Coral reefs are under increasing threat owing to global climate change, and their protection requires novel insight into their biophysical functioning.
Dr Calvin Wells was awarded a PhD in Civil Engineering from UKZN for research that used the principles of environmental fluid mechanics to show how the interaction between global ocean circulation and the continent of Africa protects the Sodwana Reef system from high ocean temperatures.
Titled: “On the Cold Water Temperature Anomalies Along the Coral Reefs at Sodwana Bay, South Africa”, his thesis was supervised by Professor Derek Stretch and Dr Justin Pringle.
His insights can be used to promote the sustainable management of coral reefs, locally and globally.
‘I have always enjoyed the way the Environmental Fluid Mechanics Department at UKZN approaches research and the projects they take on are always interesting and complex,’ said Wells. ‘When the opportunity arose to do research into the health and functioning of the coral reefs along our coastline, I jumped at the chance.’
Wells said that many coral reef systems around the world have already begun to experience significant coral bleaching related to the effects of warming events associated with climate change and other adverse impacts such as pollution and human activities.
‘However, Sodwana Bay, along the northeastern coast of South Africa, has shown resilience to coral bleaching, attributed to strong ocean mixing and short-term cold water temperature anomalies identified around the Sodwana region,’ he said. ‘My research investigated the complex hydrodynamic features that drive these temperature anomalies and how they influence the sustainability of higher latitude coral reefs.
‘Compared to other coral reefs around the world, the Sodwana reef system is a pristine and healthy coral system and seems to escape the significant coral bleach events that impact coral communities globally,’ said Wells. ‘By understanding why our corals are spared during these events, we will gain valuable insight into how marginal reefs will respond to constant changes in the global climate and where to focus our efforts in the future to save our corals as ocean temperatures continue to rise.’
Wells, who has always had a passion for the ocean and the environment, said that his research allowed him to explore both those fields within an engineering context. The work also allowed him to scuba dive – one of his favourite pastimes!
‘One standout feature of Calvin’s PhD work was the wide scope of challenges faced in order to undertake his fieldwork,’ said Stretch, ‘including difficult diving work at the Sodwana reef complex in order to deploy and retrieve monitoring instrumentation.’
Stretch said that Wells needed to learn entirely new technical skills to develop a new type of instrumentation for extended deployment time periods: namely the tilt-current meters needed to continuously monitor flow speeds and direction on the reef complex.
Wells developed a detailed and complex numerical model to reproduce and explain his observations concerning recurring temperature anomalies at the Sodwana coral reef complex. ‘These models will be important for the sustainability of the coral reefs,’ said Stretch.
Wells has already produced several publications in leading journals in the field. He is currently a Director of the coastal engineering and environmental consultancy, CCS Consulting. He thanked his supervisors for their professional and personal support.
Words: Sally Frost
Photograph: Supplied
