Headwaters streams can be important areas of stream nitrogen retention. My research in this area has focused on evaluating the influence of stream wood on the uptake and retention of nitrogen (as nitrate) in forested headwaters streams. Wood in streams is has been shown to increase the retention of both organic matter and fine inorganic sediments, which should both directly and indirectly increase in nitrogen uptake and retention. In a manipulative experiment, however, we found that wood removal enhanced summer nitrate uptake (Warren et al. 2013). Although this is contrary to our initial hypothesis, it has raised new questions about how wood alters stream substrates and how that in turn influences the potential abundance of stream periphyton (by retaining stream sediment, wood can reduce the amount of exposed stable substrates on which periphyton can grow. I am continuing to conduct research on the question of substrate influences on stream nutrient demand and how substrates and wood interact in this context.
Collaborators
- Dr. Darren Bade
- Dr. Kristin Judd
- Dr. Gene Likens
- Dr. Clifford Kraft
- Dr. Heather Bechtold
- Dr. Emma Rosi-Marshall
- Dr. Gordon Grant