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Assessing the Impact of Wet and Dry Nitrogen Deposition as an Ecosystem Stressor at
Marine Corp Base Camp LeJeune (MCBCL), Jacksonville, North Carolina

Wayne P. Robarge*
North Carolina State University, Department of Soil Science, Raleigh, NC 27695-7619

Karsten Baumann
Atmospheric Research & Analysis, Inc., Cary, NC 27513

Patricia Cunningham
RTI International, Research Triangle Park, NC 27709

Susan Cohen
DCERP Coordinator, Marine Corp Base Camp LeJeune, NC 28543


Long-term sustainability of our nation’s military training bases is of critical importance to national security. In addition to training, which is the primary mission of most military bases, many military installations face land-use pressures due to assignment of increased military personnel, frequency and intensity of training, and proximity to growing urban areas and the resultant inability to expand in physical size (encroachment). Compliance with the Endangered Species Act and protection/generation of native habitats present additional pressures. This project is part of a larger effort, the Defense Coastal/Estuarine Research Program (DCERP) funded by the Strategic Environmental Research and Development Program, to identify significant ecosystem stressors and develop conceptual and mechanistic ecological models that will lead to effective management guidelines for the long-term sustainability of MCBCL near Jacksonville, N.C. MCBCL occupies over 60,000 ha in eastern North Carolina and extends from the Atlantic Ocean inland for ~ 24 km. MCBCL also constitutes a significant fraction of the New River watershed, which flows through the middle of the base. Wet deposition of nitrogen (N) will be monitored for 2 years using 4 National Atmospheric Deposition Program (NADP) style wet-dry collectors deployed along a transect across MCBCL from the Atlantic Ocean to Jacksonville, NC, which encroaches the base from the north. Sample collection, preservation and analysis will follow NADP guidelines, except that analysis of total dissolved organic-N will also be included in all analyses. Dry deposition of reduced and oxidized N species will be indirectly determined using throughfall/stemflow measurements within representative vegetative canopies at MCBCL (pine flatwoods, dry longleaf pine-wiregrass savanna, hardwoods). These measurements will be supplemented with passive samplers (ALPHA® samplers) to determine weekly average values of ambient ammonia and nitric oxide atmospheric concentrations, and with a network of tipping bucket gauges to measure rainfall amount along three transects across MCBCL. Repeated measures analysis will be used to assess concentration data and then combined with response surfaces generated from tipping bucket data to produce nutrient deposition maps. This combined approach will allow the assessment of the magnitude and temporal/spatial trends in N deposition (wet and dry) to the vegetative canopies and underlying soilgroundwater ecosystem across MCBCL. It will also provide baseline estimates of N deposition to compare local remobilization and deposition of N as a result of prescribed burning, which is a common land management practice in the Southeastern US and on MCBCL. This project will also estimate the magnitude and long-term trends in N deposition to the surrounding aquatic/estuarine ecosystems.