Consequences of nitrogen fertilization and soil acidification from acid rain on dissolved carbon and nitrogen stability in the unglaciated Appalachian Mountains
Taylor PG. 2008. Consequences of nitrogen fertilization and soil acidification from acid rain on dissolved carbon and nitrogen stability in the unglaciated Appalachian Mountains. Virginia Polytechnic Institute and State University
The expansion and proliferation of reactive nitrogen (N) sources, predominantly fertilizer application and fossil fuel combustion, has enriched the earth with N and acidified ecosystems. Acid rain is a primary vector of both N fertilization and acidification, initiating a cascade of consequences that alter biogeochemical cycling and global biological structure and function. Studies on N and acid influences are how ever rarely linked despite their common source. We used a wide, chronic gradient of N deposition (5.5 – 31 kg N ha-1 yr-1) to explore patterns in carbon (C) and N cycling in light of recognized biogeochemical responses to acidic deposition. Specifically, we examined the response of key controls on dissolved C and N stability because soluble pools are involved in decomposition and nutrient recycling, the formation of soil organic matter (SOM), and the translation of elements through the biogeochemical continuum from atmospheric to soil to water. Results suggest that N deposition led to reduced organic matter C/N, enhanced net nitrification, and greater DON generation; and, these patterns were associated with changes in C composition. Conversely, physiochemical processes in the mineral soil seemed to control organic matter dynamics, with effects onN processing. Moreover, pH dependent controls on DOC stability were evidenced by changes in DOC concentration, chemical complexity and recalcitrance. These horizon specific,differential responses to acid rain indicate that changes in the forest floor N economy were responsible for increased surface water NO3-N concentrations, where as enhanced organomineral stability of DOC caused a significant increase in DOM concentrations in export.
- Type
- Academic
- Authors
- Taylor, Philip
- Date of Issue
- 2008-02-04
- Publisher
- Virginia Polytechnic Institute and State University
- Units
- GRSM
- Keywords
- Acid Rain, Appalachian Mountains, Balsam Mtn, Biogeochemistry, Carbon, Clingmans Dome, Cosby, Deep Creek, DINe, DOC, don, GRSM-00444, Mt. Collins, Mt. LeConte, Newfound Gap, Nitrogen, Nitrogen Deposition, Nutrient Cycling, Soil, soil acidification, temperate ecosystems, thesis
- Subjects
- Ecological Framework: Air and Climate | Air Quality | Wet and Dry Deposition , Ecological Framework: Geology and Soils | Soil Quality | Soil Function and Dynamics