Sediment geochemistry and short-term biomanipulations in Emigrant Creek Dam, New South Wales, Australia

Sediment geochemistry and short-term biomanipulation of Emigrant Creek Dam (ECD), a freshwater reservoir, New South Wales, Australia, were investigated to assess perturbation of the aquatic environment. Sediment concentrations of As, P, N, Cd and Mn were substantially above background, predominately bioavailable, and spatially associated with Emigrant Creek inflows and anthropogenic sources within the reservoir. Benthivorous carp (Cyprinus carpio L) biomanipulations had immediate “bottom-up” effects on water quality leading to a proliferation of heterocystous cyanobacteria Anabaena spp. Hence, point source input reductions and carp eradication should improve reservoir water quality; these are fundamental management approaches to restore and maintain eutrophic subtropical reservoirs.