Latest news with #AlyssaGehman
Economic Times
4 days ago
- Science
- Economic Times
Death of 5 billion sea stars mystery solved: Scientists reveal what killed the iconic star-shaped creatures
Scientists say they have finally discovered the cause behind the death of more than 5 billion sea stars along the Pacific coast of North America, solving a mystery that has lasted over a decade. As per an AP report, starting in 2013, a mysterious disease called sea star wasting disease led to a massive die-off of sea stars (often called starfish), from Mexico to Alaska. More than 20 species were affected, with the sunflower sea star hit hardest, losing nearly 90% of its population in just five years. 'It's really quite gruesome,' said Alyssa Gehman, a marine disease expert at the Hakai Institute in British Columbia, who worked on the new research. 'Healthy sea stars have puffy arms sticking straight out, but with the disease, they develop lesions and then their arms actually fall off.' The cause? A bacteria known as Vibrio pectenicida, the same type that also affects shellfish, was identified in a new study published in the journal Nature Ecology and Evolution. 'This solves a long-standing question about a very serious disease in the ocean,' said Rebecca Vega Thurber, a marine microbiologist at the University of California, Santa Barbara, who was not part of the study. For years, scientists believed the cause might be a virus, particularly a densovirus. But further research revealed that this virus exists in healthy sea stars too, and wasn't responsible for the had also missed the real cause earlier because they mainly studied dead sea stars, which no longer had the internal fluid needed for proper analysis. This time, scientists focused on coelomic fluid, the liquid inside living sea stars, and found the harmful bacteria there.'It's incredibly difficult to trace the source of environmental diseases, especially underwater,' said microbiologist Blake Ushijima from the University of North Carolina, who wasn't involved in the study. He called the research 'really smart and significant.'Now that the cause is known, scientists believe they can start efforts to protect and restore sea star to Melanie Prentice, co-author of the study, researchers can now test which sea stars are still healthy, explore breeding in captivity, and move healthy individuals to areas where the population has collapsed. They may also test whether some sea stars have natural immunity, and whether probiotics could help protect work is essential not just for the sea stars, but for the entire marine ecosystem. Sunflower sea stars are known for eating sea urchins, which helps keep their numbers in check. Since the sea stars have vanished, sea urchins have taken over, destroying about 95% of kelp forests in Northern California within ten years. These kelp forests are often called the 'rainforests of the ocean,' and they provide food and shelter for fish, sea otters, seals, and many other marine species. 'Sunflower sea stars look sort of innocent when you see them,' said Gehman, 'but they eat almost everything that lives on the bottom of the ocean. They're voracious eaters.'Now, with this new breakthrough, scientists hope to bring sea star numbers back, and help restore the Pacific's kelp forests. Inputs from AP
Time of India
5 days ago
- Health
- Time of India
What led to the death of billions of starfish in over a decade? Scientists might finally have the answer
After more than ten years of searching, scientists say they have finally solved the mystery behind a catastrophic epidemic that wiped out over five billion sea stars along the Pacific coast of North America. A newly identified bacterium is believed to be responsible, marking a breakthrough in efforts to save these iconic marine animals. Since 2013, a rapidly spreading illness known as sea star wasting disease has caused massive die-offs from Mexico to Alaska, affecting more than 20 different species. The sunflower sea star was among the worst hit, its population declined by about 90% within the first five years of the outbreak. 'It's really quite gruesome,' said Alyssa Gehman, a marine disease ecologist at the Hakai Institute in British Columbia, Canada, who helped identify the cause. She described how healthy sea stars usually have 'puffy arms sticking straight out,' but once infected, they develop lesions and eventually 'their arms actually fall off.' The answer, finally published in the journal Nature Ecology and Evolution, points to a bacterium, Vibrio pectenicida, which is also known to infect shellfish. by Taboola by Taboola Sponsored Links Sponsored Links Promoted Links Promoted Links You May Like Become Fluent in Any Language Talkpal AI Undo The findings represent 'a long-standing question about a very serious disease in the ocean,' said Rebecca Vega Thurber, a marine microbiologist at the University of California, Santa Barbara, who was not part of the study. Identifying the true culprit wasn't easy. According to Melanie Prentice of the Hakai Institute, a co-author of the study, earlier efforts were misled by a densovirus, which researchers initially thought was the cause. That virus, however, turned out to be a normal resident of healthy sea stars. Another problem with previous studies was that they often used tissue samples from dead sea stars, which no longer contained coelomic fluid, the bodily fluid surrounding internal organs where the disease agent would be active. This latest research took a different approach. Scientists focused on analysing that specific coelomic fluid, and it was there that they discovered the bacterium Vibrio pectenicida. Blake Ushijima, a microbiologist at the University of North Carolina, Wilmington, who was not involved in the study, praised the team's 'really smart and significant' detective work. He acknowledged the unique challenge of identifying marine pathogens, saying it is 'immensely difficult' to trace environmental disease sources, 'especially underwater.' Now that the root cause has been pinpointed, scientists hope they can act to prevent further losses. Prentice said researchers might now begin testing the remaining sea stars for overall health. They're also considering captive breeding or relocating healthy individuals to regions where sunflower sea stars have disappeared. Scientists are also exploring whether certain populations may have natural immunity, or whether treatments such as probiotics could help strengthen resistance to the disease. The stakes go far beyond just the sea stars themselves. These creatures are key predators in kelp forest ecosystems. Their disappearance has led to ripple effects throughout the food web, as kelp forests provide shelter and food for fish, sea otters, and seals. Restoring sea star populations could help regrow what Thurber described as 'the rainforests of the ocean.'
USA Today
5 days ago
- Health
- USA Today
Scientists identify culprit killing sea stars in the Pacific Ocean
Sick sea stars are lethargic, lose their arms and disintegrate into gooey masses. More than 90% of sunflower sea stars were killed. More than a decade after a mysterious sickness began killing billions of sea stars off the Pacific Coast, scientists say they've identified the bacteria that causes the deadly disease. A team of at least 15 scientists from a half-dozen organizations collaborated on the research, hoping to figure out what had killed the sea stars. Solving that riddle would allow work to begin on recovering the species and the ecosystems harmed by their decline. After four years of testing the creatures and scrutinizing the results of their DNA analyses, the researchers found a bacteria always present on the sick sea stars that wasn't on healthy ones. The study raises hopes for a brighter future for sea stars, for potential treatments and for possibly restoring the kelp forests that relied on them to keep sea urchins under control, said two of its co-authors, Melanie Prentice and Alyssa Gehman, colleagues at the Hakai Institute in British Columbia and the University of British Columbia. The study announcing the project's results was published Aug. 4 in the journal 'Nature Ecoloy and Evolution.' Although most people think of the star-shaped animals as starfish, and some of them are even named starfish, scientists call them 'sea stars' because they're not fish. They're a group of animals, including sea cucumbers and sea urchins, called echinoderms. What happened to sea stars? From a tide pool in Olympic National Park, along the Pacific coast of Washington state, the first case of sea star disease was reported in June 2013. Soon, sea stars fell ill in Sitka, Alaska, then off the coast of British Columbia and San Diego, and eventually as far south as Mexico. Sea stars that contracted the disease became lethargic, developed lesions, lost their arms and disintegrated into gooey masses within days, according to the National Oceanic and Atmospheric Administration. The pathogen could kill a healthy group of sea stars in 24 hours, USA TODAY reported in 2013. Between 2013 and 2017, the pathogen killed more than 90% of sunflower sea stars in one of the largest marine wildlife disease outbreaks on record, NOAA concluded. These sea stars can measure more than 3 feet from tip to tip and appear in a range of colors. Once one of the more abundant and recognizable members of the sea star family on the Pacific coast, sunflower sea star populations plummeted offshore south of Washington State and disappeared almost entirely from the coast of Southern California. Although they are the most susceptible to the pathogen, the disease has been identified in more than 20 sea star species. Vast kelp forests in the ocean also suffered, because it turns out the sea stars were helping to control the voracious sea urchins that, left unchecked, decimated the kelp. What did the researchers do? A large group of researchers met in February 2020, just before the COVID-19 pandemic gripped the planet, and strategized on the science necessary to try and recover sunflower sea stars, said Prentice and Gehman, in a joint interview with USA TODAY. Their meeting and subsequent collaboration also included The Nature Conservancy, the Tula Foundation, and researchers from the University of Washington and the U.S. Geological Survey. The scientists collected wild sunflower sea stars in at least six locations in British Columbia and Washington between 2021 and 2024, then conducted a set of controlled experiments. In a fluke of history, the scientists were working to stop the spread of a deadly virus in sea stars at the same time the world was dealing with the pandemic. As they were quarantining sea stars they had collected from the wild, team members who traveled were quarantining and isolating themselves to prevent the spread of COVID-19. Sea star mystery unveiled Was there ever an "aha" moment? Yes, Prentice said. One day, she was looking at data on microbes they'd collected from healthy sea stars and comparing them to data sets of microbes from wasting sea stars. Just as she was about to walk into a meeting with Gehman and Grace Crandall, another colleague and study co-author, she noticed there were 'tons' of vibrio pathogens in the ailing sea stars. In their meeting, she opened her computer, showing Gehman and Crandall what she'd learned, and they started breaking down the genetic sequences of the vibrio they were seeing. The culprit was identified as Vibrio pectenicida. "It was apparent immediately that it was in all of our wasting samples and none of our healthy samples," Prentice said. They spent another year, working to back up their conclusions and kept getting more evidence that it was the pathogen causing the disease. What is vibrio? Vibrio is one of a vast array of species in the marine environment, and many are known to be pathogens. One kind of vibrio kills oysters and can be deadly to people, commonly referred to as 'flesh-eating" bacteria. Another causes cholera. One thing that was particularly shocking about their moment of discovery, said Gehman, was that the group of scientists had assumed finding the answer would be complicated. 'It turns out that the pattern was visual and we could really see it," she said. "That was surprising, and was the moment we realized we might be able to solve this question." Kevin Lafferty, a marine disease ecologist and senior scientist with the U.S. Geological Survey, who was not a part of the study group, wrote a companion piece in the journal lauding the group's work. "The research is really amazing and took so much careful, hard work," Lafferty told USA TODAY. Marine diseases can be difficult to diagnose "we just don't have a lot of expertise in marine disease. "That's a huge handicap and they overcame that with a lot of hard work and modern molecular tools," he said. "The fact that you can take an eyedropper of sea water and identify 100 species of bacteria is a huge leap forward for understanding microbial diseases, especially in the water." What happens now for sea stars? This discovery "opens up a door that wasn't available to us because we didn't know what was causing the disease," Gehman said. "There's a lot of people who are trying to save this species," she said. "There's a lot of work that can immediately take advantage of what we are doing." Researchers already are working on a diagnostic test akin to a COVID test that could be 'really important' for testing sea stars and the water when they consider transplanting sea stars to try to recover populations, Prentice said. 'It's going to be really, really helpful in the way we think about managing the species.' Questions remain, wrote Lafferty, the USGS scientist. The origin of the pathogen is unknown, he said. Could it be transmitted from the mollusks that sea stars eat, the way people get sick after eating oysters infected with a vibrio pathogen? Could it be transmitted from sea star to sea star or spread through aquaculture? These questions and more are expected to be part of the future research possibilities now open. Because there are remnant healthy populations of sea stars in Alaska and British Columbia, and a few in Washington, armed with the information that identifies the disease, Gehman and Prentice said researchers hope to be able to bring some of the healthy sea stars into captive breeding programs to raise animals that can resist the pathogen. Other possibilities include finding a probiotic that could help sea stars fight off disease, similar to a method scientists use to pretreat some corals, or identifying a naturally occurring marine virus that only attacks specific kinds of bacteria, such as the virus that researchers are using to help recover abalone populations off the southern California coast. 'Hopefully one day we'll actually be out planting sea stars back into the wild where we've lost them," Prentice said. Contributing: Elizabeth Weise, USA TODAY
Yahoo
5 days ago
- Health
- Yahoo
Scientists say they have solved the mystery of what killed more than 5 billion sea stars
Sea Star Disease WASHINGTON (AP) — Scientists say they have at last solved the mystery of what killed more than 5 billion sea stars off the Pacific coast of North America in a decade-long epidemic. Sea stars – often known as starfish – typically have five arms and some species sport up to 24 arms. They range in color from solid orange to tapestries of orange, purple, brown and green. Starting in 2013, a mysterious sea star wasting disease sparked a mass die-off from Mexico to Alaska. The epidemic has devastated more than 20 species and continues today. Worst hit was a species called the sunflower sea star, which lost around 90% of its population in the outbreak's first five years. 'It's really quite gruesome,' said marine disease ecologist Alyssa Gehman at the Hakai Institute in British Columbia, Canada, who helped pinpoint the cause. Healthy sea stars have 'puffy arms sticking straight out,' she said. But the wasting disease causes them to grow lesions and 'then their arms actually fall off.' The culprit? Bacteria that has also infected shellfish, according to a study published Monday in the journal Nature Ecology and Evolution. The findings 'solve a long-standing question about a very serious disease in the ocean," said Rebecca Vega Thurber, a marine microbiologist at University of California, Santa Barbara, who was not involved in the study. It took more than a decade for researchers to identify the cause of the disease, with many false leads and twists and turns along the way. Early research hinted the cause might be a virus, but it turned out the densovirus that scientists initially focused on was actually a normal resident inside healthy sea stars and not associated with disease, said Melanie Prentice of the Hakai Institute, co-author of the new study. Other efforts missed the real killer because researchers studied tissue samples of dead sea stars that no longer contained the bodily fluid that surrounds the organs. But the latest study includes detailed analysis of this fluid, called coelomic fluid, where the bacteria Vibrio pectenicida were found. 'It's incredibly difficult to trace the source of so many environmental diseases, especially underwater,' said microbiologist Blake Ushijima of the University of North Carolina, Wilmington, who was not involved in the research. He said the detective work by this team was 'really smart and significant.' Now that scientists know the cause, they have a better shot at intervening to help sea stars. Prentice said that scientists could potentially now test which of the remaining sea stars are still healthy — and consider whether to relocate them, or breed them in captivity to later transplant them to areas that have lost almost all their sunflower sea stars. Scientists may also test if some populations have natural immunity, and if treatments like probiotics may help boost immunity to the disease. Such recovery work is not only important for sea stars, but for entire Pacific ecosystems because healthy starfish gobble up excess sea urchins, researchers say. Sunflower sea stars 'look sort of innocent when you see them, but they eat almost everything that lives on the bottom of the ocean,' said Gehman. 'They're voracious eaters.' With many fewer sea stars, the sea urchins that they usually munch on exploded in population – and in turn gobbled up around 95% of the kelp forest s in Northern California within a decade. These kelp forests provide food and habitat for a wide variety of animals including fish, sea otters and seals. Researchers hope the new findings will allow them to restore sea star populations -- and regrow the kelp forests that Thurber compares to 'the rainforests of the ocean.' ___ The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute's Department of Science Education and the Robert Wood Johnson Foundation. The AP is solely responsible for all content.
1News
6 days ago
- Health
- 1News
Scientists say they have solved the mystery of what killed more than 5 billion starfish
Scientists say they have at last solved the mystery of what killed more than 5 billion sea stars off the Pacific coast of North America in a decade-long epidemic. Sea stars – often known as starfish – typically have five arms and some species sport up to 24 arms. They range in colour from solid orange to tapestries of orange, purple, brown and green. Starting in 2013, a mysterious sea star wasting disease sparked a mass die-off from Mexico to Alaska. The epidemic has devastated more than 20 species and continues today. Worst hit was a species called the sunflower sea star, which lost around 90% of its population in the outbreak's first five years. 'It's really quite gruesome,' said marine disease ecologist Alyssa Gehman at the Hakai Institute in British Columbia, Canada, who helped pinpoint the cause. Healthy sea stars have 'puffy arms sticking straight out', she said. But the wasting disease causes them to grow lesions and 'then their arms actually fall off'. ADVERTISEMENT A sunflower sea star is reduced to goo by sea star wasting disease at Calvert Island, British Columbia, Canada, in 2015. (Source: Grant Callegari/Hakai Institute via AP) The culprit? Bacteria that has also infected shellfish, according to a study published today in the journal Nature Ecology and Evolution. The findings 'solve a long-standing question about a very serious disease in the ocean", said Rebecca Vega Thurber, a marine microbiologist at University of California, Santa Barbara, who was not involved in the study. It took more than a decade for researchers to identify the cause of the disease, with many false leads and twists and turns along the way. Early research hinted the cause might be a virus, but it turned out the densovirus that scientists initially focused on was actually a normal resident inside healthy sea stars and not associated with disease, said Melanie Prentice of the Hakai Institute, co-author of the new study. Other efforts missed the real killer because researchers studied tissue samples of dead sea stars that no longer contained the bodily fluid that surrounds the organs. But the latest study includes detailed analysis of this fluid, called coelomic fluid, where the bacteria Vibrio pectenicida were found. ADVERTISEMENT 'It's incredibly difficult to trace the source of so many environmental diseases, especially underwater,' said microbiologist Blake Ushijima of the University of North Carolina, Wilmington, who was not involved in the research. He said the detective work by this team was 'really smart and significant'. Healthy populations of sunflower sea stars are found in the Knight Inlet fjord of the Central Coast of British Columbia, Canada, in 2023. (Grant Callegari) Now that scientists know the cause, they have a better shot at intervening to help sea stars. Prentice said that scientists could potentially now test which of the remaining sea stars are still healthy — and consider whether to relocate them, or breed them in captivity to later transplant them to areas that have lost almost all their sunflower sea stars. Scientists may also test if some populations have natural immunity, and if treatments like probiotics may help boost immunity to the disease. Such recovery work is not only important for sea stars, but for entire Pacific ecosystems because healthy starfish gobble up excess sea urchins, researchers say. With a lack of predatory sunflower sea stars, sea urchins proliferate in Hakai Pass, British Columbia, Canada, in 2019. (Source: Grant Callegari/Hakai Institute via AP) ADVERTISEMENT Sunflower sea stars 'look sort of innocent when you see them, but they eat almost everything that lives on the bottom of the ocean', said Gehman. 'They're voracious eaters.' With many fewer sea stars, the sea urchins that they usually munch on exploded in population – and in turn gobbled up around 95% of the kelp forest s in Northern California within a decade. These kelp forests provide food and habitat for a wide variety of animals including fish, sea otters and seals. Researchers hope the new findings will allow them to restore sea star populations – and regrow the kelp forests that Thurber compares to 'the rainforests of the ocean'.
