Evaluation of hourly physico-chemical data between 2012 and 2015 from two permanent probes on the Berg River Estuary, Western Cape, South Africa

Abstract

Climate change is affecting ecosystems all around the world, and estuaries are no exception. Because estuaries are rich in nature, it will be one of the most impacted elements by these climatic alterations, both in terms of structure and dynamics, with clear consequences for the estuary ecological health. This mini thesis aimed to study the effects of climate change on the Berg River estuary. The Berg River Estuary is a coastal outlet located on the West Coast of South Africa. Over three hydrological years (2012 to 2015), a multidisciplinary case study of the estuary was undertaken, monitoring the dynamic reactions of temperature, salinity, mean flow and sea level behaviour to long-term climatic variability patterns, at two sites (Berg 2 and Berg 4). Trends, patterns, and periodicity in natural cycles were identified using Microsoft Excel and SPSS. The data was categorised into two categories, High flow (HF) and low flow (LF). Data from temperature, salinity, mean flow, and estuarine water level were cross correlated as a probable driving mechanism for climatic changes. The data revealed that there was a significant change (increase) in temperature in the months of LF for the three hydrological years studied. Also, there was an increase in the temperature of estuary in the months of HF across the years. However, after statistical analysis, the increase in temperature was not deemed significant. Correlation analysis of mean flow and salinity data shows significant (95%) correlations. Also, there exist a significant (>95%) correlation (negative) between salinity and mean flow. This study identifies potential driving mechanisms of estuary perturbation and whilst causal mechanisms can only be proposed, these observations can form a baseline for future targeted modelling, monitoring and management. Lastly, some recommendations are made for the future monitoring and management of this estuary.