Family ties: Megeleledone setebos (bottom left), endemic to the Southern Ocean, surrounded by related octopus species that evolved in the deep-sea.
Credit: Census of Marine Life
SYDNEY: The ancestry of deep-sea octopuses, a white shark "café" and a city of brittle stars are among the discoveries revealed this week by a global marine census.
The latest figures from the Census of Marine Life, a collaboration of 2,000 scientists from 82 nations, adds 5,600 new species – 110 of which have been formally described – towards an estimated quarter of a million known marine species.
The census is a 10-year initiative to track the vast and mostly-unknown diversity of the world's oceans.
DNA barcoding
In addition to videoing, tagging and netting marine life, scientists utilised a DNA 'barcoding' system to speed up identification of marine species, many of which are under threat from climate change, acidification and over-fishing.
Participants will report on the progress of the census daily at the World Conference on Marine Biodiversity in Valencia, Spain, this week.
"We expect to have much-improved tools for predicting the presence or absence of various species based on what we know about a particular environment," said Canadian deep sea biologist Paul Snelgrove, leader of the team integrating findings from all 17 Census projects.
"In fact, the census may offer a new map, a new biogeography, of all ocean life," said Snelgrove of the Ocean Sciences Centre in St Johns, Newfoundland.
Scientists report that satellite tagging of white sharks has revealed a "shark café" where the threatened species congregate each winter in the Pacific and periodically dive to depths of over 300 m.
Researchers will also divulge this week that deep sea octopuses share a common Antarctic ancestor, which then evolved into new species and spread around the globe.
Tasman sea discoveries
Other recent highlights of the census were high diversity of life on seamounts off the continental shelf of Australia, south of Tasmania, where tens of millions of brittle stars and coral-like organisms were found living arm tip to arm tip in the swirling circumpolar current.
Ecologist Graham Hosie, from the Australian Antarctic Division, who led the Tasmanian seamount expedition, said the census was "ambitious" but had been "highly successful so far at setting a benchmark in biodiversity for all marine environments".
"If Spielberg wanted to get any ideas for a new movie he should look at some of the critters down there," Hosie said of the organisms he found.
Researchers also found unusual ecosystems that feed-off methane seeping from the seafloor around New Zealand, as well as four-metre high chimneys of methane-based bacterial mats on the floor of the Black Sea.
Studies of the bacteria could contribute to controlling methane emissions to curb climate change, according to the census report. The final census report is due in 2010 when the international project is finished.
