Environmental drivers of denitrification rates and denitrifying gene abundances in channels and riparian areas

摘要: Intensive agriculture in the Midwestern United States contributes to excess nitrogen surface water and groundwater, negatively affecting human health aquatic ecosystems. Complete denitrification removes reactive from environments releases inert dinitrogen gas. We examined rates abundances of denitrifying genes total bacteria at three sites an agricultural watershed experimental stream Minnesota. Sampling was conducted along transects with a gradient always inundated (in-channel), periodically inundated, non-inundated conditions determine how gene varied channels riparian areas different inundation histories. Results indicate coupling between environmental parameters, abundances, in-channel locations, limited no respectively. Nutrient-amended potential for locations were significantly correlated (α = 0.05) five six measured whereas each only abundance one gene. These results suggest that DNA-based analysis alone cannot predict functional responses (denitrification potential), especially studies varying hydrologic regimes. A scaling performed develop predictive relationship relating parameters locations. This method could be applied other geographic climatic regions occurrence hot spots.