Man's favorite creature of the ocean – we rejoice every time we catch a glimpse of them leaping from the water to the sky. Oh, the fascinating dolphins, they're dying.
After Hurricane Katrina in 2005, a mysterious skin disease emerged among dolphins off the waters off New Orleans. Now scientists have officially determined its cause.
"Freshwater skin disease" has afflicted coastal cetaceans around the world for more than a decade, producing severe lesions that cover most of the body.
Previously, scientists had never found a cause, but now we have a grim explanation: changes in the environment and climate.
Pádraig Duignan, chief pathologist at the Marine Mammal Center in Sausarito, Calif., said: "Devastating skin diseases have been killing dolphins since Hurricane Katrina and we are delighted to have finally found the crux of the problem. ”
"But sadly, due to this year's record hurricane season in the Gulf of Mexico, and at the same time, due to climate change, the storms on a global scale have become more intense, and it can be expected that dolphins will have explosive deaths."
Although first seen in the United States, two dolphin deaths in Australia in 2007 and 2009 provided scientists with key clues.
The autopsy report pointed to the water environment.
After hurricanes and tornadoes, outbreaks of freshwater skin disease in cetaceans followed. The hurricane brings a lot of rainwater into rivers and coastal waters. They rapidly reduce the salinity of nearby seawater, creating salinization conditions. Environmental monitoring data from Australian sites suggests that this can last for weeks or months.
Dolphins can tolerate it for a while, but prolonged exposure to fresh water can cause a series of changes in the chemical composition of the animal's skin and blood, creating dermatitis, lesions and other physiological stresses, and reducing resistance leads to algae, diatoms, fungi and bacteria attaching to the skin.
"The rupture of the skin causes the dolphins to lose vital ions and proteins from their bodies... Fresh water pours in, causing swelling and ulceration. ”
"These injuries are equivalent to third-degree burns in humans, which are very terrible injuries that can lead to death very quickly." Electrolyte components in the [dolphin] bloodstream change, eventually leading to organ failure. ”
Worse still, the researchers note, the frequency of severe weather events such as floods, storms and hurricanes is expected to increase under the influence of climate change.
"If it continues to deteriorate, we may lose them and dolphins will become a historical concept."
The findings are reported in Scientific Reports.
https://www.sciencealert.com/fatal-skin-disease-afflicting-dolphins-worldwide-linked-to-climate-change-study-finds