Unveiling Hidden Waters: Dr Thendo Mutshekwa’s Journey in Aquatic Ecology and Microplastics Research

Dimpho Lephaila
Apr 5
5 min read

What secrets do South Africa’s caves hold about microplastics? The answer lies at the heart of Dr Thendo Mutshekwa’s scientific journey.

An aquatic ecologist with a deep interest in the ecology of wetlands, reservoirs, and remote water bodies, Thendo hails from Tshiawelo, a village nestled in the lush, mountainous landscapes of Venda in Limpopo, South Africa’s northernmost province. His curiosity with science began at a young age. Fortunately, those around him recognised his passion and aptitude for science, nurtured his curiosity, and encouraged him to pursue it further.

Tracing nature’s hidden clues – Dr Thendo Mutshekwa ventures into remote waters in pursuit of answers few have thought to seek.

Despite this early interest, his career path wasn’t always clear. When he enrolled for an Environmental Science degree at the University of Venda, he wasn’t sure what direction he would take after graduation. Even during his Honours programme, uncertainty lingered.

Thanks to his academic mentors, Dr Florence M. Murungweni and Dr Tatenda Dalu, who played pivotal roles in guiding and shaping his career path into and through the field of aquatic ecology, where he found his niche.

“I realised that this was not just an area of study for me; it was a field I wanted to dedicate my career to, shaping my research around understanding and protecting freshwater environments.”

It was during his Master’s degree at the same university that Thendo’s passion for the dynamics of aquatic ecosystems truly solidified. This experience encouraged him to pursue a PhD, where he focused on assessing the effects of Macadamia Orchard pesticide inputs on recipient aquatic ecosystems.

Exploring Microplastics Pollution in Freshwater Caves

During his PhD, Thendo developed an interest in plastic pollution after reading published studies on the subject. Today, as a postdoctoral researcher at Albany Museum and Rhodes University, he investigates the complex interactions of remote water bodies, particularly in relation to pollution, biodiversity, and conservation.

Currently, he is working with Mr Musa C. Mlambo from Albany Museum in Makhanda, and Dr Samuel N. Motitsoe from Wits University, investigating microplastics pollution in South Africa’s freshwater caves, natural springs and sacred waters, an area that has received little research attention.

Their recent research explored how microplastics are accumulating in six freshwater caves in three South African provinces, and their potential impact on aquatic life, such as resident freshwater amphipods. These are the caves they examined:

Boesmansgat Cave: Also known as "Bushman's Hole," this deep submerged freshwater cave is located near Daniëlskuil in the Northern Cape province.
Bakwena Cave: Situated south of Pretoria in Gauteng province, this cave is located on the perimeter of the Agricultural Research Council Irene campus.
Sterkfontein Cave: Part of the Cradle of Humankind World Heritage Site, these limestone caves are located about 40 kilometers northwest of Johannesburg in Gauteng province, near Krugersdorp.
Kogelbeen Cave: Found on Kogelbeen Farm in the Pixley ka Seme District Municipality of the Northern Cape, it is the longest known cave in the province, extending 788 meters.
Peppercorn and Ficus caves are both situated on the northern slopes of the Makapansgat Valley (or Makapan Valley Fossil Hominid Sites of South Africa World Heritage Site, UNESCO), northeast of Mokopane in Limpopo province.

Dr Samuel Motitsoe (left), Mr Sanele Ndwandwe (center), Dr Thendo Mutshekwa (right), and Mr Musa C. Mlambo (far right) after microplastic sampling in Peppercorn Cave, Limpopo.

The research team’s findings, recently published in Hydrobiologia in a paper titled, Plastics Underground: Microplastic Pollution in South African Freshwater Caves and Associated Biota, revealed that microplastics are accumulating in some of these unique underwater ecosystems and are even being consumed by resident freshwater amphipod, Sternophysinx species .

“A surprising finding from our research was the presence of microplastics in freshwater caves with little direct human activity, like Kogelbeen Cave in the Northern Cape, suggesting underground water flow as a transport pathway. We also found microplastics in cave-dwelling invertebrates, showing their entry into subterranean food webs,” shares Dr Mutshekwa.

He explains that these caves support unique and sensitive aquatic life but are increasingly exposed to plastic pollution and intense human disturbances. Their study highlights the extent of microplastics contamination and emphasises the need for stronger conservation efforts and pollution management strategies to protect them from further degradation.

Building on these findings, Thendo is now expanding his research to other freshwater systems, including sacred waters and natural springs.

Learning, Adapting, and Making an Impact

Thendo’s journey has not only been about research but also about learning from his colleagues and mentors. Moving from Venda to Albany Museum and Rhodes University was a transformative experience, allowing him to collaborate with experts like Mr Musa C. Mlambo and Dr Samuel N. Motitsoe. Their dedication and expertise broadened his perspective and deepened his commitment to aquatic ecology.

“Finding a niche for my research and relocating to pursue my academic goals were significant challenges. Establishing myself in a specialised field like microplastics pollution required persistence, networking, and continuous learning. Moving to new institutions and adapting to different research environments pushed me to be flexible and proactive in building collaborations. Overcoming these challenges involved staying committed to my passion, seeking mentorship, and embracing new opportunities for growth.”

Beyond academic research, Thendo hopes his work will have a real-world impact. He hopes that assessing microplastics pollution and its associated risks will raise awareness and enable communities to understand the potential dangers of microplastics in freshwater systems.

“By assessing the occurrence of microplastics and their associated risks, my research aims to raise awareness within communities about their presence and potential hazards. This knowledge can inform the implementation of effective mitigation measures to safeguard freshwater ecosystems, protect aquatic life, and reduce health risks to humans.”

Dr Thendo Mutshekwa sampling in the Kogelbeen Cave, Northern Cape.

More Than a Scientist: Passion, Advice, and Reflections

Outside of his research, Thendo enjoys online gaming, watching soccer, and cycling, which helps him unwind and take a break from his scientific work. But if he weren’t a scientist?

“To be honest, I'm not entirely sure. It’s hard to imagine doing anything else, as my passion for science feels so central to who I am.”

For students and aspiring researchers interested in aquatic ecology, Thendo offers this advice:

“Stay curious and never stop learning. The field is constantly evolving, and there’s always something new to discover. Be persistent, and don’t be discouraged by setbacks, research is a journey of both challenges and breakthroughs. Build strong networks with colleagues, and always strive to make meaningful contributions that can improve our understanding of freshwater ecosystems and the challenges they face. Most importantly, stay passionate about protecting the environment, as it will fuel your work and inspire others.”

From exploring hidden waters to sharing knowledge – Thendo’s work echoes far beyond the field.

Looking back, Thendo acknowledges that his journey has been shaped by curiosity, mentorship, and persistence. His research continues to uncover hidden threats in freshwater systems, shedding light on pollution in places few people think to look.

As he expands his research to other freshwater ecosystems, one thing is clear – Dr Thendo Mutshekwa’s work is helping to bring critical environmental issues to the surface, ensuring that even the most hidden aquatic worlds are not forgotten.