He's been studying the endangered turtles for 12 years. The discovery that hawksbill turtles can biofluoresce came as a big surprise to Alexander Gaos, director of the Eastern Pacific Hawksbill Initiative. Gruber isn't sure whether the red patches might be caused by algae or are just something that develops as a turtle ages. Their shells also glowed green under blue light, but didn't show any red patches. Gruber wanted to see if other hawksbill turtles also glowed, so he visited a nearby turtle farm that raised young hawksbills. The footage has been posted online by National Geographic, which supports Gruber under its Emerging Explorers program. The turtle's fluorescent colours can't be easily seen during the day.

'It was a beautiful moment where we were able to kind of witness this for the first time.'Ī hawksbill sea turtle as it cruises over a reef just off the shore of Curacao. Gruber followed the turtle over to an overhang, and then it disappeared down the side of a cliff. The adult turtle's metre-wide shell had a glowing green pattern all over, with patches of glowing red. 'As I'm filming, this green and red spaceship of a turtle sails in front of my camera,' he recalled. He was about 20 metres below the surface and 40 minutes into his dive when he ran into something unexpected. While it's sometimes possible to see the fluorescent colours in daylight, filming at night with a blue light makes the biofluorescent animals glow much more distinctly, so that's what Gruber did. Glowing sharks light up underwater worldsīecause blue is the colour that travels best through water, most biofluorescent marine creatures absorb blue light and emit green, yellow or red.Gruber stumbled across the turtle while trying to film biofluorescent sharks at night off the Solomon Islands.

More recently, Gruber has helped discover more than 200 new species of biofluorescent fish.īut turtles 'really surprised us because it's a whole different group of animals,' he said of the discovery in late July during an expedition funded by the TBA21 Academy. The hawksbill sea turtle's glow is caused by biofluorescence, the ability of an organism to absorb light of one colour and use it to emit light of a different colour.ĭavid Gruber, a marine biologist at the City University of New York, said many marine creatures biofluoresce because there are advantages to being able to produce other colours in the ocean, where mostly only the blue colour from sunlight can penetrate to any depth: 'You're living in a one-colour world.' As I'm filming, this green and red spaceship of a turtle sails in front of my camera - David Gruber, marine biologistīiofluorescent sea creatures include invertebrates such as jellyfish, corals and shrimp. Scientists have discovered that a critically endangered sea turtle has an amazing ability never seen before in a reptile - it glows neon green and red when exposed to blue light.

Bioflouresent seaturtle