A LIMNOLOGICAL SYNOPSIS OF BHANGAZI SOUTH, A DYSTROPHIC COASTAL LAKE IN THE GREATER ST LUCIA WETLAND PARK (KWAZULU/NATAL), WITH COMMENTS ON ITS CONSERVATION VALUE.

Abstract

Summary Base-line limnological and biological data are given for Lake Bhangazi South, a small lake on the coastal plain of Kwazulu-Natal, South Africa. This shallow (Zmax < 6 m), subtropical lake is a warm and seemingly continuously polymictic system, but experiences severe (continuous?) deoxygenation of its deeper muddy sediments. Nutrient status (of N in particular), light attenuation, phytoplankton productivity and zooplankton biomass are high relative to other regionally comparable coastal lakes investigated. While the ichthyofauna is quite rich, zooplankton and especially zoobenthos communities are species-poor, and lack the relict estuarine components which often dominate these latter assemblages in comparable coastal lakes. The zooplankton is typically freshwater in composition, and contains a new species of copepod (Tropodiaptomus bhangazii Rayner); the lake may be older, or seen longer evolutionary divergence than its proximate counterparts. Benthic species diversity in the lake is especially low...