Scientists recently discovered catsharks exhibiting an incredibly cool phenomenon deep in the ocean. We see the sharks as drab brown, but a new study suggests they see each other as glowing green. The phenomenon is called biofluorescence, and the glowing sharks are detailed in new study led by David Gruber from the City University of New York.
Gruber said, “Imagine being at a disco party with only blue lighting, so everything looks blue. Suddenly, someone jumps onto the dance floor with an outfit covered in patterned fluorescent paint that converts blue light into green. They would stand out like a sore thumb. That’s what these sharks are doing.”
Gruber’s team looked at shark eyes and noticed they only have one color pigment in their eyes, so they likely only see hues of blue and green. Biofluorescence may help the sharks stand out in a blue-green world to other sharks nearby.
This phenomenon is different from bioluminescence, which involves a chemical reaction. Instead biofluorescence occurs when sharks re-emit light at a different wavelength than the one they took in. Using underwater cameras with yellow filters, the scientists were able to capture the sharks glowing.
Since the creatures tend to glow all over, from their skin to even their eyes, Gruber thinks it could be important to how they function and possibly communicate.
Gruber is at the forefront of the study of biofluorescent creatures – so far he has detailed 180 of them in one paper. “I just find this real serenity and beauty to being in the reef at night,” Gruber said. “When we add on this fluorescent layer it’s like being on another planet.”
Images via screenshot