
Melaleuca wetland forests in New South Wales, Australia, are hotspots for tree microbial life
Luke Jeffrey / Southern Cross University
The biodiversity of tree bark has long been overlooked, but recent research sheds light on the vast microbial communities that inhabit this unique habitat and their potential role in mitigating greenhouse gases in the atmosphere.
Scientists have discovered that a single square metre of tree bark can host trillions of bacteria, comparable to the microbial populations found in soil. This microbial ecosystem, known as the caulosphere, is a crucial but understudied component of forest ecology.
Research led by Bob Leung at Monash University in Australia focused on the paperbark tree species Melaleuca quinquenervia, revealing a diverse community of over 6 trillion bacteria per square metre of bark. Genetic analysis identified novel bacterial families capable of utilizing hydrogen, carbon monoxide, and methane as energy sources, potentially influencing greenhouse gas dynamics.
Further investigations on various Australian tree species demonstrated that bark microbes play a dual role in greenhouse gas exchange, consuming gases like hydrogen, carbon monoxide, and methane under aerobic conditions while producing these gases in anaerobic environments such as wetlands.
The global impact of bark microbial activity on atmospheric hydrogen cycling is estimated to be significant, potentially contributing up to 2% of total hydrogen removal. This newfound understanding of tree bark’s role in greenhouse gas regulation highlights the need for broader studies across diverse forest ecosystems and climatic regions.
According to Luke Jeffrey from Southern Cross University, the discovery of trees actively influencing atmospheric methane levels presents an exciting opportunity for climate change mitigation strategies. Understanding the complex interactions between bark microbes, fungi, and surrounding environments will be crucial for unlocking the full potential of trees in addressing greenhouse gas emissions.
While the study underscores the importance of tree bark microbiomes in global biogeochemical cycles, further research is needed to unravel the full extent of their impact and diversity across different tree species and ecosystems.
Brett Summerell from the Botanic Gardens of Sydney emphasizes the need for continued exploration into the microbial communities of tree bark, particularly in arid regions like savannahs and woodlands. By elucidating the intricate relationships between fungi, bacteria, and tree bark, scientists can enhance our understanding of ecosystem dynamics and climate change resilience.
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