Research Project Summary Information
Deacidification - Dissolved Organic Carbon & Nitrate Export- Identifying Connections (ST10662-1)
The Adirondack and Catskill regions of New York receive some of the highest rates of atmospheric deposition of nitrogen (N) in the country. Effects of N deposition on ecosystem processes include impacts on decomposition, loss of biodiversity, poor air quality (as NOX-facilitated O3 production), global warming (as N2O), acidification of soils and surface waters (as NO3-), and coastal eutrophication. When NO3- leaches from soils to drainage waters, it contributes to soil acidification by removing base cations from soil exchange sites, and contributes to surface water acidification when supplies of base cations do not suffice to match rates NO3- export, under either chronic or episodic conditions.
Nitrate concentrations in surface waters have decreased across the NE since the early 1990s. Many hypothesis have been proposed, but the cause is still unclear. One control may be associated with increasing abundance of dissolved organic carbon (DOC), which in turn may be an unanticipated result of soil recovery from acidification. Variations in surface water DOC concentrations are sometimes associated with large effects on watershed nitrogen retention. Policy and management decisions regulating NOX emissions require understanding of the controls on the decadal-scale patterns of N retention and loss, which currently cannot be fully explained.
Soil and surface water chemistry will be compared across 10 catchments from a range of watersheds in long-term-monitoring networks in the Catskills and Adirondacks to identify the role of soil production and consumption processes in driving cross-watershed differences in DOC and nitrate loss, or whether other factors explain the relationship. A series of lab experiments and new data collection at the Woods Lake liming study will identify the role of acidification and de-acidification in driving the net production of DOC and nitrate. The PnET-CN model of forest C, N, and water balance will be modified to include DOC production and movement in soils, and model analyses will test whether inclusion of DOC processes improve model capacity to capture declines in surface water nitrate concentrations in the 1990s.
This project will complement long-term records of surface water chemistry at sites in the Adirondacks and the Catskills with new measurements and modeling activities. The work will address the roles of DOC and changing pH in soils as possible controls on net nitrate availability in forest soils, to better understand the connections and interactions among nitrogen deposition, ecosystem acidification/de-acidification, and hydrologic exports of DOC and nitrate.
130 Humphreys Service Bldg
Ithaca, NY 14853
Environmental Monitoring & Research
NYSERDA Contact Information
R&D - Environment & Energy Res