Could the Adelaide Desalination Plant be causing SA’s algal bloom crisis? Experts say no

A rapidly spreading social media theory blaming the Adelaide Desalination Plant for SA’s toxic algae crisis is right about just one thing, one expert says.

Thousands of South Australians are taking to social media to discuss a theory linking the state’s algal bloom crisis to increased production at the Adelaide Desalination Plant – but most experts say the plant is not to blame.

Punters have pointed out millions of fish and sea creatures across more than 200 species claimed by an algal bloom off the state’s coast since February coincided with the Adelaide Desalination Plant ramping up its production to full capacity for only the second time in its 13-year history.

A theory that the plant could be behind the crisis, in contrast to the explanation that the algal bloom has been caused by higher water temperatures, has taken off, with an SA Angler Magazine Facebook post about the topic on Wednesday attracting more than 500 comments.

The Adelaide Desalination Plant in Lonsdale, photographed on November 10, 2019. Picture: AAP/ Keryn Stevens

Dead sea life from algal blooms at Foul Bay, Yorke Peninsula. Picture: Stefan Andrews, courtesy of Great Southern Reef Foundation

Environmental microbiologist Chris Keneally, who studies the effects of hypersalinity on algae, said people were correct to link the timing of the desalination plant’s ramp-up and the algae outbreak – but they were related for a different reason.

“It’s not a coincidence,” he said. “(The increased production) started because we’re having a very dry summer and we need the water.

“The algal bloom is kicking off because of high sea surface temperatures, which is also causing the drought, those high temperatures.”

Dr Keneally said very salty conditions could help cause algal blooms in inland waters, but it was not possible from such a small output, especially where the output was in a far-away location in coastal waters.

He said the amount of salt pushed out by the plant was “like dropping a millilitre of something into an Olympic swimming pool” and for this “tiny, tiny amount” to cause a bloom the size of Kangaroo Island was “completely out of the question”.

Dead sea life from algal blooms at Foul Bay, Yorke Peninsula. Picture: Stefan Andrews, courtesy of Great Southern Reef Foundation

At a tour of the Adelaide Desalination Plant in 2015, plant manager Javier Artal and chairman Lew Owens near the Lime Clarifier. Picture: Mark Brake

The algae has spread along parts of the Fleurieu Peninsula and the southern coast of the Yorke Peninsula – a significant distance from the plant’s location at Lonsdale.

However, marine biologists Paul McShane and Ib Svane, who are opposed to the creation of a desalination plant at Port Lincoln, have argued there was no evidence to rule out the plant as a contributing factor.

While agreeing the algae had thrived in higher water temperatures, Prof McShane said strong jets used by the plant could disturb and mobilise sediments which harboured cysts of toxic algal species, which could release nutrients encouraging the algae to grow.

Some species of algae thrive in saltier conditions, but estuarine ecologist Faith Coleman said Karenia mikimotoi – the name of the algae killing marine life – preferred less salty water and did not thrive in salty water.

She said any effects on marine life from the plant would be within 100 metres of its discharge and these were monitored by the EPA.

A state government spokesman said ongoing monitoring confirmed no negative impact to the marine environment from the Adelaide Desalination Plant.

Originally published as Could the Adelaide Desalination Plant be causing SA’s algal bloom crisis? Experts say no