Ed Gullekson / Scientific Progress
The skin lesions are the first sign that something is wrong. Then the limbs are dropped and the body breaks down, falling on itself as it flows. In the end, what was once a sea star was just a locust at the bottom of the ocean.
Since 2013, starfish disease has destroyed so many stars along the Pacific coast that scientists say it is the largest disease epidemic ever recorded in wild marine animals. Where dozens of stars once existed, divers do not see anything now.
While the epidemic itself is a natural phenomenon (if it is particularly devastating), the new research suggests that climatic changes may have exacerbated deadly disease.
"What we think is that hot water anomalies have made these sea stars more susceptible to the disease that was already there," says Joe Gaydos, a California-based scientific director at the University of California, Davis Society, SeaDoc, and an author of today's study. in a magazine Scientific progress.
He and the co-authors analyzed data collected by divers and discovered that divers were less likely to see live marine stars when water temperatures were abnormally high.
"Thinking that the warmer temperature of water itself can cause animals to get the disease faster, or make them more sensitive, it's a blow of one to two," says Gaydos. "It's a bit disturbing."
Worldwide, the temperature of the world has to grow as the Earth warms up due to climate change caused by human activity.
The study did not investigate why warmer waters can make marine stars more susceptible to disease. The authors assume that a relatively simple animal immune system may be weaker when the sea stars are heated up.
The same data on diver's research also confirms the previous finding: the massive outbreak of the starfish launches the cascade of other ecosystem changes. The seagrass that the sea star usually eats is abandoned. The entire rocks that were once covered with sea stars are now covered with the jeeps.
Fishermen eat sea grass.
"We see these great wild deserts where the tongues passed and ate all the seaweed," says Gaydos. Kelpa forests, like forest forests, are where they live and feed different species.
"We have a higher biological diversity when we have more seafood, so a cascade is set up," he adds. "If you look at the land, it would almost be like cleaning the forest."
It is unclear whether the starfish population will recover in the coming years. Studies published last year suggest that some sea stars could survive the disease, offering hope that animals will return over time.