Sharks glow green in the depths of the ocean
Credit: David Gruber, City University of New York Glowing bright green may not seem like the most effective disguise, but some sharks take on the colour to make sure only their own kind can identify them. And while a green hue may be a sign of illness in humans, it could help the sharks fight off infections, scientists say. In the depths of the sea, certain species transform the ocean's blue light into a bright green colour that only other sharks can see. Researchers have now identified what lies behind this transformation - a family of small-molecule metabolites. They say this method of biofluorescence is different from how most marine creatures glow.