Assessment of a δ 15 N Isotopic Method to Indicate Anthropogenic Eutrophication in Aquatic Ecosystems

作者：Marci L. Cole, Iván Valiela, Kevin D. Kroeger, Gabrielle L. Tomasky, Just Cebrián, Cathleen Wigand, Richard A. McKinney, Sara P. Grady, Maria Helena Carvalho da Silva · 发表于：Journal of Environmental Quality · 年份：2004 · DOI：10.2134/jeq2004.1240 · 被引用次数：293 · 研究领域：Isotope Analysis in Ecology、Coastal wetland ecosystem dynamics、Marine and coastal ecosystems

Increased anthropogenic delivery of nutrients to water bodies, both freshwater and estuarine, has caused detrimental changes in habitat, food web structure, and nutrient cycling. Nitrogen-stable isotopes may be suitable indicators of such increased nutrient delivery. In this study, we looked at the differences in response of macrophyte delta15N values to anthropogenic N across different taxonomic groups and geographic regions to test a stable isotopic method for detecting anthropogenic impacts. Macrophyte delta15N values increased with wastewater input and water-column dissolved inorganic nitrogen (DIN) concentration. When macrophytes were divided into macroalgae and plants, they responded similarly to increases in wastewater N, although macroalgae was a more reliable indicator of both wastewater inputs and water-column DIN concentrations. Smooth cordgrass (Spartina alterniflora Loisel.) Delta15N increased uniformly with wastewater inputs across a geographic range. We used the relationship derived between S. alterniflora and relative wastewater load to predict wastewater loads in locations lacking quantitative land use data. The predictions matched well with known qualitative information, proving the use of a stable isotopic method for predicting wastewater input.