Metal and phosphorus accumulation in the benthic algae of a eutrophic river

Eutrophication, resulting from excess nutrients, is a common problem in surface water systems and has been related to fish skeletal deformities, fin erosions, lesions and tumors (DELT anomalies) in the Little Miami River (LMR). Hypothetically, metals accumulated in benthic algae are transferred through the foodweb to fish and contribute to failed developmental and immune system processes that normally prevent DELT anomalies. The purpose of this research was to document the extent of eutrophication in the LMR and analyze the relationship between eutrophication, eutrophic response variables and metal accumulation at the base of the aquatic foodweb.; A field study of eutrophic and chemical parameters indicated the LMR is burdened with excess phosphorus, benthic algal biomass that borders on nuisance growth, excess benthic phosphorus storage, and high daytime dissolved oxygen (DO) concentration. Periphyton phosphorus (P) was the only eutrophic response variable to correlate with the distribution of fish anomalies reported by OEPA, and the association was negative rather than positive. We concluded that aqueous nutrients, eutrophic response variables and/or water chemistry alone did not explain the occurrence of fish anomalies in the LMR.; Metal concentrations in LMR periphyton were analyzed in association with eutrophic response variables. Results showed a significant relationship between eutrophic response and the amount of metal accumulation in LMR periphyton. Specifically, aqueous nitrogen explained between 12% and 59% of the variation in periphyton metal concentration. Aqueous P, DO, pH, periphyton P and periphyton biomass were also correlated with periphyton metal concentrations when data were examined by multiple regression analysis.; Experiments were conducted to analyze the relationship between benthic algal metal accumulation and increasing phosphorus concentrations under controlled conditions. Results showed that no one nutrient or eutrophic response variable was the best predictor of metal accumulation in benthic algae. Rather, the interaction of nutrients and eutrophic response variables explained between 32% and 69% of the variation in periphyton metal concentration.; This research documented that the relationship between surface water eutrophication and its associated response variables enhances metal accumulation in the aquatic foodweb in both a field and laboratory environment.