Spatial variability of the stable isotope (<i>δ</i>¹⁵N) composition in two freshwater bivalves (<i>Corbicula fluminea</i>and<i>Elliptio complanata</i>)

Abstract

We compared the isotopic composition in freshwater bivalves (Corbicula fluminea and Elliptio complanata) from streams with different nitrate concentrations in a North Carolina river basin. Nitrogen isotopic (δ 15N) tissue values of C. fluminea and E. complanata were significantly higher in an agricultural land-use stream site compared to urban and forested samples (p < 0.05). Nitrogen (δ 15N) tissue values for both species were significantly (p < 0.001) associated with land-use type or patterns. The potential use of resident, non-native bivalves as biomonitors of potentially harmful nitrogen levels was implied.