News / Industry News & Events / Deep secret: Bioluminescence is common trait under the sea (08/24/17)

Deep secret: Bioluminescence is common trait under the sea

08/24/17

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Scientists find that 76% of creatures in the ocean use light to lure, intimidate, stun, mislead, find mates and thrive

Biologists know that the creatures of the deep sea use light much as animals on land use sound to lure, intimidate, stun, mislead and find mates.

The living lights emanated from tiny fish with needle-like fangs, and gelatinous brutes with thousands of feeding tentacles. The sheer variety suggested that bioluminescence was fairly common, but no scientist came up with a measurement of the phenomenon.

Now, scientists have succeeded in gauging the actual extent of bioluminescence in the deep ocean.

During 240 research dives in the Pacific, they recorded every occurrence and kind of glowing sea creature more than 500 types living down as deep as 3 km. The team merged the results into a comprehensive survey. The result? Most of the creatures a stunning 76% made their own light, vastly outnumbering the ranks of the unlit, such as dolphins.

People think bioluminescence is some kind of exotic characteristic, said Sverine Martini, a marine biologist and lead author of the study, published in Scientific Reports . Even oceanographers dont realize that its common.

As the deep sea is the planets largest habitat, the new findings confirm bioluminescence to be one of the earths dominant ecological traits, despite its unfamiliarity, according to Ms. Martini and her co-author, Steven H.D. Haddock, both of the Monterey Bay Aquarium Research Institute in California.

240 dives

The 240 dives used to perform the survey were all research trips Mr. Haddock had conducted personally since arriving in 1999 at the institute.

The sea floor off Monterey Bay, about 100 km south of San Francisco, drops off sharply, unlike the shallow continental shelves on most coasts. That makes it easy for research vessels to quickly reach and access deep environments.

For years, Mr. Haddock and his colleagues lowered robots on long tethers to explore the icy darkness. Sensitive cameras on the vehicles let the scientists conduct wide visual hunts. In all, the researchers made more than 3,50,000 sightings of deep-sea life. Their finds included angler fish, a famous example of bioluminescence. These skilled hunters lure prey by dangling lines tipped with glowing lures in front of large mouths full of dagger-like teeth.

Vampire squid

A rare sighting was Vampyroteuthis infernalis Latin for vampire squid from hell. The odd creature has blue eyes, a dark red body and cloak-like webbing over its arms. The tips glow.

Mr. Haddock and his colleagues have discovered that the squids also emit luminous blue particles that can form a glowing cloud around the animal, apparently to distract predators so the squid can vanish into darkness.

Most siphonophores gelatinous creatures light up brightly. Scientists judge their startling brilliance to be a way to scare off predators. Mr. Haddock and his colleagues uncovered another reason while studying a creature known as Erenna. The ends of its tentacles turned out to bear twitching red lights, apparently for drawing prey into waiting stingers and its stomach.

The full extent of bioluminescence capability is yet to be established, especially in the deep sea where continued discoveries await, Ms. Martini and Mr. Haddock said in their report.NYT