Nitrogen (N) removal via benthic denitrification in large river systems can be a significant sink of terrestrial N and a source of nitrous oxide (N2O) to the atmosphere. Recent studies have demonstrated the fraction of in-stream N removed from a river reach is related to the water residence time. We used the HYDRA aquatic transport model to examine the sensitivity of in-stream N removal and the associated N 2O emissions in the Mississippi River system to the interannual variability in climate. The results suggested an almost two-fold range in the percent of N removed in the Mississippi River system and a three-fold range in the associated N2O emissions, with the lowest percent removed (10-33%) and the highest N 2O emissions (15.5-26.0 106 kg N) occurring in the wettest years. The results demonstrate the importance of considering climate variability and change in the management of nutrient export by large rivers.
All Science Journal Classification (ASJC) codes
- Earth and Planetary Sciences(all)
- 1836 Hydrology: Hydrologic budget(1655)
- 1860 Hydrology: Runoff and streamflow
- 1871 Hydrology: Surface water quality
- 4805 Oceanography: Biological and Chemical: Biogeochemical cycles (1615)