Washington – scientists claim to have resolved the mystery of the death of more than 5,000 million sea stars on the Pacific coast of North America during an epidemic that lasted a decade.
Sea stars, which usually have five arms, and some species up to 24, vary in color from solid orange to orange, purple, brown and green tapestries.
As of 2013, a mysterious wear disease of sea stars caused a massive death from Mexico to Alaska. The epidemic has devastated more than 20 species and continues today. The most affected was a species called Sunflower Sea star, which lost about 90% of its population in the first five years of the outbreak.
“It’s really quite frightening”Said Marina Gehman’s ecologist from the Hakai Institute in British Columbia, Canada, who helped identify the cause.
The healthy sea stars have “swollen arms that stand out straight,” he said. But wear disease causes them to grow injuries and “then their arms fall.”
The culprit? A bacterium that has also infected seafood, 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 the University of California, Santa Barbara, who did not participate in the study.
The first studies pointed out that the cause could be a virus, but it turned out that the densevirus in which the scientists initially focused was actually a normal resident within the healthy sea stars and was not associated with the disease, said Melanie Prentice of the Hakai Institute, co -author of the new study.
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Other efforts ignored the true murderer because the investigators studied samples of dead stars fabric that no longer contained the body fluid surrounding the organs.
But the last study includes a detailed analysis of this fluid, called celomic fluid, where the pecttenicidal vibrio bacteria were found.
“It’s incredibly difficult to track the source of so many environmental diseases, especially under water.”Said the microbiologist Blake Ushijima of the University of North Carolina, Wilmington, who did not participate in the investigation. He said that the detective’s work of this team was “really intelligent and significant.”
Now that scientists know the cause, they have a better opportunity to intervene to help sea stars.
Prentice said that scientists could now potentially prove which of the remaining sea stars are still healthy and consider whether to relocate or raise them in captivity and then transplant them to areas that have lost almost all their sunflower sea stars.
Scientists can also prove if some populations have natural immunity and if treatments such as probiotics can help increase immunity to disease.
Such recovery work is not only important for sea stars, but for whole peaceful ecosystems because healthy sea stars devour excess sea urchin, researchers say.
Sunflower sea stars “They seem innocent when you see them, but they eat almost everything that lives at the bottom of the ocean”Said Gehman. “They are voracious dining rooms.”
With many less sea stars, sea urchins that usually eat exploded in the population and, in turn, devoured around 95% of sea seaweed forests in northern California in a decade. These seaweed forests provide food and habitat for a wide variety of animals, including fish, marine otters and seals.
Researchers expect the new findings to allow them to restore seafood populations and grow seaweed forests that Thurber compares with “the tropical jungles of the ocean.”
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