Denitrification is a critical, natural process carried out by various groups of bacteria. Quantifying the factors which control denitrification rates and explaining spatial and temporal patterns in denitrification rates have long been a challenge. The goal of this study is to determine the extent to which patterns in denitrification can be explained by the genetic structure of bacterial communities and the interactions between bacteria and other environmental factors, such as the chemistry of dissolved organic matter. The project is located in an agricultural landscape in central Indiana. The study combines modern molecular biology with recent advances in use of isotopic tracers to measure in-stream denitrification rates. This 4-year project is funded by the National Science Foundation (DEB-0743396).
Organic wastewater contaminants, such as pharmaceutical compounds, often are not removed by traditional wastewater treatment. They can be detected in most streams and rivers, particularly if the stream receives sewage effluent. The ecological effects of these compounds in streams is largely unknown. In this project we are measuring the concentration of these compounds in a stream network that drains a rapidly urbanizing watershed in south-central Indiana. The goals is to determine how the concentration of these compounds changes in response to precipitation and stormwater run-off and to quantify the contribution from point vs. non-point sources throughout the stream network. This project is funded by the IU Faculty Research Support Program.