African Wildlife & Environment Issue 84 2023

CONSERVATION

A view of the water from the Hartbeespoort dam wall

greater biomass than low levels of nutrients. This is an important scientific principle – known as a mass balance – that the reader needs to grasp, because it lies at the heart of the argument being presented that the removal of hyacinth is potentially harmful to human health. The mass balance matters so we all need to understand it better. Noting the fundamental principle of the mass balance in Reason #1, if the nutrient levels are elevated, and the resultant floating biomass is removed, all this does is to eliminate competition for suspended biomass, by enabling direct sunlight to stimulate single celled algae. Therefore, the removal of the floating Reason #2:

biomass by artificial means, merely converts the mass balance in favour of suspended biomass such as single celled algae.

Reason #3:

Knowing that our dominant genera of single celled algae in HAB waters of South Africa are Anabaena and Microcystis , both of which produce potent toxins known to have a range of human health implications, a rational choice would be to tilt the mass balance in favour of floating biomass rather than suspended biomass of an equal quantum.

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