Over recent decades the frequency, magnitude and extent of harmful algal blooms (HABs) have increased globally in estuarine and coastal waters. Embedded in the definition of eutrophication, anthropogenic nutrient loading (e.g. agricultural, domestic and urban runoff) is the key culprit responsible for the increased incidence of HABs. The primary concern arising from such HAB events is founded in the array of possible consequences. Some of these include oxygen depletion related to bloom decay processes, direct toxic effects on higher trophic levels, mechanical interference and suffocation of faunal communities and habitat destruction through shading of submerged aquatic vegetation.
The aim of this talk is to showcase examples of various HAB species documented in South African estuarine and coastal waters, and to delve into the drivers and mechanisms associated with their occurrence.