Millions of sea stars have died in an epidemic of a decade. Scientists say they now know why.

Scientists say that they have finally resolved the mystery of what killed more than 5 billion sea stars, often known as the sea star, in front of the Pacific coast of North America in an epidemic of a decade lasting.

As of 2013, a mysterious sea star disease wear It caused a massive death from Mexico to Alaska. The epidemic has devastated more than 20 species and continues today. The worst success was a species called Sunflowing sea starwhich lost about 90% of its population in the first five years of the outbreak.

“It is really quite horrible,” said the environmentalist of Marina Alyssa Gehman at the Hakai Institute in British Columbia, Canada, who helped identify the cause.

Healthy sea stars have “swollen arms that stand out,” he said. But waste disease causes injuries and “then their arms really fall.”

The culprit? Bacteria that have 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 from the University of California, Santa Barbara, who did not participate in the study.

Sea stars generally have five arms and some species look up to 24 arms. They go in solid orange color to orange, purple, brown and green tapestries.

“The symptoms of marine stars wear syndrome include abnormally twisted arms, white lesions, arms and body deflation, arms loss and body disintegration,” says the national parks service. “They die in the course of days or weeks.”

The researchers took more than a decade to identify the cause of the disease, with many false leads, turns and turns on the road.

Early research hinted 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.

Other efforts lost the true murderer because the investigators studied samples of stars of the Dead Sea 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 vibrio pecttenicide bacteria were found.

“It is incredibly difficult to track the source of so many environmental diseases, especially under water,” said 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. The International Union for the Conservation of Nature has listed the star of the Sunflower Sea as in critical danger.

Prentice said that scientists could now try which of the remaining sea stars are still healthy, and consider whether to relocate, or raise them in captivity to transplant them later to areas that have lost almost all their sunflower sea stars.

The study indicates that vibrio bacteria have been called “the microbial barometer of climate change” because species are more frequent in water temperatures. The authors say that a next important phase of the investigation will be to work on a better understanding of the relationship between the increase in temperatures of seawater and the wear disease of marine 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 the stars of the sea, but for the ecosystems of the entire Pacific because researchers say that sea urchins in excess of healthy sea.

Sunflower sea stars “look innocent when you see them, but eat almost everything that lives at the bottom of the ocean,” Gehman said. “They are voraz dining rooms.”

With many less sea stars, sea urchins that generally eat exploited in the population, and in turn, torn around 95% of sea seaweed forests in northern California in a decade. These sea algae forests provide food and habitat for a wide variety of animals, including fish, sea otters and seals.

Researchers expect the new findings to allow them to restore marine stars populations, and algae forests that compare with “the tropical jungles of the ocean” grow again.