The deep has a lot more light than you might think.
A recent study by Séverine Martini and Steve Haddock, researchers at the Monterey Bay Aquarium Research Institute in Moss Landing, found that three-quarters of marine animals in Monterey Bay—from the surface to 4,000 feet deep—are capable of producing their own light.
According to a statement from MBARI, the study, which was published April 4 in the journal Scientific Reports, "represents the first detailed, quantitative analysis of deep-sea bioluminescence."
Martini and Haddock counted over 350,000 individual animals from videos taken by MBARI's remote operate submersibles, and compiled data for every animal that appeared larger than a centimeter.
One surprising discovery the study revealed was that the proportion of bioluminescent animals was similar at all depths. However, the type of animals that were bioluminescent—jellies, worms, or tadpole-like animals called larvaceans—changed depending on the depth.
"I'm not sure people realize how common bioluminescence is," Martini says in the statement. "It's not just a few deep-sea fishes, like the angler fish. It's jellies, worms, squids...all sort of things.
"Given that the deep ocean is the largest habitat on Earth by volume," she continues, "bioluminescence can certainly be said to be a major ecological trait on Earth."