Smoke The 2019-2020 bushfires in Australia caused phytoplankton blooms in the Southern Ocean to be greater than the entire Australian continent, according to new research.
An international team of scientists has discovered via satellite data that the proliferation of phytoplankton - microscopic marine algae - has occurred in the ocean between South America and New Zealand from October 2019 and lasted about four months.
Clouds of smoke from Australian black summer bushfires traveled to the stratosphere and it traveled the globe , depositing aerosol particles thousands of miles from Australia.
The study , published in the journal Nature , found the blooms were the result of iron particles in smoke aerosols.
Study co-author Professor Peter Strutton, of the Institute of Marine and Antarctic Studies at the University of Tasmania, compared the phytoplankton blooming up to "the whole of the Sahara Desert turning into a moderately productive prairie for a few months ".
Phytoplankton needs iron for photosynthesis. " The entire Southern Ocean is fundamentally low in iron because it is away from dust sources, so any small amount of iron that settles there can cause a strong response, "Strutton said.
Phytoplankton blooms are visible from space ad occur when sunlight and nutrients are plentiful, causing the population to explode. The massive bloom in the Southern Ocean has occurred at a time of year when phytoplankton activity is generally at its lowest.
Researchers estimate the amount of carbon absorbed by phytoplankton cells as The result of flowering was equivalent to around 95% of the emissions generated by the 2019-2020 bushfires.
In order for this carbon to be permanently removed from the atmosphere, however, the phytoplankton cells would have to sink into the depths of the ocean and be stored there, Strutton said.
"There is a lot of recycling of energy and biomass that occurs on the surface of the water. It is likely that a large partySome of this carbon that was initially absorbed may have been released into the atmosphere when these phytoplankton cells either started to decompose or were eaten. "
The team did not specifically examine the broader effects on the marine ecosystem of the large Southern Ocean bloom, but the moderate increase in activity phytoplankton over several months could also have impacted fish populations, Strutton said.
Professor Martina Doblin, director of the Institute of Science Sydney Marines at the Sydney University of Technology, which was not involved in the research, said the analysis conducted by ther his team during the fires confirmed that there were higher concentrations of another nutrient in the smoke from bushfires compared to normal air pollution.
" The nutrient content will come from the plant and soil that have been burnt. These nutrients, normally in a terrestrial system, have ended up in the ocean, "she said.
Preliminary data from her own research Doblin in estuaries are "aligned with this notion that aerosols can impact phytoplankton growth.
The results are presented in a separate study, also published in Nature , more precisely estimated the amount of carbon dioxide emitted by the 2019-2020 bushfire season.
Using satellite data, an international group of researchers discovered that the fires emitted 715 million tonnes of carbon dioxide between November 2019 and January 2020, exceeding the usual annual fire and fossil fuel emissions in Australia by 80%. A the previous estimate had put the number to approximately 830 million tonnes.