When the seat hurts, we hurt’: Marine losses hit hard

For Traditional Owners of SA’s coastline, and those most connected to the ocean, the emotional and mental toll of the state’s algal bloom has hit hard. Now experts are racing to assess the ecological impacts and develop strategies to prevent future outbreaks. Here’s what can be done to help.

Since March, the toxic algal bloom in South Australia has wreaked havoc on the state’s marine life, but the devastation runs deeper than many might think.

“For Traditional Owners of the South Australian coastline, our connection to the marine environment is both cultural and spiritual,” says Brad Darkson, Narungga, Director of Moonrise Seaweed Co., and Flinders University PhD candidate. 

“When we witness major die off events due to external stressors (like agricultural runoff and rising sea temperatures) our elders and Community feel both distress and outrage that this has been allowed to occur.”

Coastal communities have also been hit hard by the disaster, the scale of which has never been seen before.

Tom, a south coast resident and local surfer, is just one of the state’s residents who experienced the effects of the algal bloom first-hand.

“I was tight chested, and from there I had really sore, irritated, red eyes – it felt like a sinus and throat infection, but it came on really fast,” he explains.

Tom had been surfing in May at Waitpinga Beach, located on the Fleurieu Peninsula. Whilst he recovered quickly from his symptoms, he says those in the beachside communities have been deeply concerned about what they’ve been witnessing.

“It is a worry especially when we’re looking at such fragile ecosystems like leafy seadragons and such, species that are already in trouble - it’s not good.” 

As the algal bloom continues, there have been calls for a Royal Commission into the catastrophe, as well as for it to be declared a national disaster. 

Flinders’ Dr Georgina Wood says it is critical that this is recognised as a crucial event and that significant national and state investment is needed.

“This is one of the most significant marine mortality events on the great southern reef in living memory,” says Dr Wood, who also holds a position at the University of Western Australia.

“The algal bloom has had a devastating impact on local marine life, and it will take a long time for both ecosystems and industry to recover.”

Fortunately, South Australia's leading experts in this field are working together to better understand this deadly algal bloom. By combining their knowledge and resources, they’re working to uncover the causes behind this environmental event and develop strategies to prevent it or quickly put a stop to a future outbreak.                           

When algae turns deadly: The science behind the devastation

Algal blooms are a natural phenomenon which involve the rapid increase of algae populations – many of which aren’t harmful.

Darkson, who is developing accessible methods for cultivating seaweed to remediate coastal waterways, based on First Nations knowledge systems, says algae contributes a significant portion of the oxygen in our atmosphere and marine animals depend on productive algal blooms to form the basis of their food chains.

In this case, the bloom, made up of Karenia mikimotoi amongst other potentially harmful algae species, was caused by warmer-than-normal sea temperatures and high-pressure systems leading to still conditions where the algae could flourish. The longer it has hung around, the more damage it has done. High nutrient levels from recent extreme events might have also contributed to this perfect storm, where all the conditions are aligned for strong algal blooms.

Dr Wood says the algal bloom is likely to reoccur given the increasing frequency of some of the likely contributors such as hot, calm waters and increased nutrients.

So how can we, if at all, prevent it from happening again, or at least lessen the impact?

The answers we need to prepare for the future

Professor Charlie Huveneers, Director of Flinders University Marine and Coastal Research Consortium, who also leads the Southern Shark Ecology Group (SSEG), and his team, have collected dead sharks and rays, to better understand how the algal bloom affects marine organisms and why some species seem more impacted than others.

The team, supported by Green Adelaie and IMOS, also has an extensive array of acoustic receivers along the metropolitan beaches and have tagged many sharks and rays like southern fiddler rays and Port Jackson sharks. 

"Thanks to this existing dataset, we will be able to compare the movement, residency, and survival of these species during the algal bloom to previous years under normal conditions,” Professor Huveneers says.

“This will provide us with a better understanding of the impacts of the algal bloom.”

Professor Elizabeth Dinsdale and her team have been looking at microalgae and the marine bacteria and viruses present in it during this algal bloom. Normally microbes and viruses in the marine environment provide benefits, such as nutrients and oxygen that we breathe.

“We now have the dataset to describe how many bacteria and viruses are associated with the microalgae,” says Professor Dinsdale, who works with the Flinders Accelerator for Microbiome Exploration (FAME).

“What we’ve been seeing is that where the microalgae are growing rapidly the abundance of microbes are also increasing.

“The high growth of bacteria uses oxygen causing conditions where there is a complete absence of oxygen in the water which affects the health of organisms such as sharks, rays and fish.”

Professor Dinsdale says they are working on finding a bacteria or virus that may infect the micro-algae and control its growth.

Darkson says the spiritual and mental health impacts for Community should not be overlooked as we come up with strategies to deal with future reoccurrence. 

“We need to start implementing both local and global solutions to mitigate against these events recurring.”

Dr Wood has been working in collaboration with the Great Southern Reef Foundation, and Professor Dinsdale, to survey reef life in affected areas. The team have been collecting water samples to learn how microbes in the water impact marine life once this toxic algal bloom subsides.

"This is a dire reminder of how vulnerable our marine ecosystems are and how we need significant investment to better understand our reefs and broader underwater ecosystems,” Dr Wood says.

"The Great Southern Reef Research Partnership has called on the government for $40 million dollars over 10 years for a national Great Southern Reef monitoring program – it's critical to gather information on the state of our marine biodiversity now as we face further impacts in the face of rapid environmental change.”