SYDNEY, Aug. 11 (Xinhua) -- Scientists in Australia have warned that methane-producing microbes in oxygenated coastal sands pose a significant, overlooked threat to climate goals by emitting one of the most potent greenhouse gases.
The finding could reshape understanding of ocean greenhouse gas emissions, overturning assumptions about marine methane formation, with "major implications for climate modelling and carbon accounting," a statement from Australia's Monash University said on Monday.
The study revealed that aerotolerant methanogens can thrive in dynamic coastal environments and produce methane by metabolizing compounds released from decaying seaweed and seagrass, even in the presence of oxygen.
Until now, scientists believed methane generation occurred only in oxygen-free environments, said Monash University Professor Perran Cook, the lead author of the study published in Nature Geoscience.
"This challenges a fundamental assumption in marine science...We've now shown that these microbes survive oxygen exposure with no ill effects," Cook said.
Working with the University of Southern Denmark, researchers surveyed Port Phillip Bay and Westernport Bay in the Australian state of Victoria, as well as sites in Denmark, isolating two new methanogen strains capable of rapid recovery and methane production following oxygen exposure.
"Our findings suggest that permeable sandy coasts, which make up half of the world's continental margins, may contribute far more to global methane emissions than previously thought," Cook said.
The study warns that decaying seaweed and seagrass drive methane emissions, undermining the narrative around "blue carbon" strategies, which promote coastal vegetation as a climate solution.
With warmer seas and rising nutrient pollution driving more algal blooms and biomass buildup on beaches, such conditions are likely to trigger more frequent and intense methane releases, Cook said. ■