2020 Australian Wildfires Trigger Algal Blooms Thousands of Miles Away

Image: Japan Meteorological Agency via Wikimedia Commons

By Amy Lupica, ODP Daily Editor

Research has found that smoke and ash from Australia’s massive 2019 and 2020 wildfires triggered widespread algal blooms thousands of miles away. The Duke University-led study reported that the phenomenon could be effective in sequestering additional carbon, but algal blooms can also be toxic and devastating to wildlife and coastal communities. 


Why This Matters: Wildfires are becoming increasingly catastrophic, and are threatening carbon sinks from Siberia to South America. And experience has shown that wildfire smoke doesn’t stay put; it can have wide ranging health impacts and travel thousands of miles. For example, smoke from this summer’s Bootleg fire traveled 2,500 miles from Oregon to the East Coast.


Just as smoke travels across land, it can travel across waters and oceans, and it can alter both short and long-term water quality. Scientists have recorded wildfire smoke contributing to algal blooms for better and for worse, but as wildfires increase, so too will the chances of blooms, which is why experts are eager to find the good in them.


Smoke on the Water

This study is the first to link large-scale marine fertilization to pyrogenic iron aerosols from wildfires. Scientists concluded that these fire-borne particles provided nutrients to microscopic marine algae, which then bloomed en masse. Nicolas Cassar, a professor of biogeochemistry at Duke’s Nicholas School of the Environment, explained, “our results provide strong evidence that pyrogenic iron from wildfires can fertilize the oceans, potentially leading to a significant increase in carbon uptake by phytoplankton.”


Phytoplanktons are capable of absorbing large amounts of carbon, especially in large numbers. The research team found that the amount of carbon absorbed by these particular algal blooms may have temporarily offset the emissions created by the original fires. Still, it’s not yet known exactly how much carbon was absorbed, or if it remained sequestered for long. 


Algal blooms, however, can be fickle. Some are non-toxic, but others can produce neurotoxins that decimate wildlife populations and poison human water sources. Others can consume all of the oxygen in an environment, creating a hypoxic dead zone where almost no life can survive. Still, researchers say that these findings present an opportunity to learn more about the impacts of climate change and carbon sequestration. Weiyi Tang, a postdoctoral fellow in geosciences at Princeton University and co-leader of the study, said, “These fires represent an unexpected and previously under-documented impact of climate change on the marine environment, with potential feedbacks on our global climate.”

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