Emma’s research is helping pave the way for Australia’s seaweed industry
A passion for marine life led CQUniversity graduate Dr Emma Theobald to move from the United Kingdom to Gladstone to undertake her PhD at the Coastal Marine Ecosystems Research Centre (CMERC), where her research is helping unlock the potential of seaweed in reducing methane emissions.
Dr Theobald spent several years researching Asparagopsis taxiformis, a native red seaweed that has been attracting global attention for its ability to reduce methane emissions from livestock. Her research focused on solving some of the key challenges that have so far prevented the seaweed from being cultivated at a commercial scale.
“Around 12 years ago researchers discovered this seaweed can dramatically reduce methane emissions, a potent greenhouse gas that contributes to climate change,” Dr Theobald said.
“Including a small amount of this seaweed in the diet of cows largely stops them from burping methane into the atmosphere.
“Methane from cattle accounts for around 40 per cent of Australia’s methane emissions and about 10 per cent of our greenhouse gas emissions.
“Tackling that at the source could be a valuable step towards reducing emissions and meeting climate goals.”
Supported by the Australian Seaweed Institute, Dr Theobald’s PhD explored how to reliably cultivate Asparagopsis for ocean farming, a necessary step for commercial-scale production.
“If Australia wants to use Asparagopsis to help reduce livestock emissions, we first need reliable ways to grow enough of it,” she said.
“My research helps solve one piece of that puzzle.”
Reliable germling generation key to production
One of Dr Theobald’s research achievements was developing methods to consistently produce seaweed ‘germlings’, the tiny juvenile seaweeds used to establish ocean farms.
“Asparagopsis can be farmed on land in tanks or ponds, or in the ocean,” she said.
“One of the most practical ways to establish an ocean farm is by seeding ropes with tiny juvenile seaweeds, called germlings, before deploying them into the ocean to grow.
“My research explored how to induce Asparagopsis to reproduce so that a reliable supply of germlings could be generated and then assessed different twine materials to see which best supported their growth and survival.
“Reliable reproduction and cultivation methods are essential if ocean farming is going to become commercially scalable.”
Her work not only identified the cultivation conditions required to consistently trigger reproduction and generate large numbers of germlings but determined that polypropylene and cotton twines were among the most promising substrates for retaining young seaweeds.
Managing Colaconema contamination
Like much scientific research, the project also involved overcoming unexpected challenges.
“One of the biggest challenges was contamination,” Dr Theobald said.
“You’re creating a perfect growth environment for your seaweed to thrive, but there are usually lots of other species that are keen to capitalise on that environment too.
“Initially, my seaweed cultures became contaminated with a tiny red seaweed called Colaconema, which can eventually spread and become very problematic.
“Although this was at first a setback, it provided an opportunity to learn more about how this species interacts with Asparagopsis and explore ways to control its spread and manage contamination.”
Dr Theobald’s work managing the contamination ultimately became one of several published studies arising from her doctorate, providing valuable knowledge for the emerging seaweed farming sector.
Native seaweeds with multiple environmental benefits
Beyond methane reduction, the seaweed farming industry may be able to provide other environmental benefits.
As seaweed grows, it absorbs nutrients such as nitrogen and phosphorus from seawater around it. In places like Queensland, where nutrient runoff from catchments can harm coastal ecosystems and the Great Barrier Reef, seaweed has the potential to improve local water quality while undertaking commercial farming.
Dr Theobald also contributed to research that narrowed more than 1,300 native seaweed species down to a shortlist of candidates with the greatest potential for cultivation in Queensland waters. The work identified species capable of improving water quality while producing products for agriculture and industry.
“The top performers were fast-growing native seaweeds that offered a balance of nutrient removal, ease of cultivation and commercial value,” she said.
“This work also highlighted that there’s still a lot we don’t know about Australian seaweeds and that there are many species with cultivation potential that require further research.”
Looking towards a sustainable future
CMERC Director and principal supervisor Professor Emma Jackson said the research delivered practical outcomes for the emerging sector.
“Emma’s work has addressed several critical barriers to cultivating Asparagopsis at scale,” Professor Jackson said.
“Her research provides the scientific foundation needed to support pilot-scale cultivation in Queensland and contributes to the development of a sustainable seaweed industry that could help reduce agricultural emissions and improve coastal water quality.”
Reflecting on her PhD journey, Dr Theobald said achieving her first published paper was one of her proudest accomplishments.
“It was so rewarding to be able to share my research on a larger scale,” she said.
“It’s exciting to think that the work I did during my PhD could help support the growth of Australia’s emerging seaweed industry and contribute to tackling real-world environmental challenges.”
Looking to the future, Dr Theobald believes Australia is still has much to learn about the potential of seaweed.
“Australia has an enormous opportunity to build a sustainable seaweed industry,” she said.
“While Asparagopsis has been the initial focus, I hope we’ll see exciting growth in edible seaweeds, bio-fertilisers, bio-products and many other applications over the coming years.”
Discover more research at CQUniversity's Coastal Marine Ecosystems Research Centre (CMERC).
