How South Australia's Algal Bloom Is Threatening Marine Life and Public Health

Dead and dying polychaete worms at the southern end of Coorong’s North Lagoon. Photograph: Glen Hill (The Guardian)

Toxic Algal Bloom Threatens South Australia's Coastline
A major concern for South Australians as toxic agal bloom Karenia mikimotoi, which has been on the rise, affecting the coastlines of the state since March. Environment Institute member Professor Justin Brookes recently spoke with ABC National Radio, to share why this is concerning and what may have caused it.  

Coorong is a vulnerable area located at the bottom of the River Muarry. It stretches about 120km and features a sheltered lagoon home to various organisms, including unique birds from Siberia, Japan and China, a commercial fishery, an important tourism area, and an adjacent surf coast.

Many marine animals have been found dead. In the northen part of the Coorong Lagoon,curcial sources of food such as estuarine snails, shore crabs, baby flounder and polychaete worms have been spotted washed up on shores. Until June 24, the algae had not reached mainstream beaches. However, the public recently found large numbers of dead fish, rays, and unsual marine life on the shores of Grange Jetty, all the way down to Christies Beach surf club.

The area has faced many years of challenges, particularly the Millenium Drought. The Coorong, Lower Lakes and Murray Mounth (CLLMM) Recovery project helped to restore and save Coorong, with environmental water returning to the river. This also led to the return of the Murray cod, helping to restore the Murray-Darling Basin.

Expert Perspectives and Government Response
While the weather cools down, it may help the algal blooms to dissipate, explains Professor Brookes. “We have these toxic blooms [that] come and go both in freshwater systems and marine systems, and there [are] a few ingredients they need to grow”.

Dr Susan Close, South Australia’s Environment Minister, said, “The algal bloom is a dynamic situation. It’s movements depends on weather and water conditions, and [that] makes the effect on people and wildlife unpredictable.”

With our most recent storms this week, the state government hoped they would help break down the bloom. In fact, they’ve done the opposite - the storms have spread the algae into new waterways.

The major concern ahead is the algae making its way into urban area waterways. Most recently West Lakes tested positive for the bloom, and the Port River remains an area of concern, as both areas are popular recreational fishing sites.

Just this week, the Department for Environment and Water (DEW) SA annouced that the algal bloom has been detected in the Port River. State government agencies are conducting weekly water samples across 17 sites. The Port River holds the Adelaide Dolphin Sanctuary, where water is closely monitored by National Parks and Wildlife Services.

Further testing in the Coorong North Lagoon confirmed the Kareina between Seven Mile Basin and Long Point. Weekly testing is also underway to track the algal bloom’s movement.  It is unclear how long this will last, as some blooms across the globe have lasted from one week to several months, depending on wind, rain, and ocean tempreatures.

Currently DEW, the Environment Protection Authority (EPA), the Department of Primary Industries and Regions (PIRSA) and SA Health are observing the condition of the bloom.

Public Safety, Health Impacts, and Scientific Insight
Physical signs are present at affected beaches and parks to ensure community safety community, warning dog owners to be mindful. The public is advised to not to swim in contaminated water where it’s discoloured and foaming, or where the dead marine life is present, and importantly, not to touch it.

Professor Dominic McAfee, Future Making Fellow at the Environment Institute also spoke with ABC National Radio yesterday morning . He said SA Health has suggested that the bloom isn’t harmful. However, he and his colleagues have faced physical discomfort, sore eyes or throats, and have felt sick for up to 24 hours after being in the water “It's important that we get eyes under the water, because what we're seeing on the surface and on our beaches is likely just the tip of the iceberg,” he said.

Professor McAfee said “Everyone's talking about it, and it's nice [that] the marine environment getting all this attention, but the backdrop is this real disaster, which has us all feeling a little bit helpless.” he expresses.

Professor McAfee visited one of the affected areas the other day, north of Grange Beach. He described what he saw: “It hits quite hard when you’re on the beach, and you can also see and smell the foam.”

Understanding the Algae’s Role and Risks
Professor Brookes describes the algae’s growth as almost competitive. “There [are] lots of different species of algae we have, and some rise up to dominance. We tend to see a succession - some will rise up and then others will take over,”

Agal bloom is just like any plant, they need nutrients, particulary nitrogen phosorus, Professor Brookes points out, and they thrive in warm tempreatures. “The warmer the temperature, the faster [it] grows. But they also need this inoculum - cells there that are going to start the population”.

Now, as to why and how the toxic bloom has alarmingly spread so fast, he, along with other experts, says, “We're not really sure why this particular algae has chosen this moment to come along. It's sort of colonised right across the coastline. But it is a problem species because it's toxic, and it's probably not a great food source either.”

The algae are often viewed as problematic, Professor Brookes points out. However, he strongly emphasised that the algae drive essentially everything within the marine environments.

“About one-third of the oxygen that's in the atmosphere has been produced by algae. [They] take on that carbon dioxide, they produce oxygen, and they’re a food source,” he explains.

“They're capturing carbon, so all the carbon that we see finding its way up into our largest predators - you know the whales or the sharks - all of that carbon has come through algae, into the food web, and up and into those organisms.” Professor Brookes notes out that while this algae is “a bit problematic,” algae as a whole are essential.

Socio-Economic Fallout and The Need for Action
Swimmers and surfers have been warned to stay clear of the waters. As Professor Brookes describes it “This is a significant, indiscriminate bloom that seems to be attacking all organisms.”

Algal blooms need light, they’re like plants. “They photosynthesise, they’ve got pigments, they take in light and grow,” Brookes says. “They need nutrients, warm temperatures, and a starting presence of cells in the water column, then they can start to grow.”

Understanding South Australia’s current position with the toxic blooms also acknowledging the broader socio-economic implications, not just on the environmental ones. Shellfish fisheries have been forced to close, including oyser farms in affected areas.

Professor McAfee ensures that there is constant monitoring of farmed stock. “We need to have mechanisms in place to support industries as well as the environment to manage them. That's where the government natural disaster response is kicking in.”

As for future measures, Professor McAfee stresses, “We are looking at something like an underwater bushfire, and I'd like to see a response that's that's akin to to how we respond to bushfires on land”. This comparison the scale of disaster. “There's not a lot we can do about this algal bloo, but we do need to be prepared for the possibility of many more like this in the future”.

Conservation action is required. Professor McAfee recommends that we must let nature runs its course, while monitoring and collecting data to inform future evidence-based solutions making proactive and informed decisions to respond to catastraphoic events, ensuring we can protect all those affected.