Water Resources Research Act Program

Details for Project ID 2006IN190B

Trace Gas Fluxes in Riparian Buffers along an Urban Rural Gradient

Institute: Indiana
Year Established: 2006 Start Date: 2006-03-01 End Date: 2007-02-28
Total Federal Funds: $20,000 Total Non-Federal Funds: $58,415

Principal Investigators: Pierre-Andre Jacinthe

Abstract: ABSTRACT

Riparian ecosystems act as natural filters for various water pollutants, thereby contributing to reduction in nutrient loadings to adjacent water bodies. While the contribution of riparian buffers to water quality maintenance is well documented, much less is known regarding the linkage between microbial transformation of nutrients in riparian zones and production of the trace gases carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). This information is important given the implication of these gases in climate warming and atmospheric chemistry. Trace gas emission needs to be quantified to assess the overall environmental benefits of riparian buffers, and more specifically, to determine whether water quality improvement in riparian buffers is imply a pollution swap, and is achieved at the expense of air quality. In the proposed study, trace gas fluxes will be monitored in an urban to rural transect of riparian buffers along the White River in central Indiana. Gas flux measurements made at the urban end of the transect during the period August-November 2005 have shown that CO2 and N2O emission in areas near (10 - 15 m) the river were 1.5 times greater than at sampling points 30 m from the river margin. Results have also shown that the riparian soils acted as a net sink for CH4 (mean SE: -0.42 0.03 mg CH4 m-2 d-1, n =96 observations) regardless of location relative to the river. The finding that these riparian soils are able to consume CH4 is somewhat intriguing, and deserves further studies. Monitoring will continue over several more seasons in order to assess the impact of flooding events and water table fluctuation on trace gas fluxes. A rural riparian site will also be included to assess the effect of urbanization on the dynamics of trace gases in riparian soils. Results of this study further our understanding of the biogeochemistry of riparian soils.