Latest news with #NatureEcologyandEvolution
Economic Times
3 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
3 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.'
1News
4 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'.
4 days ago
- Health
After a decade of death, Canadian scientists say they've found the sea star killer
Scientists say they have found the cause behind the disease that turns vibrant, 24-armed sea stars into puddles of goo. Melanie Prentice, a research scientist at the Hakai Institute, is part of a team that has spent years investigating the cause of this disease. Their research was published on Monday in the journal Nature Ecology and Evolution (new window) . "The agent is a bacteria. It's called Vibrio pectinicida ," Prentice told CBC News. After a decade of these creatures being pushed to the brink of extinction, experts say this is the first step in a road to recovery, not just for this species, but for a critical support in humanity's defence against climate change. Twisted arms that walk away The most affected species are sunflower sea stars, which once boasted a range along the west coast of North America, from Baja California to Alaska. Then, in 2013, a mass die-off occurred from sea star wasting disease. Enlarge image (new window) Alyssa Gehman is seen diving in in the Burke Channel, one of the fiords along B.C.'s Central Coast. She is making notes on sea stars there. Photo: Bennett Whitnell/Hakai Institute And it's a gruesome end. Their arms kind of twist back on themselves, so they get kind of into puzzle pieces, said Alyssa Gehman, a marine disease ecologist who is also part of the Hakai Institute research team. They then tend to lose their arms, and then, their arms will sort of walk away from their bodies. Soon after, Gehman says that lesions form and the sea stars dissolve and die. The paper estimates that more than 87 per cent of sunflower sea stars in northern parts of the west coast have been killed. In the southern habitat ranges, the species is considered functionally extinct. When it first happened, it was just fields and fields of puddles of dying sea star goo, said Sara Hamilton, science co-ordinator for the Oregon Kelp Alliance. Hamilton was not involved in the research. It was like something out of a horror movie. The hunt for the star killer Multiple theories identifying the cause either didn't pan out or were disproven. What the team did in this case was take healthy sea stars into the lab and expose them to infection. They did this over several years to try and isolate the cause. Enlarge image (new window) A wasting sunflower sea star off Calvert Island in B.C. Photo: Grant Callegari/Hakai Institute Gehman explained the process: We take body fluid or tissue from a sick star and then we put that experimentally into other sea stars that we know are healthy. The paper's result was that 92 per cent of these exposures worked in transmitting the disease to the healthy star — killing it within 20 days. These experiments also revealed that Vibrio pectinicida was the most likely culprit. Experts are impressed with the paper's diligence and effort. They didn't just stop when they found one level of evidence — they went and found a second level of evidence and a third level of evidence, said Hamilton, from Oregon Kelp Alliance. Amanda Bates, ocean conservation professor at the University of Victoria, also said there's a pathway — essentially that you isolate disease agents and link them to being a cause of an outbreak — and this research team followed those processes perfectly. Hope for recovery Knowing the cause provides hope for restoration efforts, experts say. Now we can go out and actually do tests and see the actual prevalence of this pathogen in the field, said Gehman. Furthermore, any captive breeding programs that are trying to restore sea star populations can now screen and test those populations before putting them back into a risky environment. Enlarge image (new window) Melanie Prentice, a research scientist at the Hakai Institute, is part of a team that has spent years investigating the cause of the sea star wasting disease. Photo: Bennett Whitnell/Hakai Institute Hamilton agrees. That's one of the things we're most worried about with some of these recovery efforts, she said. If we do captive breeding and outplant, we certainly don't want to introduce … a new outbreak of the disease. The lost decade Bates, who has seen this disease as far back as 2009, is cautious about the rush to recovery. While we know disease impacts us as humans, I think we often forget that it impacts wildlife, she told CBC News. "We're a decade on since that really big mass mortality event, and we still don't have pycnopodia [sunflower sea stars] recovering in many places." Hamilton said the reintroduction of sunflower sea stars will be valuable because of what their absence has meant for ecosystems. Sea urchin populations have gone up — which also means kelp forests have been decimated. Urchins are kind of like the goats of the ocean, she said. They'll eat anything, they just mow things down. Enlarge image (new window) A sunflower sea star in the Burke Channel, one of the fiords along B.C.'s Central Coast. The species eats sea urchins, which have been blamed for eating kelp forests along the coast and causing ripple effects along the food chain. Photo: Grant Callegari/Hakai Institute Restoring the sea star means kelp forests might once again thrive. This will likely mean improvements to biodiversity, food, tourism as well as serve as coastline defences against erosion and storms supercharged by climate change. It's definitely our ally in the climate crisis, Prentice said. I think when we're talking about sea star wasting disease, we're not just talking about the sea star species — which we love in their own right — but entire marine ecosystems that have collapsed because of this epidemic. Bridget Stringer-Holden (new window) · CBC News Bridget Stringer-Holden is a 2024 Joan Donaldson CBC News Scholar, currently working as an associate producer. She graduated from UBC's Master of Journalism program and is passionate about science and climate reporting. Her work has been featured in The Globe and Mail, Vancouver Magazine, B.C. Business, The Vancouver Sun, The Georgia Straight and a variety of student papers, podcasts and radio stations. You can reach her at
Newsweek
4 days ago
- Health
- Newsweek
Death of 5 Billion Starfish Baffled Scientists—Until Now
Based on facts, either observed and verified firsthand by the reporter, or reported and verified from knowledgeable sources. Newsweek AI is in beta. Translations may contain inaccuracies—please refer to the original content. Researchers have traced the devastating loss of more than 5 billion sea stars—known colloquially as starfish—along the Pacific coast of North America over the past decade to a bacterial culprit. The findings, published in Nature Ecology and Evolution, help explain an ecological crisis that saw sunflower sea star populations plunge by up to 90 percent from Alaska to Mexico since 2013, reshaping vital marine ecosystems in the U.S. and Canada. Why It Matters The mass die-off, driven by "sea star wasting disease," has had devastating ripple effects across Pacific coastal ecosystems, including those off the U.S. These predators, especially the sunflower sea star, help regulate sea urchin populations. Their disappearance led to unchecked sea urchin growth, which in turn destroyed extensive kelp forests—habitats called the "rainforests of the ocean" due to their biodiversity and importance for marine mammals, fish, and invertebrates. In Northern California alone, kelp coverage dropped by 95 percent within a decade as a result. FILE - Starfish on the coast of Acadia National Park. FILE - Starfish on the coast of Acadia National Park. Edwin Remsberg/VWPics via AP Images What To Know In 2013, sea stars from Alaska to Mexico started exhibiting symptoms of "wasting syndrome"—including twisted limbs, lesions, and disintegration—that gradually devastated more than 20 species, with the sunflower sea star most affected. "It's really quite gruesome," said marine disease ecologist Alyssa Gehman from the Hakai Institute in British Columbia, Canada. The disease was so severe it often caused the sea stars' arms to detach entirely, added Gehman, who helped pinpoint its cause. Scientists had previously suspected a virus, but years of research showed that the densovirus found in dying sea stars was not the cause. Focus shifted after researchers analyzed the sea stars' coelomic fluid—their internal body fluid—and identified Vibrio pectenicida, a bacteria also known to infect shellfish, as the real culprit. In the lab, fluid from sick sea stars was injected into healthy counterparts, causing the wasting symptoms to recur. When the team heat-treated this fluid, killing the microbes, healthy sea stars did not develop disease—definitively pointing to a microbial origin. The bacteria was isolated and pure cultures were shown to cause the illness. The findings, achieved after more than a decade of setbacks, open the door for targeted conservation strategies. Marine microbiologist Rebecca Vega Thurber of UC Santa Barbara, who was not involved in the study, called it the solution to a "long-standing question about a very serious disease in the ocean." What People Are Saying Blake Ushijima, a microbiologist at University of North Carolina, Wilmington, praised the team's detective work, saying: "It's incredibly difficult to trace the source of so many environmental diseases, especially underwater." Drew Harvell, a researcher at Cornell University and University of Washington and study co-author, told The Washington Post: "It's personally incredibly fulfilling to me to have such a solid answer after all this time." Jason Hodin, a senior research scientist at the University of Washington and study co-author, said: "The lack of understanding what the disease is has really been a pretty major impediment to being able to move forward with all the kinds of restoration strategies that we'd like to be able to do." What Happens Next Scientists still aim to clarify how the bacterium spreads in the wild, whether it is native or introduced, and what influences—such as warming ocean temperatures—might fuel future outbreaks. This article contains reporting by The Associated Press
