Nitrogen and carbon flow from rock to water: Regulation through soil biogeochemical processes, Mokelumne River watershed, California, and Grand Valley, Colorado

Soil denitrification is an ecologically important nitrogen removal mechanism that releases to the atmosphere the greenhouse gas N2O, an intermediate product from the reduction of NO3 − to N2. In this study we evaluate the relationship between soil carbon and denitrification potential in watersheds with bedrock acting as a nonpoint source of nitrogen, testing the hypothesis that nitrate leaching to stream water is in part regulated by denitrification. Two sites, one in a Mediterranean climate and the other in an arid climate, were investigated to understand the interplay between carbon and denitrification potential. Both sites included carbonaceous bedrock with relatively high nitrogen concentrations (>1,000 mg N kg−1) and had low background [...]