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Barking up the right trees on greenhouse gases


Content Team
24 March 2023

It is quite the career shift to trade marketing of one of the world’s most iconic surf brands to investigating the link between microbes, trees and greenhouse gas emissions. However, Southern Cross University biogeochemist, Dr Luke Jeffrey, is revelling in the contrast and producing world-leading discovery research.

A postdoctoral researcher in the Faculty of Science and Engineering, and recipient of the Chancellor’s Medal, Dr Jeffrey’s research into tree-based methane emissions – or treethane – represents a new frontier for the global methane and carbon cycles. What’s more, his game-changing discoveries are being made close to home in the wetlands of the far north coast of NSW.
“While wetland soils store vast amounts of carbon, they are also the Earth’s largest natural source of methane, a greenhouse gas that is about 45 times more powerful than carbon dioxide when it comes to warming our planet,” said Dr Jeffrey. “Our research has shown that wetland trees can emit substantial amounts of methane via their stems or trunks – a process that has been overlooked historically and globally.”

Dr Luke JeffreyDr Luke Jeffrey
Thanks to the discovery of a tiny and highly active ally, there is hope of significantly curbing treethane.
"Our research has uncovered thriving and abundant ‘methane-eating’ communities of bacteria living within the bark of the common Australian paperbark tree. These communities are ‘consuming’ the methane and converting it to carbon dioxide – a far less potent greenhouse gas – mitigating about a third of the total methane emissions.” 
Such is the importance of the discovery, in 2021 the United Nations recognised Dr Jeffrey’s research in its Panel on Climate Change Assessment Report 6, which shares latest scientific knowledge on climate change throughout the world. It has also been published in the esteemed journal Nature Communications.
“It is a major discovery for several reasons,” said Dr Jeffrey. “Firstly, the existence of these microbial communities in the bark raises questions as to whether similar processes occur in other trees and in other environments globally.
“Also, the research provides evidence that treethane may be an important and so far largely unaccounted for component of the local, regional and global carbon and methane budgets.”
“Thirdly, trees are not currently included as a distinct greenhouse gas emissions category, so with three trillion trees on the planet and a global mission to plant a trillion more over the coming decades, this kind of discovery and knowledge really is a game-changer in the drive to restore biodiversity while offsetting greenhouse emissions.”
Budgets of a different kind were part of Dr Jeffrey’s previous career travelling the world as Marketing Manager for surf company Billabong. It was the keen surfer’s dream job, but after twelve years he was looking for an ethical change. Ironically, it has turned out to be a tree change.
"I enrolled in an Environmental Science degree at Southern Cross University, then followed it with Honours and a Doctorate,” said Dr Jeffrey. “My PhD focused on determining the drivers and emissions of methane, carbon dioxide and groundwater from modified coastal wetlands and estuaries. That has branched off – so to speak – into the research I am doing now.”
Dr Jeffrey’s projects include collaborations with Monash University, University of Melbourne and the University of Western Sydney, with funding previously through an Australian Research Council Linkage Project grant and now an ARC Discovery Project grant. Another recently awarded grant – through the natural sciences-based Hermon Slade Foundation – is supporting novel investigation into microbial influence on nitrogen fixation in trees throughout Australia.
 “Nitrogen fixation is the process of converting atmospheric nitrogen gas into compounds that are usable by plants. We know this naturally happens in soils and is critical for life on Earth,” he said. “Through this research grant, we will determine whether trees also contain microbes that can fix nitrogen. If this is so, the global nitrogen cycle may need a rethink.
“Because fixed nitrogen can encourage healthy plant growth, there may also be implications and applications for agriculture. In all these areas, our team at Southern Cross University is leading ‘new frontier’ research and the possibilities are very exciting.”

Video: 'Treethane': A New Frontier in the Global Carbon Cycle?

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