Kariega’s Carla Dodd earns PhD from NMU for research on groundwater
Few people can claim to know more about the seriousness of a drought than Nelson Mandela Bay residents and even fewer can argue with Dr Carla Dodd, who received her doctoral degree in geology yesterday.
Dodd received her degree at the Nelson Mandela University autumn graduation ceremony for her research into the little understood origin, chemistry and complexity of groundwater from source to sea in the Nelson Mandela Bay region.
The research provides the first groundwater quality baseline related to coastal springs in a region beset by drought.
Dodd said for her research she had used microbialites — rock-like underwater structures which resemble reefs made entirely of millions of microbes — as easily accessible monitoring systems for the quality of groundwater which emerges from the coastal springs in the metro and is found to be contaminated by wastewater.
“During the prolonged drought in the metro, [there were] increasing amounts of groundwater [water in underground aquifers, as opposed to the surface water from rivers wetlands and lakes],” she said.
“Having been extracted for domestic and municipal use, the problem was that we did not know where the groundwater discharging at the coast was coming from. Also how its composition is influenced by flow paths, both from a geological and anthropogenic [human-related pollution] point of view.”
Her study has been presented internationally and claimed the 2023 National Research Foundation Research Excellence Award for Next Generation Researchers as well as the South African Women in Science — Ndoni Mcunu Fellowship award from the department of science and innovation.
Dodd said her fascination with geology had started in high school at an NMU science week programme and after matric she had been offered a bursary to study geology at the university, where she has remained in the department of geosciences ever since.
The goal of her research was to ultimately contribute to a better understanding of the groundwater sources from source to sea while ensuring that the aquifer systems were managed responsibly for the benefit of residents and the environment.
To establish this, she worked with a hydrogeologist from the University of Oldenburg, Germany, and a marine geologist from the Council of Geoscience in SA.
“For my research, I looked at using the microbialites as easily accessible monitoring systems for the quality of groundwater that emerges from the coastal springs here.
“Which we found to be contaminated by wastewater,” Dodd said.
Dodd’s co-supervisor, Dr Gavin Rishworth, who is from the department of zoology at NMU and specialises in microbialite ecosystems, said microbialites improved the quality of water, helping to purify it like a wetland.
“They are an amazing resource, a saving grace from the water quality aspect and the scientific value they add to our coastal zone,” Rishworth said.
Dodd said Rishworth had been instrumental in her research path.
“He is a global expert in microbialite systems, and I would not be where I am today without him.
“He co-supervised my honours and master’s and was the main supervisor of my PhD.”