It’s sometimes said that we know more about space than our oceans, but a new study has shed light on one of their more novel features: bioluminescence.
Three in four deep sea creatures can create their own light, according to a new survey which suggests the fabled angler fish isn’t so rare after all.
The mechanism lets ocean animals navigate otherwise pitch-black waters, but the creatures don’t glow continuously, for fear of predators.
This and the fact that only a dim glow is sufficient in the depths of the ocean makes it difficult to capture photos of such creatures.
Previously, scientists have totted up the animals on trips to deep waters in submersibles, but in the latest study, researchers reviewed a lot more data.
A remotely operated vehicle carried out more 240 dives in Monterey Bay, capturing footage from sea level to 4000m deep.
The team at Monterey Bay Aquarium Research Institute (MBARI) counted a total of more than 350,000 creatures which spanned at least a centimetre.
The results were then cross-referenced with lists of animals and animal groups known to be bioluminescent thanks to first hand observations from researchers at MBARI and elsewhere.
From sea level to 1,500 metres, most glowing animals were jellyfish or comb jellies. From 1,500 metres to 2,250 metres, glowing worms were the most common creatures. In the deepest waters, tadpole-like larvaceans made up the majority of glowing animals.
Séverine Martini, co-author of the study at MBARI, said she thought the public might not know how common bioluminescence is: “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, bioluminescence can certainly be said to be a major ecological trait on Earth.”