Water Resources Research Act Program

Details for Project ID 2008PA87B

Controls on nitrogen and phosphorous transport and fate in northern Appalachian streams

Institute: Pennsylvania
Year Established: 2008 Start Date: 2008-03-01 End Date: 2009-02-28
Total Federal Funds: $20,000 Total Non-Federal Funds: $40,690

Principal Investigators: Mike Gooseff

Abstract: The transport of elevated concentrations of nutrients, particularly nitrate (NO3), in streams can greatly impair receiving water bodies, leading to eutrophication. In Pennsylvania, this is exemplified in the nutrient contributions of the Susquehanna River, and its watershed, to Chesapeake Bay. Small streams have been the focus of much recent work in aquatic nutrient uptake dynamics, because there are so many of them (compared to the number of larger streams), and because there is likely to be good contact between flowing waters and streambed substrate, which hosts the biota that are generally responsible for nutrient uptake in small streams. There has been, however, little, if any, research into potential uptake dependencies between nitrate and phosphorous during nutrient addition experiments. Here we attempt to discern whether such a dependency exists in two study stream reaches one forested (low NO3 concentrations) and one agricultural (high NO3 concentrations) over a range of discharges and stream background concentrations. We propose to perform repeated stream tracer experiments and nutrient (nitrate, phosphate, and both together) enrichment experiments and then simulate conservative and non-conservative transport of the injected solutes as well and determine nutrient uptake demand. This set of experiments will allow us to determine 1) whether nitrate uptake is enhanced by elevated concentrations of phosphate 2) to what extent this interaction changes throughout a typical summer growing season (given changes in stream biota and discharge), and 3) how this dynamic may vary between low and high background NO3 concentrations. This array of nutrient uptake contexts will allow us to consider the potential end members of NO3 conditions in Pennsylvania streams. These findings will be valuable to watershed managers and state planning agencies who may currently be making decisions about management strategies that are not necessarily linked to potential stoichiometry of nutrient uptake in streams, or temporal dynamics of uptake change throughout seasons.