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Scientists are finding the deep dark mysterious ocean isn't quite so dark as originally thought. As this ScienCentral News video reports, scientists are marveling at an ocean full of glowing creatures.
Let There Be Light
For centuries, people have watched with fascination as stars twinkle overhead. A similar phenomenon exists in the ocean, where sailors have documented sea life doing some twinkling of its own. Now, scientists who study marine animals are deciphering the light show below us, studying a phenomenon called bioluminescence—the glow produced by chemicals inside an animal's body—that tips off marine biologists documenting concentrations of ocean life and how that life behaves.
Edie Widder creates the spy gadgets that gather data on bioluminescence. Her new camera, the Eye in the Sea, catches snatches of light made by marine creatures. Another instrument, the HIDEX BP, "tells us a lot about the distribution of animals in the ocean," says Widder, a marine biologist at Harbor Branch Oceanographic Institution in Fort Pierce, Florida. "And now we're using it to actually be able to identify the animals in the ocean by the type of light they produce."
Land lovers like glow-worms, fireflies and some fungi also create bioluminescence. But it's a bigger phenomenon in the sea, where between 80 to 90 percent of ocean creatures use light for everything from mating to fighting.
"In the ocean environment, away from shore, this is a very strange place in terms of our thinking 'cause there's no trees or bushes for animals to hide behind, and yet they have to do all the hide-and-seek that animals do on land," says Widder, whose work was featured in Discover Magazine. "Predators have to be able to sneak up on prey and prey have to be able to hide from predators."
A deep sea cucumber that can bioluminesce image: Harbor Branch Oceanographic Institution
Evolution helped solve this problem by luring ocean life into the sea's dark reach where it's harder for animals to locate prey. At the same time, lack of light makes communication there very difficult.
Enter bioluminescence. Much as traffic signals speak to watchful motorists, most marine life uses light to talk to each other, not always nicely. "Animals can spray their bioluminescent chemicals into the face of a predator, temporarily blinding that predator," Widder says.
So how does sea life jazz up the underwater world by mixing chemical cocktails that explode into bright light, sparks and flashes? Inside the animals, electrons revolve around an atom's nucleus, circling and circling until energized by heat. Then, the electrons are pushed to higher orbits by two chemicals—luciferase and luciferin. Luciferase stimulates luciferin, which in turn oxidizes. After the electrons reach up, they decay, producing a blue-green glow, though some animals glow red.
With ever an eye peeled on the marvel unfolding at sea, Widder spent ten years tinkering with cameras. She worked with limited funding to create the Eye in the Sea camera, which has come closest to hitting on ways to successfully measure bioluminescent activity in the ocean, making it a reliable undersea census taker. Widder rigged the gadget to turn on when glowing sea creatures approach. The glow turns on a far red light and a high-intensity camera, allowing researchers to discover where animals are, how many of them there are and how they're distributing themselves over space and time, she says.
"It is a more accurate way to measure some sea life," says Helga Gomes, an oceanographer at Bigelow Oceanographic Institute in Boothbay Harbor, Maine. "It's not invasive in the way that nets are. You can lose a lot of animals in nets, but with non-invasive technology you can observe ocean life where it is, without disturbing it."
Ultimately, leaving the sea undisturbed is Widder's real concern. She says that less than 5 percent of our oceans have been explored. "If we want to be good stewards of the ocean, we have to understand the life in the ocean," she believes.
But the U.S. Navy wants to understand bioluminescence for a different reason. Because movement can trigger bioluminescence on the sea's surface, subs leave a glowing trail when on patrol. In both World Wars each side sank submarines after spying a glowing path across the ocean surface. Now, the Navy aims to map where the largest density of bioluminescence is in oceans so subs can navigate around those areas, prowling the seas undetected.
Then there are the biologists that are learning from bioluminescence. In the late 90s, the muck that was cellular activity was illuminated by green fluorescent chemicals extracted from sea animals. Biologists use animals' chemicals to light up cells from the inside. "It has had a tremendous impact on all ranges of biology, molecular biology, genetic engineering," Widder says, adding that future uses for such chemicals include harnessing their properties to study arthritis.
For Widder, the journey to shed light on what the sea does down below has just begun. The sea's mysteries may well unlock keys to counting ocean populations with better accuracy, seeing the human cell in more intricate detail than ever before, and policing hundreds of miles of U.S. coastline undetected.
Widder received funding to develop the camera from Harbor Branch Oceanographic Institution, Monterey Bay Aquarium Research Institute, NOAA, and the Office of Naval Research.
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