Serious concern as thick blanket of 'slick substance' appears off Aussie coast
The large, blue-green algae bloom off the coast of Mackay, Queensland has intensified scientists' fears over the destruction of the Great Barrier Reef.
A “slick substance” that recently emerged off the coast of a popular holiday destination has sparked fears of further destruction to Australia’s iconic Great Barrier Reef. The “thick blankets” of blue-green algae, also known as sea sawdust, appeared in Mackay in Queensland’s north over the past few weeks, turning the shoreline at some beaches a vivid pink and green.
Locals have posted images of the stunning sight online, while others told the ABC over the weekend they couldn’t help but notice the highly toxic bacteria’s pungent odour.
“It’s a bit hard to describe and has that bit of a pongy smell,” surfer Dwayne Close said.
When conditions are still, the algae — which is not considered to be harmful to humans but can cause skin irritation — rises from the bottom of the ocean floor and joins together in strings and clumps. While it is not uncommon in the area, the first bloom of the season has scientists concerned it could lead to a jump in the number of crown-of-thorns starfish (COTS).
The native predator that has up to 21 arms and hundreds of toxin-tipped thorns is one of the four main stresses on coral reefs for its ability to decimate coral tissue faster than it can grow.
Earlier this year, researchers revealed they had observed the starfish’s larvae feasting on the blue-green algae, otherwise known as trichodesmium, with the help of a microscope.
“Until now, not much has been known about sea sawdust as a food source, so we were certainly surprised to say the least,” marine scientist Dr Benjamin Mos told Yahoo News in July.
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Speaking to the ABC, Dr Mos said the starfish’s offspring use the algae to “fuel their development and growth”, prompting concerns about an increase in their population and the subsequent long-term impact on the Great Barrier Reef.
“We’re definitely concerned about outbreaks [of sea sawdust] as being another one of those impacts, which just adds to the negative impacts on colonies," Dr Mos said.
Researchers are now hoping to find larvae eating the algae in the wild to better understand and control major crown-of-thorns starfish outbreaks.
“If we can figure out how to reduce the impact of [crown-of-thorns starfish], we might give coral reefs a little more time,” Southern Cross University’s Professor Dworjanyn previously told Yahoo.
“We don’t yet know if sea sawdust blooms result in more adult [starfish] on coral reefs, so this research needs more work. However, our findings could be an important part of cracking that puzzle.”
In 2012, the Crown-of-thorns starfish control program was established to try and control outbreaks, with skilled divers able to kill more than 100 an hour by manually injecting them with salt or vinegar, Evan Quartermain, Head of Programs at Humane Society International, told Yahoo last year.
However, this approach has its limitations, he added, explaining that warming sea temperatures due to climate change can enhance the starfish’s larva.
“These mature crown-of-thorns can release 200 million eggs a year and be sexually mature within two years,” he said. “When the conditions are favouring them they can expand quite rapidly.”
