SYDNEY, Sept. 16 (Xinhua) -- Researchers said smoke from Australia's 2019 to 2020 bushfire season triggered a massive phytoplankton bloom in the ocean between South America and New Zealand.
The study was published in the Nature journal on Wednesday, and lead researcher Peter Strutton from the University of Tasmania said they found the links between the phytoplankton bloom and the smoke triggered by the bushfires.
In the summer beginning in 2019, the Australian state of New South Wales experienced bushfires of unprecedented extent and intensity.
The fires burnt through an estimated 5.3 million hectares or 6.7 percent of the state's total land area, realizing an estimated 715 million tonnes of carbon dioxide (CO2) into the atmosphere -- more than Australia's total annual emissions.
Using satellite imagery, the researchers observed the smoke cover vast distances through the earth's stratosphere before settling above the Southern Ocean thousands of kilometers off Australia's east coast.
"The phytoplankton bloom in this region was unprecedented in the 22-year satellite record and lasted for around four months," said Strutton.
The bloom was shown to spread across an area of the ocean larger than the entire Australian continent.
"What made it more extraordinary is that the part of the season when the bloom appeared is usually the seasonal low point in phytoplankton, but the smoke from the Australian bushfires completely reversed that," said the researcher.
One of the seemingly positive consequences of rapid growth of the microscopic marine algae, phytoplankton, is its natural process that absorbs CO2.
While it is estimated that the huge levels of absorption were enough to offset the CO2 released in the fires, Strutton warned that conclusions should not be jumped to in terms of the phenomenon's greater implications.
"We need a far more comprehensive representation of wildfires in climate models and targeted studies to understand their influence on marine ecosystems. Our capacity to adapt to future climate change depends on it."
Strutton said further research would be needed to determine if the sequestered CO2 is released back into the atmosphere or stored deep in the ocean after the event passes.
Weighing in on the subject, international expert Dr. Chris Mays from the Department of Palaeobiology at the Swedish Museum of Natural History, lauded the importance of linking algal blooms to wildfires but warned of its impact on marine ecosystems.
"Explosive blooms of plankton can be deadly to animals. A single bloom event can wipe out countless thousands of animals in a few days, and leave 'dead zones' in freshwater lakes and coastal areas," he said.
He said that human activity is making such events more frequent and devastating.
"For these kinds of toxic soup, you need three main ingredients: high temperatures, high CO2 and an influx of nutrients ... Humans have been providing two of these in abundance." Enditem
