World Microbiome Day is an opportunity to celebrate the microscopic organisms that underpin life on Earth, including the vast communities of microbes that help keep our oceans healthy and productive.
Across Australia, the IMOS National Reference Stations provide long-term observations of marine microbial communities, helping scientists understand how these microscopic organisms vary between regions and over time.
Research using IMOS data has shown that microbial communities differ significantly from tropical waters in northern Australia to the cool temperate waters of Tasmania. In temperate regions, microbial communities are generally more diverse and experience stronger seasonal changes, supported by higher nutrient availability and ocean mixing. In contrast, tropical waters are typically dominated by smaller microbes adapted to stable, low-nutrient conditions.
These differences influence how energy and carbon move through marine food webs and play an important role in supporting ecosystem productivity.
Marine microbes are also highly responsive to environmental change. Shifts in sea temperature, nutrient availability and other ocean conditions can rapidly alter the composition and function of microbial communities.
Studies using IMOS observations have shown that marine heatwaves can temporarily transform southern microbial communities, making them resemble those typically found in tropical waters.
Understanding how microbial communities respond to environmental change is essential for predicting the future health and resilience of Australia’s marine ecosystems in a changing climate.
References
Brown, M.V. et al. (2018) – Regional patterns in Australian marine microbial communities.
Brown, M.V. et al. (2024) – Marine heatwaves drive shifts in Australian ocean microbial communities.
Header image: Miles Noel