Eutrophication and cyanobacteria in South Africa’s standing water bodies: A view from space

Mark W Matthews,Stewart Bernard

doi:10.17159/sajs.2015/20140193

Abstract

Satellite remote sensing can make a significant contribution to monitoring water quality in South African standing water bodies. Eutrophication, defined as enrichment by nutrients, and toxin-producing cyanobacteria (blue-green algae) blooms pose a significant threat to the quality of South African surface water bodies. The status and trends of chlorophyll a (chl-a, a proxy for eutrophication), cyanobacterial blooms and cyanobacterial surface scum were determined for South Africa’s 50 largest water bodies between 2002 and 2012, using a recently developed algorithm and 10 years of data from the Medium Resolution Imaging Spectrometer (MERIS) satellite. The majority (62%) of the 50 water bodies were highly nutrient enriched or hypertrophic, while 26 had cyanobacterial blooms which posed a high health risk from surface scums. This study is the first of its kind to provide quantitative water quality information for South Africa’s water bodies from a time series of satellite remotely sensed data. We demonstrate the pivotal role that satellite remote sensing can play in greatly supplementing in-situ monitoring efforts such as the National Eutrophication Monitoring Programme. The finding that many water supply bodies are severely impacted by eutrophication and cyanobacterial blooms confirms that these remain issues of critical concern for water security and supply in South Africa.

Highlights

Price elasticity measures the sensitivity of consumer behaviour to price fluctuations. (It should be noted that electricity prices in South Africa are administratively set and are tariffs, but here we use the terms interchangeably.) Understanding such behavioural responses is of strategic and practical importance to policymakers and investors alike within the electricity sector when considering infrastructure development planning, the determination of future electricity tariffs, environmental policies, etc
Eskom and National Energy Regulator of South Africa (NERSA) have changed the electricity tariff structure resulting in increases of up to 25% per annum from 2008 to date
In a monopolistic set-up such as the South African electricity supply sector, the supply curve is the marginal revenue curve, only that portion thereof that lies above the marginal cost curve

Summary

Introduction

Price elasticity measures the sensitivity of consumer behaviour to price (or tariff) fluctuations. (It should be noted that electricity prices in South Africa are administratively set and are tariffs, but here we use the terms interchangeably.) Understanding such behavioural responses is of strategic and practical importance to policymakers and investors alike within the electricity sector when considering infrastructure development planning, the determination of future electricity tariffs, environmental policies, etc. Price elasticity measures the sensitivity of consumer behaviour to price (or tariff) fluctuations. (It should be noted that electricity prices in South Africa are administratively set and are tariffs, but here we use the terms interchangeably.) Understanding such behavioural responses is of strategic and practical importance to policymakers and investors alike within the electricity sector when considering infrastructure development planning, the determination of future electricity tariffs, environmental policies, etc. Being able to determine the most likely behavioural responses to changes in prices in an industrial environment that is continuously becoming more electricity intensive[1] is the key to successful policy implementation. South Africa experienced a severe electricity supply crisis during 2007/2008 with extensive blackouts or loadshedding. The damaging consequences on the economy were vast. Many possible reasons have been given to explain the crisis, such as the lack of capacity for generation and reticulation of electricity[3] and the lack of research on electricity topics and energy in general[4]

Objectives

Methods

Findings

Conclusion