The effect of sewage on the distribution of seaweed at the Bats Cave east bank sewage outfall in East London, South Africa

Abstract

In order to determine which seaweeds were unable to survive in the stressed area and how far the effect of the effluent extended along the coast, various methods were applied and carried out over a two-year period between November 1982 and November 1984. Three major long-term studies took place. The first study was to determine the presence or absence of the seaweeds throughout (1) the entire study area and then (2) in areas broken up into sections with known distances from the outfalls. The second method involved statistical evaluations using point intersect methods and photography to produce information to determine species density, diversity, evenness, and to provide the information required to work with a number of ecological equations in the future. The third method incorporated a long-term survey on cleared plots in various sectors of the study area. The recolonization of the plots was recorded over a thirty-week period. (par. 1.1, p. 6-7)