Scientists in Tasmania are mapping local variations of the red Asparagopsis seaweed to identify the best genetics for methane-reducing livestock feeds.
Associate Professor Jeff Wright, at the University of Tasmania’s Institute of Marine and Antarctic Studies, is leading research to look at the distribution, abundance and chemical variation of the subtropical Asparagopsis armata species around Tasmania.
The results will support the state's emerging seaweed farming sector, led by Sea Forest, based at Triabunna on the east coast. Sea Forest is currently the only Tasmanian company producing Asparaposis, which it uses as a feed supplement to help reduce livestock methane production in the agricultural sector.
Methane production from farmed livestock is a significant contributor to global greenhouse gas emissions. Asparagopsis is a potential solution to this issue as it produces bioactive compounds that, when fed in small amounts to cattle and sheep, can reduce methane emissions by 90% and up to 98% in some Sea Forest trials.
This has generated significant interest in commercial livestock feeds, to help mitigate greenhouse gas production and limit climate change impacts. In recognition of this potential, Sea Forest was a finalist in the ‘Fix our climate’ category of the Prince of Wales’ 2023 Earthshot Prize.
Dr Wright says the IMAS team is collecting data that will allow Sea Forest to identify and target sites with high-quality Asparagopsis that can be used as seed stock for cultivation at either its Triabunna or Swansea farms.
“This research will also determine whether different genetic strains exist in Tasmania and whether these strains have different bioactive potential,” he says.
“Bioactives are natural compounds that Asparagopsis produces to fight bacteria in the ocean, but these compounds also inhibit the bacteria that produce methane in the rumen of cows and sheep. The inhibition of these bacteria reduces methane emissions.”
While Asparagopsis is native to Tasmania, basic information on where it grows, its seasonal patterns of abundance, reproduction and bioactive compounds, and whether there are genetically different strains is limited.
“The overall aim of this project is to address these knowledge gaps,” says Dr Wright.
Diving for answers
The IMAS field research team is sampling and comparing bioregional and seasonal variations of Asparagopsis at 15 sites across five Tasmanian regions over a 12-month period.
Underwater towed video cameras, photographs and diver surveys are being combined to map Asparagopsis distribution and abundance.
Seaweed samples collected are being analysed for the bioactive compounds that cause methane reduction. “We’ll also use these samples for analysing Asparagopsis genetics and reproduction,” adds Dr Wright.
Researchers have completed the first sampling period, with sites in the D’Entrecasteaux Channel, Port Arthur, Coles Bay, the Furneaux Group and north coast all surveyed. The final sampling period will be between February and April next year, with the project to wrap up around July 2024.
The information gathered in this project will also assist the Department of Natural Resources and Environment Tasmania in managing the collection of Asparagopsis seedstock for propagation of the species.
Funding for the project has come from the Marine Bioproducts Cooperative Research Centre, the Department of Natural Resources and Environment Tasmania, Sea Forest Ltd and the University of Tasmania (UTAS).