HOT SPOT: Heron Island was the centre-point for scientists studying aerosols.
HOT SPOT: Heron Island was the centre-point for scientists studying aerosols. James Vodicka

Corals making cloud umbrellas to keep cool

IN PLACE of the usual alarming messages about the Great Barrier Reef, scientists have been able to announce some positive news.

New scientific research has found that corals are making themselves "cloud umbrellas" to stay cool.

A team of scientists, made up of researchers from Griffith University, Southern Cross University and the University of Southern Queensland, analysed 15 years worth of satellite-derived data from an area of about 100 by 100 kilometres centred around Heron Island, off Gladstone.

They found that corals are seemingly protecting themselves from stresses such as high water temperatures and high irradiance and the bleaching events related to them.

They do this by producing and releasing aerosols into the atmosphere to create an "umbrella of cloud cover" which helps cool them down.

Associate Professor Gabric from Griffith University has worked in marine aerosols for 25 years and said while the ability of phytoplankton to produce aerosols was well known, this research is the first time a connection has been made between the stresses corals are undergoing with the aerosols that have been detected above them in the atmosphere.

"Until recently, scientists didn't really appreciate that corals could produce these compounds that end up in the atmosphere and are converted through chemical reactions to aerosols," he said.

"What happens to these aerosols when they get into the atmosphere is that they reflect incoming solar radiation and can also modify cloud microphysics.

"They can make clouds brighter and they can make clouds hang around for longer, so it's sort of like creating a natural umbrella for the reef."

The data, field work and lab work revealed that if corals were under stress due to very strong irradiance (eg during periods of low tides) they protected themselves by releasing volatile compounds into the sea.

These compounds eventually become aerosols in the air above them, contributing to the formation of low-level clouds. And the implications of that are quite far reaching, according to Associate Professor Gabric. The research team's findings were published in the journal AMBIO.