Toxic algae bloom kills hundreds of marine species in Australia
The algae, Karenia mikimotoi, has spread across more than 150km of coastline since it was first detected in March, nearly the size of the Kangaroo Island.
Since the algae appeared, local people and scientists have observed mass deaths of fish, shellfish, sharks, sea dragons, rays, cuttlefish, and deepwater species along the southern coastline.
South Australia 's environment minister said the outbreak had grown to an unprecedented scale. "It is a larger bloom than we have ever seen before," Susan Close said.
Scientists say that it is being fuelled by an ongoing marine heatwave, with sea temperatures 2.5C above average, and calm conditions that allow it to thrive.
Described as a 'toxic blanket', the bloom suffocates fish by damaging their gills and attacking red blood cells and the nervous system. It can lead to haemorrhaging and erratic behaviour in affected animals. 'It is like a horror movie for fish,' Brad Martin of OzFish told The Guardian.
Ms Close said there was not much the government could do. "The only thing that is going to break this bloom up is a change in the weather and starting to get strong westerly winds," she said.
An analysis of over 1,400 citizen science reports found around half of the dead species were ray-finned fish and more than a quarter were sharks and rays. Cephalopods like squid and cuttlefish and crustaceans such as crabs and lobsters were among the affected species as well.
Though not toxic to humans, the algae has caused skin irritation and respiratory symptoms in some beachgoers.
Authorities have temporarily closed several oyster farms and banned pipi harvesting in parts of South Australia.
An alarm about the bloom was first sounded by beachgoers back in March after thick foam and dead marine animals washed up on Waitpinga and Parsons beach on the Fleurieu Peninsula.
Professor Shauna Murray, a marine biologist at the University of Technology Sydney, identified the algae under a microscope and through DNA analysis.
She told The Guardian that K mikimotoi was known to produce reactive oxygen that could suffocate marine life.
South Australia's government said winds needed to disperse the algal bloom were being delayed by persistent high-pressure systems – another symptom of shifting climate patterns.
Authorities say the full ecological and economic impact of the bloom is yet to be understood but environmental groups urge improved monitoring and stronger action on marine heatwaves, which are growing much more frequent as oceans continue to warm.
Alongside the marine heatwave, southern Australia is suffering through one of the worst droughts on record.
Ms Close sounded the alarm on how climate change was making the crisis worse.
The minister said ocean monitoring showed 'a full-scale climate emergency in our coastal waters', with the bloom extending across an area roughly the size of Kangaroo Island and up to 20m deep.
'These extreme marine heat waves are not just anomalies, they are the new reality. And our marine ecosystems are the first casualties.'
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The Guardian
3 days ago
- The Guardian
SA's toxic algal bloom is twice the size of the ACT, has killed 12,000 animals and is filling even the experts with dread
Anthony Rowland was heading out for a pre-dawn surf at Waitpinga Point when he felt a tickle in his throat. He was out on the pristine water as the sun rose on South Australia's Fleurieu Peninsula, then headed back up the hill towards the car park with his friends. 'Halfway up, all three of us were barking,' he says. When they reached the car park, it was full of people coughing. 'That was the second I realised something really bad was going on,' he says. It was Saturday, 15 March. When he went back the next day, a sickly yellow-brown foam had been whipped up along the shoreline. Dead leafy seadragons and fish carcasses littered the shore. Rowland – a surfer from nearby Victor Harbor who can now be described as a citizen scientist – tried to alert authorities, without success. Then the media began reporting about the mysterious foam, and asking questions about its links to symptoms in humans and death among sealife. It was the first time the wider population had heard of the devastating, toxic algal bloom that has left SA beaches littered with the carcasses of fish and marine animals – but it had already been brewing away beneath the waves for some time. Estuarine ecologist Faith Coleman thinks it was killing fish as early as January. About a week after Rowland started to tell anyone who'd listen about what was happening at Waitpinga, authorities confirmed the main algal species was Karenia mikimotoi, a type of plankton that had grown out of control. Experts say other algae that produce toxins are likely to be in the bloom as well. The toxins affect the gills of fish, while the bloom sucks the oxygen out of the water as it dies and decomposes, effectively suffocating marine life. It appears in the water and on the sand as a dirty stain, and in the air as an irritant to eyes and lungs. According to records, it has killed over 12,000 animals from almost 400 species so far, but experts predict the figure is much higher. There are dead fiddler rays, worm eels, Port Jackson sharks, crabs and puffer fish. There are starfish and scallops, sea cucumbers, wobbegongs and flatheads. A persistent marine heatwave affects the waters off South Australia, kicked off with sea surface temperatures reaching 2.5C above average. A mysterious sea foam appears at beaches on the Fleurieu Peninsula, with reports of more than 100 surfers becoming ill, and deaths of leafy sea dragons, fish and octopi. Marine biologists from the University of Technology Sydney find high numbers of a tiny harmful algal species called Karenia mikimotoi in water samples collected from affected beaches. Prof Shauna Murray – who identified the algae under the microscope and by analysing its DNA – says while still not well understood, K mikimotoi is thought to produce a reactive oxygen that caused gill cell damage in fish – which means they can not breathe. By this point, more than 200 marine species have been killed by the bloom, which stretches along more than 150 kilometres worth of coastline. A powerful storm and high tides washes the algae into the Coorong, staining the water like strong tea before turning it into a slurry. Water testing confirms the presence of the algae in the Coorong. Abnormally high tides, strong winds and large waves lashes the South Australian coastline, with multiple reports of fish deaths along the Adelaide metropolitan coastline reported in the aftermath. Testing confirms the toxic algae had entered West Lakes. While the algae has been detected at the inlet, it had not yet been detected at three other testing sites. It's not toxic to humans or other mammals but can cause averse reactions such as coughing, throat irritation and eye inflammation. According to state government experts, there are several 'plausible' factors that triggered the deadly algae bloom. In 2022, deadly floods hit the eastern states. That water flowed through the Murray-Darling Basin, collecting organic matter on its way. Eventually, the nutrient-rich water made its way to SA's River Murray before oozing out into the ocean. The next summer, there was an 'upwelling' of that water, bringing it to the surface. And then a marine heatwave began in September 2024. Sea temperatures rose to about 2.5C above normal. It was hot, dry and calm. And the bloom grew. It spread from the Fleurieu Peninsula, to Kangaroo Island, Yorke Peninsula, Gulf St Vincent and the Spencer Gulf. It grew to 4,500 sq kms – almost double the size of the ACT – and as deep as 20m. In June it infiltrated the Coorong, a delicately balanced ecosystem and Ramsar-listed wetlands, and in early July it made its way to metropolitan beaches and into the Port River, which is home to a dolphin sanctuary. The bloom killed invertebrates and organisms that anchor seagrasses, leaving beaches near Adelaide strewn with clumps of seaweed. Nestled in those clumps are dead animals in states of decay. Beachgoers can be seen walking between carcasses, frantically calling their dogs away from the rotting fish. It has forced oyster and mussel farms to close, and has caused huge complications for the marine tourism industry. 'People have seen what's washed up on the shoreline, but that's just the tip of the iceberg,' marine biologist and underwater cinematographer Stefan Andrews says. Andrews is the co-founder of the Great Southern Reef Foundation (GSRF), which has been tracking the bloom. 'All of the habitats that these marine creatures depend on are deteriorating,' he says. 'But it's happening underwater and it's going unnoticed.' Footage from his dives contrast colourful, vibrant underwater scenes from before the bloom with murky after-shots that look almost apocalyptic. And there's 'weird' stuff going on, Andrews says. Critters you'd normally see at night appearing during the day. Abalone sitting upside down. A brittle star – related to the starfish, but with long, spindly arms – has its middle missing, like a doughnut. 'It seems to be rotting away from the inside.' When he looked under the kelp canopy while diving off Kangaroo Island, the invertebrates, the sponges, the sea squirts, were 'all dead or dying and falling apart'. As is always the case in the modern world, conspiracy theories have sprung up around the bloom. Some say Chinese warships caused it, others blame the desalination plant, some blame cloud seeding. Estuarine ecologist Faith Coleman says people are desperate for answers. 'I'm spending an awful lot of time doing something I hate to do, which is myth busting, whereas I'd prefer to be concentrating on solving the problem,' she says. She also says the contribution of the Murray floods and the upwelling were minor contributors. Overwhelmingly, she says, it was the marine heatwave. The government and experts concede there are many unanswered questions – including when it will end. The state government says nothing can be done naturally to dilute or dissipate the bloom. That won't quell the rising calls for action. The GSRF wrote to the federal government in 2023, warning of the likely impact of marine heatwaves. It wrote again in May this year, calling for a $40m, 10-year investment in a monitoring program. It didn't hear back. 'We need a coordinated monitoring program,' Andrews says. 'So when events like marine heatwaves happen, we're able to learn from them as they're unfolding and gather valuable data.' Federally, the Greens are calling for an inquiry and for it to be declared a national disaster, 'just like a bushfire or a weather bomb', SA senator Sarah Hanson-Young says. The Greens senator adds that if it was happening anywhere else in the country, the federal government would be on it. Sign up for Guardian Australia's breaking news email The state government says it's working with commercial fishers, tourism operators and councils, and set up a reference group to report to a taskforce to discuss any updates. A patrol vessel and remotely operated vehicles have been sent to conduct underwater observations. It's also asking the federal government to fund more research and recovery measures. On Wednesday the federal environment minister, Murray Watt, sent his department's head of international environment, reef and ocean division to SA to ensure he has 'the best possible advice on the situation'. Coleman, to whom everyone seems to defer as a top expert on the bloom and who previously worked on projects including dealing with the carp in the Murray, recently captured plenty of attention talking about the 'sea sparkle'. It's different algae that can eat the Karenia – an appealing concept. But there's not enough of the luminescent algae to make a significant difference. The colder water and storms might be dispersing the bloom a bit, Coleman says, but more is needed to flush the gulfs or there'll be another bloom this summer. Restoring things such as the seagrasses and kelp forests, which work to suppress fledgling blooms and act as carbon sinks, would help, she says. What most people agree on is that more data and more transparency is needed, and that climate change is the driving force that needs to be stopped. Rowland, four and a half months after he started coughing in the car park, has become a citizen scientist embedded in a network of volunteers who are monitoring and logging the fish deaths on the iNaturalist app. 'Because the world's heating up,' he says. 'I just don't feel confident that once it's gone, it's gone. 'For me, the writing's on the wall.'
The Guardian
4 days ago
- The Guardian
This Jurassic-era relic has survived 150 million years on Earth – now it's one big fire from extinction
For the last five weeks, Jane Ogilvie has searched a patch of dense shrub shaded by sugar gums on Kangaroo Island in South Australia for a surviving relic from 150m years ago. The only known home of the critically endangered Kangaroo Island assassin spider is in the north-west of the island, where the Jurassic-era spider hides out in moist clumps of leaf litter. In more than a month of searches, and with just a couple more weeks to go, Ogilvie and a few helpers have only found one tiny juvenile. 'We get so excited when we find a good area but then it's deflating. Everything is so dry – it's hardly rained for two years,' says Ogilvie, a conservation biologist working with the charity Invertebrates Australia. Last year, scientists found just one mature female and six juveniles at six locations, all in a 20 sq km area that includes a block of land owned by mining billionaire Andrew Forrest. Those same locations have come up blank this year. The spiders need the moist microclimate of the leaf litter to survive, but there's a trifecta of threats drying out their habitat and pushing them ever closer to extinction. The spider's last remaining bolthole has been through near-record drought over the last 18 months, with rainfall among the lowest on record since 1900. The black summer bushfires burned through large areas of potential habitat that have not yet recovered, and an invasive plant root disease known as phytophthora is damaging the forest canopy and the plants that hold some of the leaf litter where the spiders live, drying out the habitat even further. Sign up for Guardian Australia's breaking news email 'If we look at the risks and [are] realistic, they're potentially one big fire away from extinction,' says Dr Michael Rix, the principal scientist and curator of arachnology at the Queensland Museum, who collected the first specimens of the spider and, with scientific colleague Mark Harvey, formally described them. 'By all objective measures, its existence is phenomenally precarious.' The Kangaroo Island assassin spider is one of 11 invertebrates on the federal government's priority list of threatened species. The assassin family of spiders – which get their name from their habit of slowly stalking and then eating other spiders – are found only in Australia, Madagascar and parts of southern Africa. Kangaroo Island's assassin was found in 2010 by Rix, who, along with Harvey, has described 37 of Australia's 41 assassin spiders. 'We collect this suspended leaf litter and shake it. The spiders close their legs and they drop down. I looked in the tray to see what's there – I knew it was undescribed. It was one of the really memorable moments of my field biology career. Very exciting,' he remembers. Rix says they have the most unusual appearance of any spider, with 'incredible elevated heads and long spear-like mouth parts'. 'They're unmistakeable,' he says. 'They're an early branch in the spider's tree of life. Assassin spiders are ancient and those around today are survivors of 150m years of life on Earth. 'They were only known as fossils before any living ones were found in Madagascar in the 19th century.' Sign up to Breaking News Australia Get the most important news as it breaks after newsletter promotion Kangaroo Island's species was feared extinct after bushfires swept across the west of the island in the black summer bushfires of 2019 and 2020 until Dr Jess Marsh, a research fellow at the University of Adelaide and an invertebrate conservation biologist based on the island, found two specimens in 2021 in a small patch of unburned vegetation. 'It's being squeezed into smaller and smaller areas,' says Marsh. 'Each survey we do is increasing our confidence that its restricted to this patch of vegetation, and nowhere else.' Marsh and colleagues are now discussing the idea of establishing a breeding program for the spiders in a zoo, creating an 'insurance population' – but removing individuals from the wild carries clear risks that Marsh says wouldn't be taken lightly. 'They've survived mass extinction events and past climate changes – a huge amount. Now in this short period of time, it's humans that are really testing them.' Rix says the precarious situation the spiders find themselves in is part of a much bigger wave of largely unseen extinctions of invertebrates. Officially, Australia lists only one invertebrate as extinct – the Lake Pedder earthworm. But last year, Rix, Marsh and colleagues released research that estimated that since the European invasion of Australia, about 9,000 invertebrates had likely suffered a so-called ghost extinction – 'the loss of undiscovered species that have left no trace.' 'Some people might say, 'who cares about a tiny spider going extinct'?' says Rix. 'But this is part of the quantum of invertebrate extinctions that we're experiencing right now. This might be a problem that creeps up on us. 'There's a concept of conserving evolutionary significant units – retaining diversity that speaks deeply to Earth's evolutionary history. That is what these spiders are – a window into the past. They're survivors. Trying to conserve them is so important.' Marsh and Rix were the only two people to have ever found a Kangaroo Island assassin spider, until this week's discovery – not by a scientist, but an enthusiastic 17-year-old volunteer called Jack Wilson who was filling his time during school holidays. 'It was probably my 10th sieve of the day,' he says. 'They can look like little blobs of dirt, but it's the big neck that gives them away. I'm pretty chuffed. It's crazy.'
BBC News
5 days ago
- BBC News
Rare sea Warty Doris slug photographed in Studland Bay
Spotting a rare sea slug in UK waters was "absolutely incredible" says an underwater Munn from Swanage, Dorset, captured the Warty Doris near Old Harry's Rocks in Studland Bay earlier this ocean lover who volunteers with Seasearch, a project led by the Marine Conservation Society, said she was "so excited" and had to "do a double take".The slug is usually found off France, Belgium and Spain, and in the waters of the Mediterranean, Adriatic and west Atlantic. Seasearch and Dorset Wildlife Trust confirmed that Ms Munn's discovery was the species of nudibranch, which gets it name from the warts all over its body. "It's normally associated with warmer waters so it's possibly an indicator of climate change," Ms Munn said there were quite a few of the bright yellow and orange creatures, which can range in length from 30mm to 70mm."It actually breathes through it's bottom so it's quite a cute species," she environmentalist was also able to capture an image of the brightly coloured Warty Doris eggcase, which the slug's use to protect their eggs. Ms Munn fell in love with the ocean after she used swimming and snorkelling to aid her recovery following a series of car said she is out exploring and snorkelling along Dorset's coastline on a daily blogs her findings, in the hope that it will inspire others to make new discoveries in the local waters."I just want to raise awareness of the marine life that we can find around here and how colourful and beautiful it is," she said. You can follow BBC Dorset on Facebook, X (Twitter), or Instagram.
