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).
The Mississippi River Basin Initiative is a federally funded project designed to reduce nutrient runoff in selected watersheds in the Midwest, including the Upper East Fork of the White River in Indiana. Our lab has partnered with the Upper East Fork Alliance to provide water quality monitoring for the 10 watersheds involved in the project. We are also exploring the use of stable isotopes (15N and 18O) in nitrate to determine changes in nitrate sources and the extent of denitrification. This work is funded by the Decatur County (IN) Soil and Water Conservation District.
Streams in urban and urbanizing watersheds receive inputs of pollutants from a variety of sources. Road salt and other deicers can enter through storm drains, as can many organic pollutants. Wastewater treatment plants also contribute pollutants, such as pharmaceutical compounds, which are not removed by traditional wastewater treatment. The ecological effects of these compounds in streams is largely unknown. We have been measuring the concentration of various urban pollutants in Jack's Defeat Creek, a local stream that is experiencing urbanization within its watershed. The goals is to determine how the concentration of these compounds changes in response to precipitation and stormwater run-off. Various aspects of this work have been funded funded by the Indiana Water Resources Research Center and the IU Faculty Research Support Program.