Ocean depths home to exotic life

A total of 17,650 species of animals, also including shrimps, corals, starfish or crabs, have been identified in the frigid, sunless waters down to about 5 km (3 miles) deep.

“The diversity of life in the deep sea is much, much greater than we’ve believed,” said Robert Carney of Louisiana State University, who co-leads a study of the ocean depths. “The abyss is not the dark hole any more,” he told ‘Reuters’ of surveys with deep-towed cameras, sonars and other technology.

Light typically penetrates about 200 metres into the seas—comparable to the height of the 169-metre Washington Monument obelisk— and the zone beyond has long been viewed as a desert with crushing pressures.

Beyond the sunlit area where plants can grow, creatures have to exploit bacteria, for instance that break down methane or oil, or food falling from the surface such as whale carcasses.

Among creatures were luminous jellyfish and gelatinous creatures known as finned octopods, or “Dumbos” because they flap ear-like fins and look like the cartoon flying elephant.

“Siphonophores have been reported to be longer than a blue whale,” he told ‘Reuters’. The Census of Marine Life is a 10-year project due for completion in October 2010.

Oil drilling

In one part of the Gulf of Mexico, experts found a tubeworm at 990 metres deep on the seafloor. When a robotic arm lifted it from a hole on the seabed, oil gushed out- it was consuming chemicals from decomposing oil. Carney said that oil companies focused most on geological surveys to find deposits but that the presence of tubeworms could also be a marker. Still, Carney said many scientists were “bothered by the prevalence of the view that the deep sea is of no concern” and that a drive to exploit resources was getting ahead of knowledge of the depths and the creatures that live there.

Little is known about them. Only seven of 680 specimens of tiny crustaceans known as copepods recently collected in the southeastern Atlantic could be identified.
Although the ocean depths are permanently black, many animals create their own light— with luminous markings to help spot or attract prey or a mate—and have working eyes.