January 28, 2022

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The world's largest glowing shark discovered in New Zealand |  Science and Ecology |  DW

The world’s largest glowing shark discovered in New Zealand | Science and Ecology | DW

Beneath the ocean, at a depth of 200 to 1,000 meters, there is only a small amount of sunlight. This area, called Twilight, is home to three species of sharks that are capable of emitting light in the dark.

There, in the depths of New Zealand’s waters, a six-foot-long stone shark glows in the dark, according to the scientific journal Frontiers, according to a scientific study published as “the largest glowing spine in the world known to date.” Marine science.

Research confirms for the first time that this stone shark (Dalatius lychea) and two other species that live in the depths of New Zealand waters (Edmopterus lucifer and Edmopterus granulosus) are already known and capable of producing visible light. By biochemical reactions.

Samples of these three species were captured by the New Zealand Institute for Water and Atmospheric Research (NIWA) in January 2020 during a voyage over water covering the Saddam Rice Ocean floor, which stretches 1,000 kilometers east of the country. .

Jerome Malfett, the lead author of the study and the first to confirm the presence of bioluminescent sharks in New Zealand, explained that the captured specimens emit blue-green light, which glows slowly and darkens.

“They glow in the dark, they do not shine,” explained the Belgian scientist, who had the rare opportunity to study these properties in newly captured specimens, the NIWA report said.

How does its bioluminescence work?

Bioluminescent animals have elements, photophores, which produce light. Most of them have this process controlled by the nervous system. But when a team of Belgian scientists examined the skins of captured sharks, they were surprised to find photophores, the only animals that control light production by hormones.

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Sharks, like other bioluminescent creatures, hunt their prey and produce light when breeding or in groups, as well as hiding themselves in a light environment to protect themselves from predators, the report added.

“It took us a year to figure out how to stimulate the organ of light because all the neurotransmitters failed,” says Mallefet, until they realize that the same hormone that triggers sleep in humans is melatonin, which stimulates light in sharks. : “Melatonin stimulates the production of light and the hormone alpha-MSH stops it and this is a very slow process.”

Malleffer estimates that 57 bioluminescent light can be generated from the 540 known species of sharks, most of which live in small parts of the ocean known as the “twilight zone” at depths of more than 200 meters.

“The existence of luminous organisms in this region (three types of sharks were found) is increasingly making it clear that light formation plays an important role in shaping our planet’s massive ecosystem,” this first experimental experiment.

Mallef’s research, along with his colleagues Laurent Ducatlet and Darren Stevens of the NIWA at Louvain Catholic University, will help to better understand deep-sea animals.

E (Elbice / eFay / Frontiers in Marine Science)