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20 July 2020 | Story Leonie Bolleurs | Photo Supplied
The view from one of the offices in the Marion Island research station, with fresh snowfall in the interior of the island in the background.

Liezel Rudolph, lecturer and researcher in the Department of Geography at the University of the Free State (UFS), is strongly convinced that the Southern Hemisphere’s past glacial cycles will provide valuable insights to help predict and prepare for future climate change. Climate is changing fast and the magnitude of change we have seen over the last 30 years has taken a hundred or several hundred years to occur in the past. 

It is not only temperatures that are rising, but changes in wind patterns, rain cycles, oceanic circulation, etc., are also observed. As we do not know how the earth will respond or adapt to such rapid and drastic changes in climatic patterns, this poses various threats.

Link between landscape responses and climate change

Rudolph focuses her research on reconstructing the past climate of Marion Island. 

She had the wonderful opportunity to visit the island for the past three years with study and project leaders, Profs Werner Nel from the University of Fort Hare and David Hedding from UNISA, she departed on a ship to Marion Island to conduct fieldwork.They published their research findings of fieldwork conducted in 2017 and 2018.  

According to Rudolph, research in Antarctica, the Southern Ocean, and islands such as Marion Island is very important. South Africa is the only African country with research stations that have the ability to explore these regions.

“Marion Island has many landforms that could only have been created by glacial erosional or depositional processes, with glaciers currently absent from the island. To determine when the island was last in a full glacial period, we date the formation ages of these landforms.”

“In the short time we have been visiting the island, it was impossible to notice any drastic changes in the island climate. That is why we use these very old landforms to tell us more about periods before humans visited the island,” she says. 

Rudolph believes that understanding the link between landscape responses and climate change of the past can help to better predict some of the climate change processes that are currently threatening the planet.

“There’s a principle in geography called ‘uniformitarianism’, whereby we assume that the earth-surface processes we observe today, are the same as those that have been active in the past,” says Rudolph.

As scientists, they thus look at evidence of past geomorphic processes (which remain in the landscape in various forms, e.g. residual landforms, stratigraphic sequences, etc.) to piece together what the past climate was like. In the same way, they also use this principle to predict how certain earth processes will change in the future, along with climate changes.

“In return, we understand how the climate and the earth’s surface interact, and we can better predict how the earth will respond to climate change,” Rudolph adds. 

Society to play its part in climate change

In the long run, we as the public should play our part in readying society for the effects of climate change. 

Rudolph says society can play a positive role in terms of climate change by educating themselves with unbiased, scientifically sound information on the true state of climate change and by responding within their own spheres of influence.

“Don’t leave everything up to politicians and policy. As the public, you can start to make progress by assessing the effects that climate change may have on your industry, business or society, and strategise on how to adapt your processes to deal with these changes.”

“Be responsible with our natural resources, reduce your waste, support local businesses that are sustainable, and volunteer at a local environmental protection/clean-up organisation. All the small efforts will eventually add up to substantial change,” she says. 

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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