Scientists have identified a substance that enables some sharks to give off a bright green glow, which they believe only other sharks can see.
The authors of the paper, published in the journal iScience, previously showed that swell sharks—who live in California’s Monterey Bay to southern Mexico and the coast of Chile—are biofluorescent. That means they soak up light—in this case ambient blue ocean light—and use it to give off light in a different color, usually green, red or orange.
In their latest study, researchers wanted to learn more about what being biofluorescent means for these creatures. They looked at the swell shark, as well as the chain catshark that inhabits the western Atlantic ocean.
Past studies have shown the lighter beige parts of the species have a higher intensity of green fluorescence, compared with the darker areas.
Now, by testing the dark and light patches, the team found a group of small molecule metabolites in the lighter skin. What are known as brominated tryptophan-kynurenine small-molecule metabolites are different to the green fluorescent proteins used by biofluorescent creatures like jellyfish and corals.
Study co-author David Gruber, professor at City University of New York, told Newsweek: “I was surprised that the biofluorescence in sharks was so chemically different from the other forms previously discovered.”
As well as giving sharks their glow, the metabolites also appear to have other jobs, like fighting infection, and finding one another in the ocean.
Jason Crawford, a professor at Yale University who co-authored the work, explained in a statement: “Imagine if I were bright green, but only you could see me as being bright green, but others could not.”
He explained: “It’s a completely different system for them to see each other that other animals cannot necessarily tap into. They have a completely different view of the world that they’re in because of these biofluorescent properties that their skin exhibits and their eyes can detect.”
“This study opens new questions related to potential function of biofluorescence in central nervous system signaling, resilience to microbial infections and photoprotection,” said Gruber.
The team hopes the findings could be used to create new imaging techniques, which could be used in scientific research or medicine.
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Fuente: / Source: www.newsweek.com