2 g m-2 yr-1, respectively. Applying results globally yields a maximum source and sink of 0.73 Pg yr-1 and 0.91 Pg yr-1, respectively. We conclude that the small scale complexity of C erosion and burial driven by topography exerts a strong control on the landscape's capacity to serve as a C sink or a source. We suggest that the significant spatial variability of C fluxes should be explicitly accounted for in regional and global C budgets.

Citation

Dialynas, Y. G., Bastola, S., Bras, R. L., Billings, S. A., Richter, D. deB., and Markewitz, D. (2015): Topographic variability in the influence of soil erosion on the carbon cycle. Calhoun CZO 2015 Summer Science Meeting.

This Paper/Book acknowledges NSF CZO grant support.