His research investigates patterns and processes in freshwater ecosystems, combining physical, chemical and biological measurements to understand the connections between the components of these dynamic ecosystems. His current projects seek to elucidate the controls on water quality parameters, such as suspended sediment and dissolved nutrients, in Iowa streams, rivers, and wetlands. In his previous research, he has assessed restored urban streams in Milwaukee, Wisc., studied the linkage between microbial diversity and nutrient uptake in macrophyte-rich streams in Denmark, and investigated the effect of annual salmon migrations and watershed timber harvest on streams in Southeast Alaska.