The effects of climate change on salinity and temperature of the Olifants and Breede estuaries, Western Cape Province South Africa

Abstract

Climate change and its negative impacts on ecosystem functioning on a global scale have recently become apparent. Climatic influences often negatively influence sensitive environments such as estuary’s ability to provide ecosystem goods and services. Further the effects of climate change on water quality within estuarine environments needs to be understood. The study has set out to determine if climate change has had an influence on physiochemical water quality characteristics both within and between the Breede and Olifants estuaries over a nine year monitoring period. Raw data for temperature, salinity and rainfall was processed in MS Excel in order to create time series line graphs and data tables which give insight in to changing physiochemical water quality characteristics and influences. The results obtained showed that water temperature remained constant throughout the entire monitoring period in both estuarine environments, where an inverse trend exists between rainfall and salinity. Further it was noted that drought conditions had been experienced throughout the entire Western Cape Province from 2017- 2019. One of the largest study limitations was the fact that numerous data gaps exist for temperature and salinity throughout the nine year monitoring period. These data gaps complicate data analysis and integrity. Overall, it was found that it cannot definitively be stated that climate change has had an effect within either estuarine environment during the study period. An extended monitoring period will however give better insight into whether climate change has had an influence on the estuarine environments. Better management practices are to be employed by the National Estuarine Management Programme to alleviate data gaps and equipment issues. Continued academic research, intensification of monitoring practices and more effective management are required to grasp a better understanding of the influence that climate change has on sensitive estuarine environments in the South African context.