Influence of Woody Debris on Stream Nitrogen Retention
Headwaters streams can be important areas of stream nitrogen retention. My dissertation research focused on evaluating the influence of wood in streams 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. I am conducting research in three watersheds across the northeastern United States: Hubbard Brook, NH; Sleepers River, VT; and Frost Valley (the Model Forest), NY.
At Hubbard Brook, we have a wood removal and a wood addition stream. The streams in this study are all small streams with north-facing watersheds. Wood removal was conducted in mid-October 2005.
At Sleepers River we have a pair of first-order streams with second-growth mixed hardwood-conifer riparian and upland forests. Measurements of stream Nitrate uptake were conducted in both streams three times during summer 2005 using a modification of the LINX II protocols for 15N-NO3- tracer additions. The first stream acted as the reference stream for our study and will remain un-manipulated. In the second stream nearly all wood in the stream channel was removed in September 2005, after the final pretreatment nitrate uptake measurement was conducted (excluding 4 pieces that were key in bank stability). In summer 2006, and 2007 we repeated the nitrate uptake measurements and compared the difference between SR-S and SR-N uptake before versus after the manipulation.
Beginning in Summer 2006 an addition set of three streams was established in Frost Valley, NY at the Model Forest. Pre-treatment data were collected in summer 2007 and fall 2007. Wood manipulations were conducted in fall 2007 after surveys were conducted. Post treatment data were collected in summer 2008 and fall 2008.
Collaborators
- Dr. Darren Bade
- Dr. Kristin Judd
- Dr. Gene Likens
- Dr. Clifford Kraft
Dana is an ecologist studying the bio-geo-chemical and structural influences on biological productivity in stream and river systems. He received his PhD from Cornell University in 2008. Dana is currently an NRC post-doctoral fellow at the NOAA Northwest Fisheries Science Center.