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Scientific American
4 days ago
- Health
- Scientific American
Mysterious Illness Decimating Sea Stars Finally Identified
A mysterious illness has killed billions of sea stars in the past decade. After a four-year search, scientists have uncovered the culprit: a bacterium known as Vibrio pectenicida. The team reported its findings this week in Nature Ecology & Evolution. The strange illness is known as sea star wasting disease, and it causes starfish to disintegrate to death. It is the largest marine epidemic among noncommercial species that has ever been documented, and it has affected more than 20 species of sea stars along the Pacific Coast of North America. Approximately 90 percent of sunflower sea stars (Pycnopodia helianthoides) have died from the ailment, so many that they are now a critically endangered species. On supporting science journalism If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today. Researchers are unsure of where this bacterium came from and why it broke out. But there is evidence that warmer ocean temperatures are linked to bigger outbreaks. In British Columbia, the most severe outbreaks happen late in the summer, says study co-author Alyssa Gehman, a marine disease ecologist at the province's Hakai Institute and the University of British Columbia. And that suggests that temperature and possibly even climate change might affect this disease. 'Sea stars [such as] sunflower stars are really important members of their communities,' Gehman says. When the sunflower sea stars lost about 90 percent of their population, there were huge increases in sea urchins (a prey of sea stars) off the coast of California. The spiny creatures are massive grazers of kelp forests, which are crucial members of marine ecosystems, Gehman says. Underwater kelp forests store carbon and are homes for thousands of species. But once sea urchin populations boomed, there was a widespread loss of kelp forests. To identify the disease, researchers ran more than 20 experiments from 2021 to 2024. In one experiment, they analyzed the genes of eight healthy sea stars and eight infected ones. While sitting in her office and comparing the genetics of the two groups, Melanie Prentice, a research scientist now at the Hakai Institute, thought, 'Gosh, there's so much Vibrio in these wasting sea stars, and there's really not much happening in these healthy sea stars in terms of Vibrio.' After toggling the data to see the specific Vibrio species, she found V. pectenicida in every single one of the wasting sea star samples. To validate the finding, Prentice and her team exposed healthy sea stars to V. pectenicida. From the 20 sunflower stars that the researchers exposed to V. pectenicida at varying doses, only one survived (this sea star was exposed to the lowest dose of the bacteria tested). The rest died from sea star wasting disease, providing the conclusive evidence the team needed, Prentice says. 'If you don't know what it is that's killing them, there's only so much you can do to try and save them,' Gehman says. 'So, there's a bunch of work that we can do now.' One next step is to determine if the pathogen is unique to the sunflower sea star because there are still many other species affected by the disease, says Oregon State University marine ecologist Bruce Menge, who wasn't involved in the study. Prentice and her colleagues hope to breed sea stars that are resistant to the pathogen so they can survive in the wild. It's Time to Stand Up for Science Before you close the page, we need to ask for your support. Scientific American has served as an advocate for science and industry for 180 years, and we think right now is the most critical moment in that two-century history. We're not asking for charity. If you become a Digital, Print or Unlimited subscriber to Scientific American, you can help ensure that our coverage is centered on meaningful research and discovery; that we have the resources to report on the decisions that threaten labs across the U.S.; and that we support both future and working scientists at a time when the value of science itself often goes unrecognized.
Los Angeles Times
5 days ago
- Health
- Los Angeles Times
Researchers figure out what's caused devastating sea star epidemic
A study published Monday offers long-awaited clarity on a more than decade-long marine mystery: What has been killing the sunflower sea star? In 2013, something began ravaging sea stars along the West Coast, turning them into decaying, fragmented carcasses. Over the next few years, the wasting disease (SSWD) killed billions of animals along the shore, transforming entire marine ecosystems. One species was hit especially hard: Pycnopodia helianthoides, more commonly known as the sunflower sea star. Scientists estimate the global population plummeted by 94% since 2013. California alone lost about 99% of its sunflower sea stars. For over a decade, nobody knew what was responsible. In their paper in Nature Ecology & Evolution, researchers have now identified the culprit behind the devastating epidemic — and with it, a path forward for restoration. 'This was a big deal for us,' said Alyssa Gehman, a marine disease ecologist at Hakai Institute and the University of British Columbia and senior author on the study. 'When we started these experiments, I knew we would learn more, but I honestly wasn't convinced we would actually find the causative agent of disease.' The breakthrough came during a routine meeting between Gehman and two collaborators, Grace Crandall and Melanie Prentice. They had recently tested whether heat-treated coelomic fluid — the internal body fluid of a sea star — could still trigger the disease when injected into a healthy sea star. When the injected sea stars stayed healthy, it confirmed that the disease was being caused by something that was alive. To find out what that 'something' was, the team turned to a set of techniques that reveals which genes are being expressed by what microorganisms. When they compared healthy and infected animals, one group consistently stood out—the Vibrios, a type of bacteria commonly found in marine environments. Knowing there are many Vibrios, the researchers were curious whether the wasting sickness could be tied to one in particular. Prentice ran the species-level analysis, and the result floored them. 'The whole list was Vibrio pectinocida. And it was in all of our six stars and it was in none of our controls,' Gehman said. It was 'mind-blowingly clear' that this bacteria was causing the disease, she said. For California's kelp forests, and the conservation groups trying to save them, this news is a major turning point. Sunflower sea stars are considered a keystone species, meaning they are critical in regulating the stability and diversity of their ecosystems. One of their most important roles is controlling purple sea urchin populations, a species with a notoriously voracious appetite. 'They can mow down a kelp forest and then actually remain in that ecosystem without a food source,' said Prentice, a marine biologist and study co-author. 'They enter almost like a zombie state until the kelp regrows — and then they eradicate it again.' Sunflower sea stars used to prey on the urchins, keeping their population in check. However, when wasting disease effectively wiped out their main predator, the sea urchins exploded in number, decimating kelp forests and transforming once-lush underwater habitats into so-called 'urchin barrens.' 'Kelp forests are the most important ecosystem on our coast because they house over 800 species of animals,' said Nancy Caruso, marine biologist and founder of the nonprofit Get Inspired. 'Essentially, they're the condos and apartment complexes of the animals that live on our coastline — and when they disappear, they have no place to live.' Kelp forests also filter water, store carbon, and protect coastal communities from storms and erosion, making them, as Prentice described, 'an ally in our fight against the climate crisis.' Since the 2013 outbreak, areas like Northern California have lost more than 95% of their kelp forest cover. Several sites are still considered ecological collapse zones. Researchers say recovery can now be more targeted. Prentice is currently developing a diagnostic test similar to a COVID rapid test, which could help screen animals and seawater for the presence of Vibrio pectinocida before conservationists reintroduce sea stars into the wild. 'That's going to be powerful not just for research, but for management,' she said. 'Now we can actually test animals before we move them — or test the water at a potential outplanting site and say, is this a good place for reintroduction?' Other teams are looking at breeding disease-resistant sea stars. Surviving populations may have natural immunity, which could help shape more resilient captive-rearing programs. At the Aquarium of the Pacific in Long Beach, which cares for some of the surviving sunflower stars, the new findings could help reshape priorities. 'It sharpens our focus on what it might take to reintroduce these animals in a way that is thoughtful, informed, and sustainable,' said Johnathan Casey, the aquarium's curator of fish and invertebrates. 'With each new piece of the puzzle, we feel we're getting closer to a future where sunflower stars can once again thrive along our coastline.' Sunflower sea stars used to be everywhere — on sand, rocks, kelp beds, and seagrass beds. For Gehman, that's the point. She hopes the findings help people realize that even the most abundant species can disappear very quickly.
Global News
5 days ago
- Health
- Global News
What killed the sea stars? Canadian researchers unlock 12-year-old mystery
A team led by researchers in British Columbia has solved the mystery of a gruesome disease that has killed billions of sea stars along the Pacific coast of North America, more than a decade after the die off. Melanie Prentice, the lead author of a new study, recalls a moment of 'not really believing it' when researchers found a strain of bacteria that was abundant in diseased sea stars and absent in healthy ones. 'My initial reaction was like, 'Okay, so I've done something wrong,'' she said. Prentice said the team spent months trying to disprove their findings, ultimately confirming they had cracked the code of the disease. They found the bacterium Vibrio pectenicida is a clear cause of sea star wasting disease. '(It's) a question that researchers have been trying to answer for about 12 years, so we're beyond thrilled,' said Prentice, a research associate at the Hakai Institute and the University of B.C. department of earth, ocean and atmospheric sciences. Story continues below advertisement The paper detailing the four-year research project and its findings were published online in the peer-reviewed journal Nature Ecology & Evolution on Monday. Alyssa Gehman, who helped launch the project in 2021, described the disease as 'gruesome,' causing sea stars to develop lesions, lose their arms and 'disappear into mush' about a week or two after exposure to the pathogen. It has been especially deadly for sunflower sea stars, killing about six billion of the species that can sprout 24 arms and span up to a metre. The giant sea stars are now considered functionally extinct across much of their former range off the coast of the continental United States, with losses exceeding 87 per cent in the 'northern refuges' where they still persist, the study said. The collapse has had cascading impacts, including widespread losses of ecologically, culturally and economically important kelp forests. 'I think we didn't really appreciate how important they were until we lost them,' Prentice said, describing the orange, purple or brown sunflower stars as a 'keystone' species with an outsized impact on their ecosystem. Get breaking National news For news impacting Canada and around the world, sign up for breaking news alerts delivered directly to you when they happen. Sign up for breaking National newsletter Sign Up By providing your email address, you have read and agree to Global News' Terms and Conditions and Privacy Policy The giant sea stars are top predators, striking fear into other invertebrates. 'Almost everything that lives on the ground underwater runs away from them when they're coming,' said Gehman, a marine disease ecologist at the Hakai Institute and an adjunct professor at the University of B.C.'s Institute of Oceans and Fisheries. Story continues below advertisement They keep sea urchin populations in check, in turn ensuring the health of help forests that provide habitat and food for numerous other species. The devastation of the sunflower sea stars has caused a 'total ecosystem shift,' Prentice said, transforming biodiverse kelp forests into 'urchin barrens.' The bacterium that causes sea star wasting disease had remained elusive for more than a decade since sea stars were first observed dying in large numbers in 2013. The same bacterium has been known to attack scallop larvae. Prentice said the breakthrough came after the research team switched from examining diseased tissues to focusing on the sea stars' coelomic fluid, likening it to the blood of the sea star. Earlier research had involved running the tissues through tiny membrane filters that would have excluded bacteria, which are typically larger than viruses, she explained. The Hakai Institute team started by replicating the initial experiments, but they weren't able to cause disease in healthy sea stars, she said. 'We were doing everything we could and we were just never ever able to cause disease, and so to us that suggested that the pathogen is larger than a virus.' However, after pivoting to coelomic fluid, which Prentice described as 'essentially sea water,' the researchers did trigger disease in healthy sea stars. Story continues below advertisement 'That suggested that the pathogen was in that fluid, and so then we just end up working with a much cleaner, easier tissue type to investigate,' she said. From there, Prentice created a list of all the different microbial species found in wasting sea stars and compare it against the healthy stars in the lab. 'I finally got to a place where I generated these different lists and it was very evident right away that there (were) tons of different Vibrio species within our wasting sea stars and we weren't really seeing that in our healthy sea stars,' she said. Prentice said she then filtered the genetic data to look at each strain of Vibrio bacteria, which led to their eureka moment with Vibrio pectenicida. 'We just saw it in every single wasting sea star sample, and then we looked at our controls and it was just not in any of them,' she said. Prentice said other researchers had wished her 'good luck' when she joined the project, but there was skepticism over whether they would solve the mystery. It felt 'incredible' to be part of a discovery that could help make a meaningful difference in the recovery of sea stars and their ecosystems, she said. Gehman, too, said she wasn't sure the project would result in a singular answer. Story continues below advertisement 'I thought it would be complicated. I thought there would be multiple things relying on other things,' she said. 'This was much clearer than I was expecting.' The discovery allows researchers to turn their efforts to deeper questions, including the possible role of warming ocean temperatures and the potential to breed sea stars in captivity to promote disease resistance and spur recovery, she said. The disease now appears to be seasonal, with outbreaks occurring in the warmer months, suggesting temperature may be a factor, said Gehman, adding she will soon conduct temperature experiments to investigate further. 'Does Vibrio pectenicida grow faster at warmer temperatures and the sea star can sort of survive at the growth rates at cooler temperatures, but when you get to warmer temperatures, they can't, is that what's happening?' The findings could help researchers understand where sea stars may struggle or survive with climate change in the future, Gehman said. Prentice said there are 'remnant' populations of sunflower stars along the B.C. coast, and its 'very possible' some could be more resistant to the wasting disease. She said finding and selectively breeding sea stars with a higher capacity to fight off the disease could produce 'superstar' sea stars for reintroduction in the wild. 'It seems like science fiction sometimes, but people are working on it,' she said.
Winnipeg Free Press
5 days ago
- Health
- Winnipeg Free Press
Canadian researchers solve 12-year mystery of sea star wasting disease
A team led by researchers in British Columbia has solved the mystery of a gruesome disease that has killed billions of sea stars along the Pacific coast of North America, more than a decade after the die off. Melanie Prentice, the lead author of a new study, recalls a moment of 'not really believing it' when researchers found a strain of bacteria that was abundant in diseased sea stars and absent in healthy ones. 'My initial reaction was like, 'Okay, so I've done something wrong,'' she said. Prentice said the team spent months trying to disprove their findings, ultimately confirming they had cracked the code of the disease. They found the bacterium Vibrio pectenicida is a clear cause of sea star wasting disease. '(It's) a question that researchers have been trying to answer for about 12 years, so we're beyond thrilled,' said Prentice, a research associate at the Hakai Institute and the University of B.C. department of earth, ocean and atmospheric sciences. The paper detailing the four-year research project and its findings were published online in the peer-reviewed journal Nature Ecology & Evolution on Monday. Alyssa Gehman, who helped launch the project in 2021, described the disease as 'gruesome,' causing sea stars to develop lesions, lose their arms and 'disappear into mush' about a week or two after exposure to the pathogen. It has been especially deadly for sunflower sea stars, killing about six billion of the species that can sprout 24 arms and span up to a metre. The giant sea stars are now considered functionally extinct across much of their former range off the coast of the continental United States, with losses exceeding 87 per cent in the 'northern refuges' where they still persist, the study said. The collapse has had cascading impacts, including widespread losses of ecologically, culturally and economically important kelp forests. 'I think we didn't really appreciate how important they were until we lost them,' Prentice said, describing the orange, purple or brown sunflower stars as a 'keystone' species with an outsized impact on their ecosystem. The giant sea stars are top predators, striking fear into other invertebrates. 'Almost everything that lives on the ground underwater runs away from them when they're coming,' said Gehman, a marine disease ecologist at the Hakai Institute and an adjunct professor at the University of B.C.'s Institute of Oceans and Fisheries. They keep sea urchin populations in check, in turn ensuring the health of help forests that provide habitat and food for numerous other species. The devastation of the sunflower sea stars has caused a 'total ecosystem shift,' Prentice said, transforming biodiverse kelp forests into 'urchin barrens.' The bacterium that causes sea star wasting disease had remained elusive for more than a decade since sea stars were first observed dying in large numbers in 2013. The same bacterium has been known to attack scallop larvae. Prentice said the breakthrough came after the research team switched from examining diseased tissues to focusing on the sea stars' coelomic fluid, likening it to the blood of the sea star. Earlier research had involved running the tissues through tiny membrane filters that would have excluded bacteria, which are typically larger than viruses, she explained. The Hakai Institute team started by replicating the initial experiments, but they weren't able to cause disease in healthy sea stars, she said. 'We were doing everything we could and we were just never ever able to cause disease, and so to us that suggested that the pathogen is larger than a virus.' However, after pivoting to coelomic fluid, which Prentice described as 'essentially sea water,' the researchers did trigger disease in healthy sea stars. 'That suggested that the pathogen was in that fluid, and so then we just end up working with a much cleaner, easier tissue type to investigate,' she said. From there, Prentice created a list of all the different microbial species found in wasting sea stars and compare it against the healthy stars in the lab. 'I finally got to a place where I generated these different lists and it was very evident right away that there (were) tons of different Vibrio species within our wasting sea stars and we weren't really seeing that in our healthy sea stars,' she said. Prentice said she then filtered the genetic data to look at each strain of Vibrio bacteria, which led to their eureka moment with Vibrio pectenicida. 'We just saw it in every single wasting sea star sample, and then we looked at our controls and it was just not in any of them,' she said. Prentice said other researchers had wished her 'good luck' when she joined the project, but there was skepticism over whether they would solve the mystery. It felt 'incredible' to be part of a discovery that could help make a meaningful difference in the recovery of sea stars and their ecosystems, she said. Gehman, too, said she wasn't sure the project would result in a singular answer. 'I thought it would be complicated. I thought there would be multiple things relying on other things,' she said. 'This was much clearer than I was expecting.' The discovery allows researchers to turn their efforts to deeper questions, including the possible role of warming ocean temperatures and the potential to breed sea stars in captivity to promote disease resistance and spur recovery, she said. The disease now appears to be seasonal, with outbreaks occurring in the warmer months, suggesting temperature may be a factor, said Gehman, adding she will soon conduct temperature experiments to investigate further. 'Does Vibrio pectenicida grow faster at warmer temperatures and the sea star can sort of survive at the growth rates at cooler temperatures, but when you get to warmer temperatures, they can't, is that what's happening?' The findings could help researchers understand where sea stars may struggle or survive with climate change in the future, Gehman said. Prentice said there are 'remnant' populations of sunflower stars along the B.C. coast, and its 'very possible' some could be more resistant to the wasting disease. She said finding and selectively breeding sea stars with a higher capacity to fight off the disease could produce 'superstar' sea stars for reintroduction in the wild. 'It seems like science fiction sometimes, but people are working on it,' she said. This report by The Canadian Press was first published Aug. 4, 2025.
Time of India
27-06-2025
- Science
- Time of India
Why hundreds of birds may go extinct in the next coming years
Birds enrich our world with their vibrant colors, and movements, playing crucial roles in pollination, pest control, and seed dispersal. However, a recent study warns that climate change and habitat destruction are putting global bird diversity at risk. The potential loss of unique species like the bare-necked umbrellabird and helmeted hornbill could severely impact ecosystems. Projections suggest that up to 250 bird species may disappear, even with conservation efforts, with some being too vulnerable to survive without direct intervention. How climate and hunting threaten global bird diversity According to a recent study published in the journal Nature Ecology & Evolution analysing nearly 10,000 bird species found that birds are particularly vulnerable due to hunting pressure and climate stress. Birds with broad wings, often found in forests, are especially threatened by habitat destruction. The expected loss of these species could lead to a 3.2% decline in global bird functional diversity over the next century, which may seem small but would have significant ecosystem impacts. Large, unique birds often play irreplaceable roles, and their disappearance would leave gaps that other birds cannot fill, ultimately damaging the ecosystem balance. Why do hundreds of birds need more than just a safer habitat Researchers found that even in the best-case scenario, where all human threats are eliminated, around 250 species would still face extinction. This accounts for nearly half of the projected losses, highlighting that some species are too vulnerable to survive without targeted conservation efforts. Birds like the Cebu flowerpecker, with fewer than 70 individuals remaining, may require specific interventions like habitat restoration or captive breeding to prevent their disappearance. The study emphasizes that reducing threats alone is insufficient, as past damage and small, isolated populations continue to pose significant risks. Addressing specific threats to the unique birds Habitat loss affects over 1,600 bird species, but other threats like hunting and accidental deaths have a greater impact on preserving unique bird traits. Reducing these specific threats can be more effective in conserving rare bird features, even if it doesn't save as many species overall. Certain birds, such as those with long tails and short beaks, are more vulnerable to hunting, and those with broad wings are more affected by habitat destruction. This insight can inform targeted conservation efforts. Protecting birds that shape our ecosystem With 100 functionally unique species protected, over two-thirds of the global functional diversity of birds could be protected. These species, like nectar-feeders or seed dispersers, serve vital ecological roles with unique characteristics. Certainly, by saving around 37 of those, we could achieve this - since 1993, 21-32 have already been protected. This might be successful with a few years of dedicated conservation. Also read | The world's richest man in history was wealthier than any billionaire today
