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05 August 2022 | Story Leonie Bolleurs | Photo Supplied
Marike Stander
For the first time in her life, Marike Stander accompanied a group of researchers for their annual relief expedition with the SA Agulhas II from Cape Town to Marion Island, where she assisted with fieldwork and data collection. Here she is pictured at the snow-covered Karookop.


The Prince Edward Islands are the most southerly part of South Africa’s official territory and consist of Marion Island and Prince Edward Island. On Marion Island, about 270 km² in size and situated in the sub-Antarctic Indian Ocean, 1 920 km from the South African shore, activities are restricted to research and conservation management. 

This is where Marike Stander, Lecturer in the Department of Geography at the University of the Free State (UFS), was granted the opportunity to assist a research group led by Prof Werner Nel (University of Fort Hare) and Prof David Hedding (Unisa) – based on her knowledge and experience in tracer sampling. 

Back home, Stander is working to complete her doctoral research, investigating the often-overlooked major issue of soil erosion. She believes the management of soil erosion, a global issue, is key. According to her, it impacts the storage of carbon and nutrients, and therefore the production of food, but it can also act as a pollutant in water sources.

Fieldwork and data collection

She was approached by the Sub-Antarctic Landscape-Climate Interactions (SANAP-LCI) Research Group, a project funded by the South African National Antarctic Programme-NRF. One of their research objectives is to explore the viability of using geochemical tracers in the substrate on Marion Island, the focus of Stander’s doctoral research. 

With the support of the UFS Faculty of Natural and Agricultural Sciences and the Department of Geography, she was released to accompany the research group for the first time in her life on their annual relief expedition with the SA Agulhas II from Cape Town to Marion Island, where she assisted with fieldwork and data collection. During this three-week field campaign, Stander collected sediment samples for the tracer project, as well as rock and peat samples.

With the SANAP-LCI group collaborating with research labs in the United Kingdom and France, she was able to bring her expertise to the table, while at the same time learning about other geochronological techniques and field methods.  

She was also excited about the exposure to the work of a myriad of researchers in various fields from around the world. Stander says in a time when the importance of interdisciplinary and multidisciplinary work is being emphasised, it was invaluable to meet and learn from various distinguished scientists.  “It changes your perspective and allows your mind to not only think outside the box, but also to think about all the interconnected boxes and how they affect each other.”

She believes being exposed to various sampling strategies from different scientists also broaden one’s skill set and experience. “Using your capabilities and skills in a different setting builds depth to your skill set and expands your horizon.”

Volcanoes and albatrosses 

Very few people get the opportunity to visit Marion Island. Thus, just the chance to visit and experience life on the island is described by many as one of their most memorable events. Always fascinated by volcanic features, Stander was completely captivated by this relatively young volcanic island. “There are so many interesting features, such as the pahoehoe and a’a lava flows, as well as the numerous scoria cones,” describes Stander, who cannot believe that she managed to cover the vast distances in gumboots, the only footwear that are effective to cross anything – from razor-sharp rocks to deep waterlogged mires.

She was also overwhelmed by the flora and fauna on the island.  “It is so very different from what we are used to and from what I’ve experienced before.  Seeing these animals in a relatively untouched remote location really captivated me,” she says. 

“More specifically, I fell in love with the albatrosses.  These remarkable seabirds cover vast distances over the ocean looking for food. They are unfortunately threatened by the invasive mice on Marion Island.” Stander invites people to help organisations such as Mouse-Free Marion to take on the difficult task of eradicating these mice. Find them at www.mousefreemarion.org.

On a lighter note, Stander also learnt a thing or two that was totally new to her. For instance, that there are radio telescopes installed on the radio-quiet Marion Island, searching for the universe’s first stars. And that male elephant seals that drive out all other male competitors during mating season are called ‘beachmasters’. She learned that these ‘beachmaster’ bulls have a harem of female elephant seals and can weight up to three tons.


• She wishes to thank Prof Werner Nel, Prof David Hedding, and Dr Liezel Rudolph (UFS) from the SANAP-LCI project for affording her the opportunity to join the expedition. She also thanks the SANAP-NRF and the Department of Forestry, Fisheries, and the Environment for making the expedition possible. 

News Archive

Research eradicates bacteria from avocado facility
2017-01-17

 Description: Listeria monocytogenes Tags: Listeria monocytogenes

Listeria monocytogenes as seen under an electron
microscope. The photo was taken with a transmission
electron microscope at the microscopy unit of the UFS.
Bacteriophages (lollipop-like structures) can be seen
next to the bacterial cells.
Photo: Supplied

“The aim of my project was to identify and characterise the contamination problem in an avocado-processing facility and then to find a solution,” said Dr Amy Strydom, postdoctoral fellow in the Department of Microbial Biochemical and Food Biotechnology at the University of the Free State (UFS).

Her PhD, “Control of Listeria monocytogenes in an Avocado-processing Facility”, aimed to identify and characterise the contamination problem in a facility where avocados were processed into guacamole. Dr Strydom completed her MSc in food science in 2009 at Stellenbosch University and this was the catalyst for her starting her PhD in microbiology in 2012 at the UFS. The research was conducted over a period of four years and she graduated in 2016. The research project was funded by the National Research Foundation.

The opportunity to work closely with the food industry further motivated Dr Strydom to conduct her research. The research has made a significant contribution to a food producer (avocado facility) that will sell products that are not contaminated with any pathogens. The public will then buy food that is safe for human consumption.


What is Listeria monocytogenes?

Listeria monocytogenes is a food-borne pathogenic bacterium. When a food product is contaminated with L. monocytogenes, it will not be altered in ways that are obvious to the consumer, such as taste and smell. When ingested, however, it can cause a wide range of illnesses in people with impaired immune systems. “Risk groups include newborn babies, the elderly, and people suffering from diseases that weaken their immune systems,” Dr Strydom said. The processing adjustments based on her findings resulted in decreased numbers of Listeria in the facility.

The bacteria can also survive and grow at refrigeration temperatures, making them dangerous food pathogens, organisms which can cause illnesses [in humans]. Dr Strydom worked closely with the facility and developed an in-house monitoring system by means of which the facility could test their products and the processing environment. She also evaluated bacteriophages as a biological control agent in the processing facility. Bacteriophages are viruses that can only infect specific strains of bacteria. Despite bacteriophage products specifically intended for the use of controlling L. monocytogenes being commercially available in the food industry, Dr Strydom found that only 26% of the L. monocytogenes population in the facility was destroyed by the ListexP100TM product. “I concluded that the genetic diversity of the bacteria in the facility was too high and that the bacteriophages could not be used as a control measure. However, there is much we do not understand about bacteriophages, and with a few adjustments, we might be able to use them in the food industry.”

Microbiological and molecular characterisation of L. monocytogenes

The bacteria were isolated and purified using basic microbiological culturing. Characterisation was done based on specific genes present in the bacterial genome. “I amplified these genes with polymerase chain reaction (PCR), using various primers targeting these specific genes,” Dr Strydom said. Some amplification results were analysed with a subsequent restriction digestion where the genes were cut in specific areas with enzymes to create fragments. The lengths of these fragments can be used to differentiate between strains. “I also compared the whole genomes of some of the bacterial strains.” The bacteriophages were then isolated from waste water samples at the facility using the isolated bacterial strains. “However, I was not able to isolate a bacteriophage that could infect the bacteria in the facility.

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