In profile: Liza McDonough, PhD Student

Liza McDonough has always had an interest in the environment. As a child, she found nature, geology and environmental processes fascinating, so it was no surprise that she went on to complete a Bachelor of Environmental Science at UNSW.

During her honours year, Liza studied carbon in methane and carbon dioxide within a cave system, looking at different types of carbon atoms—known as isotopes—and their concentrations.

“I find it incredible that we can measure the concentrations of different isotopes of atoms that are invisible to the naked eye and use this to understand the source and age of carbon in a water sample, and what processes it has been subjected to over time,” says Liza.

After a stint in environmental consulting, Liza returned to UNSW to complete her PhD, excited to be able to delve back into in-depth research on a topic she was passionate about.
Her PhD investigates organic carbon sources and sinks in groundwater systems, a topic relevant today with the depletion of groundwater resources expected due to climate change and over-extraction.

“Groundwater quality is becoming increasingly important to understand, and groundwater quality largely depends on its concentration of dissolved organic carbon,” says Liza.
“Using isotopic analyses and carbon characterisation techniques, we are able identify groundwater carbon sources, the components of organic carbon that are degraded over time along a groundwater flow path, and the mechanisms and rate of removal.”

Liza says that most previous research on organic carbon has focused on surface waters, so the transport and fate of dissolved organic carbon in groundwater and aquifers is still unclear.

Moreover, the capture and storage of carbon has become a hot topic as a potential means to mitigate fossil fuel emissions, and Liza’s research will help to enable effective management of groundwater as part of the carbon economy.

Liza’s project is supervised by Professor Andy Baker, Dr Martin Andersen, Dr Denis O’Carroll, Dr Karina Meredith and Dr Helen Rutlidge—and funded by the Australian Research Council.

It is highly collaborative, with Liza working with the Australian Nuclear Science and Technology Organisation (ANSTO)—who provided her with a scholarship to assist with isotopic analyses—as well as UNSW’s Mark Wainwright Analytical Centre and other universities and institutions.

“We’ve been collaborating with Southern Cross University and British Geological Survey to compile a global dataset of groundwater dissolved organic carbon concentrations which will form part of a paper we are aiming to publish this year,” said Liza.

“We’re also working closely with Florida State University, who are analysing our groundwater samples using an ultra-high resolution mass spectrometry technique.”

Liza says that the highlight of her research has been the opportunity to contribute to scientific understanding of the environment.

“My overarching goal is also to discover better ways of managing the environment for its preservation. Ultimately, I’d like to pursue a career in government or academia that allows me to further my contribution,” says Liza.