Aspects of the phosphorus cycle in Hartbeespoort Dam (South Africa)

Abstract

The role of biotic processes in a warm, monomictic, hypertrophic African impoundment (Hartbeespoort Dam) is examined using 32 P radiobioassays . Phosphorus demand is assessed by phosphorus turnover times, alkaline phosphatase activity, cellular phosphorus status and the phosphorus deficiency index . Long turnover times indicative of an enriched system were recorded, ranging from 9 h to 1992 h, with no evidence of phosphorus stress being present . These turnover times support the hypothesis that the phosphorus cycle in Hartbeespoort Dam is dominated by the algal community which is shown to play an important role in phosphorus cycling within the water column . However, hydrological processes remain the driving force in phosphorus seasonality in the lake .

Ecological Problems in Hartbeespoort Dam

“…This also allows development of surface accumulations that can eventually build into dense hyperscums at sheltered sites (Zohary 1985). Anaerobic conditions, decomposition and photo-oxidation processes within these hyperscums release foul smelling gases which have been the subject of much public complaint in addition to adverse aesthetic considerations and impaired recreation (Thornton 1987).…”