Corangamite Shire blasting blue-green algae on Lake Bullen Merri with ultrasonic waves

A test using solar-powered ultrasonic waves to blast green slime might sound like something out of a sci-fi movie, but it’s happening right now in South West Victoria.

The western district’s volcanic lakes look tempting for a summer swim, but are often inaccessible due to blooms of toxic blue-green algae.

Lake Bullen Merri, near Camperdown, has been filled with seaweed mud for years, but the local council is hoping a trial using ultrasonic sound waves in the water will solve the problem.

Corangamite Shire environmental manager Lyall Bond said the solar-powered equipment was on four floating pontoons anchored in the lake.

Toxic blue-green algae have infested Lake Bullen Merri near Camperdown. (Provided: Camperdown Angling Club)

“We normally see when blue-green algae die. They form this thick, paint-like layer that sits on the surface,” he said.

“The science behind this is that basically these sound waves will damage the air sacs in algae that regulate the height of algae in the water column.

“Because they can’t move up and down with sunlight, algae die much faster.”

The method has been used around the world and had mixed success, Mr Bond said.

Two scuba divers in murky green water
The water is popular among lake-goers, but flowers often make it inaccessible.(Provided: PADI)

Hope to expand the project

As its 12-month trial draws to a close, the council hoped Victoria’s Department of Environment, Lands, Water and Planning (DELWP) would provide the $1.5 million needed to install 16 floating solar devices and monitor algae.

Blue-green algae in the lake
The council hopes DELWP will provide continued funding to control the algae.(Provided: Camperdown Angling Club)

“This trial has shown it has an impact on algae. Now we are pushing for continued investment,” Mr Bond said.

But he warned that this would not result in the complete eradication of algae from the lake.

“These ultrasonic devices really only treat the symptoms… they don’t actually fix the nutrients that are in the lake or any of these issues,” Mr Bond said.

“So from a longer term perspective, we will continue to have algae and there will be problems.”

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