Tas marine ecologist weighs in on Tassie’s risk of algal bloom

The very same microscopic threat currently ravaging South Australian waters already lurks in Tasmanian waters. A Tassie expert warns our island state is could be one ‘perfect storm’ away from marine devastation.

Claris shipwreck post-algal bloom. Picture: Mark Tozer / Supplied

As the South Australian and federal government urgently looks to contain the mass algal bloom off the SA coastline, a Tasmanian marine ecologist has weighed in on Tassie’s chances of its own algae increase and warns that we could only be one perfect storm away from coastal devastation.

It’s been four months since the toxic algal bloom began near Adelaide and spread along thousands of kilometres of SA coastline, killing sharks, rays, fish, dolphins and seals as well as wiping out vulnerable ecosystems like reefs and seagrass forests.

Both the state government and Australian Government will contribute $14m to the research and clean-up of the bloom, with the SA Premier Peter Malinauskas declaring the event a “natural disaster”.

Federal Environment Minister Murray Watt and Boothby MP Louise Miller-Frost at North Glenelg inspecting dead marine life. Picture: Tim Joy

For University of Tasmania’s Institute of Marine and Antarctic Studies (IMAS) senior researcher and marine ecologist Dr Scott Bennett, the potential for the same algal bloom to spread to Tasmanian waters is a ‘yes and no’ answer.

“The SA algal boom is made up mainly of the algae species Karenia mikimotoi, which is already present in Tasmanian waters,” he said.

“However, the bloom won’t be carried down on ocean currents or washed down to us.

“It’s more a question of whether Tasmania could have the same conditions to bring about an algal bloom like that in SA.”

Dr Scott Bennett from the Great Southern Reef Foundation. Picture: Stefan Andrews

Dr Bennett said factors of the SA algal bloom, including a marine heatwave and warm winds, plus a plume of nutrients making their way into the ocean, have led to high concentrations of algae and the algal bloom taking nutrients available in the water away from other marine life.

“While we [Tasmania] haven’t seen anything of this scale, we have had blooms that impacted our marine environment,” he said.

“We’re seeing more and more heatwaves in Tasmania as well, with the frequency and intensity growing – heatwaves are a new normal.

“These warmer conditions in the water promote the growth of algae and support big populations or ‘blooms’.

“The only way we can deal with that is cutting out carbon emissions, which is a long game fix, but we can’t ignore it.”

Short-tailed stingray killed in the algal bloom. Picture: Kathryn Lewis

Dr Bennett said ensuring nutrient pollution – such as that from agricultural land run-off and run-off leaching into water catchments – doesn’t make its way into our oceans, as well as looking after cultural ecosystems like kelp forests and wetlands, would minimise Tasmania’s vulnerability to algal blooms.

“We are definitely susceptible to an algal bloom, but how severe and how far it goes depends on the steps we put in place to prevent it,” he said.

“It protects industry, our way of life, so these are crucial changes to be addressing now, before a catastrophic bloom happens.”