Variation in stable isotope signatures of the submersed macrophyte Vallisneria natans collected from several shallow lakes in China

Abstract

We examined the stable carbon and nitrogen isotope variation in the submersed macrophyte Vallisneria natans in several shallow Chinese lakes relative to physicochemical parameters of the lake water and V. natans tissue. Of the parameters examined, the δ 15N values of V. natans were correlated only with different inorganic nitrogen concentrations in the water column, suggesting that V. natans could be a sensitive bioindicator for monitoring nitrogen input into lakes. The δ 13C of V. natans varied widely and was correlated only with the inorganic carbon concentration of the water, possibly reflecting complex photosynthetic fixation and adaptations of V. natans to utilize inorganic carbon sources of different types.