Surprise fix for toxic algal bloom in South Australia

Restoring native oyster reefs along South Australia’s coastline could be key to tackling the state’s toxic algal bloom crisis.

Simply put, “oysters eat algae,” said Manny Katz, director of the Eyre Lab, a science project that aims to revitalize oyster reefs destroyed by European settlers in early colonial times.

“They’re sucking it up, they’re processing it,” Mr. Katz told NewsWire.

He says we need to stop thinking of oysters like animals because they behave more like forests. Because the most important function of oysters is to filter water.

“A single oyster can filter about 200 liters of water a day,” he said.

“If we multiply that by billions and billions of oysters, you would have a really healthy oyster. [and] “clean water,” he said.

Oyster reefs covered approximately 1,500 kilometers of South Australia’s coastline. Less than 1 percent of these ecosystems survive today, as early settlers destroyed the reefs in their efforts to gather food and even make building materials.

In fact, Australia’s entire coastline has suffered a “tremendous loss” of oyster reefs after almost a century of dredging of habitats needed to keep ocean water clean.

Mr Katz, along with University of Adelaide researcher Dominic McAfee, embarked on a project to create artificial oyster reefs before devastating toxic eruptions. Now, their project is supported by some of the funds from the $102 million Summer Algal Plan.

“What we are doing is an underwater reforestation project.” Mr. Katz said.

“We can regrow native oysters across the sea…we are rebuilding the foundations on which oysters can settle.”

When Mr Katz first came into contact with the algal bloom, he was “devastated” after seeing horrific images of dead fish washing up on the beach.

As a diver and someone who goes underwater to investigate these areas, he says the situation is even worse underwater.

“It looks apocalyptic. Like that’s the only way to describe it,” he said.

“For every fish you saw on the beach, there were hundreds or even thousands of dead fish underwater.”

While harmful algae produce toxins that kill and pollute marine life, the program’s director says he is “optimistic” about the project’s positive effects, which will help provide a filter in the ocean, but warns that its efforts are aimed solely at habitat destruction.

“If we want this algal bloom to stop, we need to figure out how to deal with pollution… rising ocean temperatures, marine heat waves… climate change.”

“I’m optimistic, there’s a lot of work to be done,” he said.

“It won’t happen overnight, it will take years.”