Toxic algae are turning South Australia's coral reefs into underwater graveyards – and there's no end in sight
The long saltwater clams, resembling old-fashioned razors, normally burrow into sand to avoid predators. But when Bennett, an ecologist, visited South Australia's Great Southern Reef last month, he saw thousands of them rotting on the sea floor.
'100% of them were dead and wasting away on the bottom,' Bennett told CNN.
Since March, a harmful algal bloom, fueled by a marine heat wave, has been choking South Australia's coastline, turning once-colorful ecosystems filled with thriving marine life into underwater graveyards.
The bloom has killed about 15,000 animals from over 450 species, according to observations on the citizen science site iNaturalist. They include longfinned worm eels, surf crabs, warty prowfish, leafy seadragons, hairy mussels and common bottlenose dolphins.
The algae have poisoned more than 4,500 square kilometers (1,737 square miles) of the state's waters – an area larger than Rhode Island – littering beaches with carcasses and ravaging an area known for its diversity.
It's 'one of the worst marine disasters in living memory,' according to a report by the Biodiversity Council, an independent expert group founded by 11 Australian universities.
The toxic algal bloom has devastated South Australia's fishing industry and repelled beachgoers, serving as a stark warning of what happens when climate change goes unchecked.
Once a bloom begins, there is no way of stopping it.
'This shouldn't be treated as an isolated event,' Bennett said. 'This is symptomatic of climate driven impacts that we're seeing across Australia due to climate change.'
It all started back in March, when dozens of surfers at beaches outside Gulf St Vincent, about an hour south of state capital Adelaide, reported experiencing a sore throat, dry cough and blurred vision after emerging from the sea.
Shortly after, a mysterious yellow foam appeared in the surf. Then, dead marine animals started washing up.
Scientists at the University of Technology Sydney soon confirmed the culprit: a buildup of a tiny planktonic algae called Karenia mikimotoi. And it was spreading.
In early May, the government of Kangaroo Island, a popular eco-tourism destination, said the algal bloom had reached its coastline. A storm at the end of May pushed the algae down the coast into the Coorong lagoon. By July, it had reached the beaches of Adelaide.
Diverse algae are essential to healthy marine ecosystems, converting carbon dioxide into oxygen and benefiting organisms all the way up the food chain, from sea sponges and crabs to whales.
But too much of one specific type of algae can be toxic, causing a harmful algal bloom, also sometimes known as a red tide.
While Karenia mikimotoi does not cause long-term harm to humans, it can damage the gills of fish and shellfish, preventing them from breathing. Algal blooms can also cause discoloration in the water and block sunlight from coming in, harming ecosystems.
The Great Southern Reef is a haven for 'really unique' biodiversity, said Bennett, a researcher at the University of Tasmania, who coined the name for the interconnected reef system which spans Australia's south coast.
About 70% of the species that live there are endemic to the area, he said, meaning they are found nowhere else in the world.
'For these species, once they're gone, they're gone.'
Nathan Eatts hasn't caught a single squid since April.
On a good day, Eatts could catch 100 in the waters where he's fished commercially for 15 years off South Australia's Fleurieu Peninsula.
Since the harmful algal bloom began, his business, Cape Calamari, has gone 'pretty much down to zero,' Eatts said.
While more mobile fish can move to cleaner waters during an algal bloom, invertebrates like shellfish and sea stars, and other species associated with the reef, are suffocated by toxic algae.
'We don't know whether they've all died, or they're just seeking refuge in deeper water, waiting for it all to clear,' he said.
Many fishers have lost their livelihoods overnight, with about a third of the state waters completely devoid of fish, according to Pat Tripodi, the executive officer of the Marine Fishers Association, which represents the interests of most commercial fishing license holders in the state.
'Wherever the algal bloom hits, there is zero life,' Tripodi said.
'It's a really high emotional and mental strain on these individuals, because many of them don't know how or if they will ever recover from it.'
Beyond the fishers themselves, the bloom is having a knock-on effect on the state's seafood industry, which is valued at almost 480 million Australian dollars ($315 million).
Seafood processors, transport companies, grocers and restaurants are all feeling the pain, Tripodi said.
Eatts comes from a long line of fishers, and they've never seen anything like this.
The last time a harmful agal bloom swept South Australia was in 2014, but it was much more localized.
Toxic algal blooms are naturally occurring and are common around the world, including in the US. But climate change is making them more frequent and more severe.
The foundation for the South Australian bloom was laid back in 2022, experts believe, when catastrophic flooding swept the Murray, Australia's longest river, washing extra nutrients into the Southern Ocean.
The next summer, currents brought nutrient-rich water to the surface in a process called cold water upwelling.
Then, a marine heatwave in September 2024 caused ocean temperatures to be about 2.5 degrees Celsius warmer than usual. That, combined with calm water conditions and light wind created conditions for the algae to grow and spread.
There is no way for humans to stop a harmful algal bloom – its trajectory largely depends on natural factors like wind and weather patterns.
Peter Malinauskas, South Australia's premier, told public broadcaster the ABC on Tuesday that the crisis is a 'natural disaster, but it's different to ones that we're familiar with in Australia.'
'With a bushfire, you can put the fire out. If there's a flood, you can do the modeling to have a sense of where the water is going to go, whereas this is so entirely unprecedented. We don't really know how it's going to play out over coming weeks and months ahead.'
This week, Prime Minister Anthony Albanese's government announced a support package of 14 million Australian dollars ($9.2 million), which has been matched by the state, to help with the cleanup and economic fallout from the ecological crisis.
But Canberra stopped short of calling it a natural disaster, a declaration which would have unlocked additional funding.
As extreme heat events become more common around the world, Bennett said the government needs to do more to prevent and protect against future algal blooms – first and foremost by cutting carbon emissions.
Marine ecosystems can be 'resilient,' Bennett said. But he added that Australia must protect habitats, such as kelp forests, seagrass meadows, and oyster reefs, which absorb excess nutrients and keep the oceans healthy.
Eatts, the calamari fisher, said it 'hits home hard' to see South Australia's natural beauty spoiled by this crisis. The other day, he saw a dead dolphin on his local beach.
'You take it for granted where you live and what you see on a daily basis,' he said.
'But it takes one event of nature like this to come through, and it breaks your heart watching it unfold.'
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
WIRED
16 minutes ago
- WIRED
Scientists Say New Government Climate Report Twists Their Work
Jul 30, 2025 4:31 PM A new Department of Energy report 'fundamentally misrepresents' climate research and leaves out key context, multiple scientists cited in the report tell WIRED. Emissions fume at the coal-fueled Oak Grove Power Plant in Robertson County, Texas. Photograph:All products featured on WIRED are independently selected by our editors. However, we may receive compensation from retailers and/or from purchases of products through these links. A new report released yesterday by the Department of Energy purports to provide 'a critical assessment of the conventional narrative on climate change.' But nine scientists across several different disciplines told WIRED that the report mishandled citations of their work: by cherrypicking data, misrepresenting findings, drawing erroneous conclusions, or leaving out relevant context. This report was introduced on the same day that the EPA announced it would seek to roll back the endangerment finding, a crucial 2009 ruling that provides the scientific and legal basis for the agency to regulate greenhouse gasses under the Clean Air Act. In its draft reconsideration of the finding, the EPA cites the paper from the DOE as part of a review of 'the most recently available science' that it undertook to challenge the validity of the 2009 ruling. 'The goal is to restore confidence in science, in data, in rationalism. That's what enabled the creation of modern science,' DOE Secretary Chris Wright said in an Fox interview Tuesday with EPA Administrator Lee Zeldin, to celebrate what Zeldin called 'the largest deregulatory action in the history of the United States.' 'We slid back into sort of a cancel culture, Orwellian squelching of science in talking about 'the' science, as opposed to the process that is science,' Wright continued. 'We need to restore some common sense around climate change and energy.' The report was authored by four scientists and one economist who are familiar contrarians in the climate science world. Three of the report's authors were recently hired at the Energy Department, the New York Times reported earlier this month, prompting alarm among mainstream scientists who have long followed their work. Each author has a long history of producing work that challenges mainstream consensus on climate science. Their work is often promoted by interests seeking to discredit scientific findings or downplay climate action. The DOE report's summary states that it finds '[CO 2 ]-induced warming appears to be less damaging economically than commonly believed, and that aggressive mitigation strategies could be more harmful than beneficial.' Many of the arguments reflected in the new DOE paper, mainstream scientists told WIRED, have been debunked over and over for years. 'I'm a bit surprised that the government put out something like this as an official publication,' Zeke Hausfather, the climate research lead at tech company Stripe and a research scientist at the climate nonprofit Berkeley Earth, told WIRED in an email. 'It reads like a blog post—a somewhat scattershot collection of oft-debunked skeptic claims, studies taken out of context, or cherry-picked examples that are not representative of broader climate science research findings.' The DOE says that it is opening the report up to a public comment process. In an email, Department of Energy spokesperson Andrea Woods said that the questions WIRED sent over about the use of research in specific portions of the report were too complex for the agency to answer thoroughly on a short turnaround, and encouraged scientists who spoke with WIRED to submit a public comment to the federal register. 'The Climate Working Group and the Energy Department look forward to engaging with substantive comments following the conclusion of the 30-day comment period,' Woods wrote. 'This report critically assesses many areas of ongoing scientific inquiry that are frequently assigned high levels of confidence—not by the scientists themselves but by the political bodies involved, such as the United Nations or previous Presidential administrations. Unlike previous administrations, the Trump administration is committed to engaging in a more thoughtful and science-based conversation about climate change and energy.' Ben Santer, a climate researcher and an honorary professor at the University of East Anglia, has a long history with some of the authors of the new report. (Santer's research is also cited in the DOE report; he, like other scientists who spoke to WIRED, say the report 'fundamentally misrepresents' his work.) In 2014, Santer was part of an exercise at the American Physical Society (APS), one of the largest scientific membership organizations in the country. Known as a red team vs blue team exercise, it pitted proponents of mainstream climate science against contrarians—including two authors of the current DOE report—to work through whether their claims had merit. The exercise was convened by Steve Koonin, one of the new hires at the Department of Energy and an author of the report. As Inside Climate News reported in 2021, Koonin resigned from his leadership role after APS refused to adopt a modified statement on climate science that he proposed following the exercise. Koonin later unsuccessfully pitched a similar exercise to the first Trump White House. 'These guys have a history of being wrong on important scientific issues,' Santer says. 'The notion that their views have been given short shrift by the scientific community is just plain wrong.' Hausfather's work is cited twice in the report in a section challenging emissions scenarios: projections of how much CO 2 will be emitted into the atmosphere under various different pathways. These citations, Hausfather says, are 'instructive' to see how the DOE report's authors 'cherrypick data points that suit their narrative.' The report includes a chart from a 2019 paper of his that, the DOE authors say, shows how climate models have 'consistently overestimated observations' of atmospheric CO 2 . However, Hausfather tells WIRED, the key finding of his 2019 research was that historic climate models were actually remarkably accurate in predicting warming. 'They appear to have discarded the whole paper as not fitting their narrative, and instead picked a single figure that was in the supplementary materials to cast doubt on models, when the whole paper actually confirmed how well they have performed in the years after they were published,' he tells WIRED. (Hausfather's research was also cited in the EPA's justification for rolling back the endangerment finding—which, he said in a post on X, draws a 'completely backwards' conclusion from his work.) It's not just Hausfather who feels his work was mishandled. Much of the early section of the report discusses how beneficial carbon dioxide is to plant growth, a claim that has been repeated by Secretary Wright as a 'plus' to global warming. The authors cite 2010 research from evolutionary biologist Joy Ward, now the provost and executive vice president of Case Western Reserve University, to support claims that plant life will flourish with more CO 2 in the atmosphere. Ward, however, told WIRED in an emailed statement that her experiments were conducted under 'highly controlled growth conditions' to create a 'mechanistic understanding' of CO 2 , and that climate change can cause a host of impacts on plants not accounted for in her study. 'With rising CO 2 in natural ecosystems, plants may experience higher heat loads, extreme weather events such as droughts and floods, and reduced pollinators—which can have severe net negative effects on plant growth and crop yields,' she says. 'Furthermore, our studies indicate that major disruptions in plant development such as flowering time can occur in direct response to rising CO 2 , which were not mentioned in the report.' The DOE report's section on ocean acidification cites research by Josh Krissansen-Totton, an assistant professor at the University of Washington who specializes in planetary science and biogeochemistry, to support a claim that 'the recent decline in [ocean] pH is within the range of natural variability on millennial time scales.' Research has shown that the oceans have been absorbing CO 2 from the atmosphere since the beginning of the industrial revolution, causing it to become considerably more acidic over the past two centuries. 'Ocean life is complex and much of it evolved when the oceans were acidic relative to the present,' that section of the report states. 'The ancestors of modern coral first appeared about 245 million years ago. CO 2 levels for more than 200 million years afterward were many times higher than they are today.' Krissansen-Totton told WIRED in an email that his work on ocean acidity billions of years ago has 'no relevance' to the impacts of human-driven ocean acidification today, and that today calcium carbonate saturation is quickly diminishing in the ocean alongside rising acidity. Dissolved calcium carbonate is essential for many marine species, particularly those that rely on it to build their shells. 'The much more gradual changes in ocean pH we observe on geologic timescales were typically not accompanied by the rapid changes in carbonate saturation that human CO 2 emissions are causing, and so the former are not useful analogs for assessing the impact of ocean acidification on the modern marine biosphere,' he says. The consensus among mainstream academics around climate change's severity and importance does not mean that there aren't still open questions about portions of the science. Jeff Clements, a marine ecologist who runs a research lab at Canada's federal fisheries and ocean department, says that the way the DOE report cites his research on ocean acidification and fish behavior is accurate 'from an explicit textual perspective.' Clements's work on this topic focuses on correcting alarming earlier studies connecting the effects of ocean acidification on fish. In the DOE report, his work is used to bolster the section downplaying ocean acidification. 'Much of the public discussion of the effects of ocean 'acidification' on marine biota has been one-sided and exaggerated,' the DOE report states. Clements said in an email to WIRED that just because his review of the literature found fish behavior to be relatively unaffected by ocean acidification does not mean that a myriad of other ocean ecosystems, biological processes, and species will fare similarly. Other work from his lab, meanwhile, has underscored the vulnerability of mussels to ocean warming and looked at how heatwaves negatively alter clam behavior. 'I want to make it clear that our results should not be interpreted to mean 'ocean acidification (or climate change more generally) is not a problem,'' he tells WIRED. 'While effects on fish behavior may not be as severe as initially thought, other species and biological processes are certainly vulnerable to the impacts of acidification and the compendium of other climate change stressors that our oceans are experiencing.' Richard Seager, a research professor at the Lamont-Doherty Earth Observatory of Columbia University, coauthored a paper cited in the DOE report on the discrepancy between what climate models predict and what is actually being measured when it comes to sea-surface temperatures in the Pacific Ocean. 'I think acceptance has been growing that the models have been getting something wrong in the tropical Pacific,' he says. 'That and what this means for the future however is very much an area of intense research.' (A separate study on agricultural yields coauthored by Seager, he says, is misrepresented in another section of the report.) The future of further research on this topic and other open questions in climate science is in limbo six months into the second Trump administration. The irony of the report's promotion at a time when the White House is launching multiple fronts of attacks on traditional science—including removing the authors of the National Climate Assessment from their roles in April—is not lost on mainstream scientists. 'This report had five authors and was rushed over four months, and would not pass muster in any traditional scientific peer-review process,' says Hausfather. 'The fact that this has been released at the same time that the government has hidden the actual congressionally mandated national climate assessments that accurately reflect the science only further shows how much of a farce this is.'
Yahoo
3 hours ago
- Yahoo
How Many Steps a Day You Actually Need, According to New Research
Good news: You don't need to hit 10,000 steps a day to improve your health. According to a new study published in The Lancet Public Health, you can experience roughly the same benefits with fewer steps—around 7,000 per day. Researchers from the University of Sydney reviewed and analyzed long-term studies conducted between 2014 and 2025 that tracked people's daily steps and various health risks, such as type 2 diabetes, cardiovascular disease, cancer, cognitive function, and mental health, as well as overall mortality. Compared to walking 2,000 steps a day, the study found that walking 7,000 steps lowered the risk of dementia by 38%, type 2 diabetes by 22%, and cardiovascular disease by 25%. Researchers concluded that the incremental improvement beyond 7,000 steps per day was small, but they acknowledged that some figures may be less accurate than others because they were drawn from only a small number of studies. The researchers added that even a modest step count can help lower health risks. "For example, 4,000 steps per day compared with 2,000 steps per day was associated with substantial risk reduction, such as a 36% lower risk in all-cause mortality ... the message that every step counts for those who are able should be emphasized as a core public health message, regardless of the specific quantitative target." According to the study, the goal of 10,000 steps a day is an unofficial target without any clear evidence—it actually started as part of a marketing campaign in Japan. And while that many steps a day can be a good goal for active individuals, the researchers report that 7,000 steps per day "might be a more realistic and achievable target for some." Read the original article on Martha Stewart
Yahoo
4 hours ago
- Yahoo
Huge hidden flood bursts through the Greenland ice sheet surface +EMBARGO 0900GMT 30 July 2025+
A sudden flood from a hidden lake beneath Greenland's ice sheet reveals a powerful meltwater process not currently accounted for in climate change models. As global warming intensifies, researchers say the discovery highlights the need to better understand how ice sheets respond to extreme melts.
