COMPARISON OF SURFACE AND GROUNDWATER NUTRIENT LEVELS AND IMPACTS ON NET PRIMARY PRODUCTION IN SOUTHERN APPALACHIAN FENS

Nutrients are important drivers of net primary production, especially nitrogen (N) and phosphorus (P), but from where are southern Appalachian fens receiving those nutrients? Surface or groundwater? Throughout wetlands in the southern Appalachians surface water was sampled and hydrologic characterization was attempted. Wetland hydrology was characterized by precipitation data, soil moisture, and using channel dimensions along with flow speed to estimate water flow to the ecosystem. Groundwater was sampled in each wetland as well. Soil was examined in two parts: soil nutrient levels were compared with surface and groundwater nutrient levels to better understand nutrient flow through the system and soil texture was measured through particle size analysis. Finally, primary production was established through aboveground biomass harvest at peak standing biomass. Preliminary findings demonstrated that sites associated with gaining streams, where water is flowing through the wetland into the stream, had the highest net primary productivity (NPP) values (985 g C m-2). This trend could point to the importance of groundwater as a nutrient source. Sites associated with a losing stream, or stream fed, and sites with no surface flow had very similar productivity values (593 g C m-2 and 594 g C m-2, respectively). Sites where surface water was not an influence (gaining streams and no surface flow) had a strong negative correlation (r2 = 0.61) with soil moisture. NPP had a moderate positive correlation with % silt + clay. Nutrient analysis is forthcoming.