OSLO Many octopuses evolved from a common ancestor that lived off Antarctica more than 30 million years ago, according to a "Census of Marine Life" that is seeking to map the oceans from microbes to whales.
Researchers in 82 nations, whose 10-year study aims to help protect life in the seas, found a mysterious meeting place for white sharks in the eastern Pacific Ocean and algae thriving at -25 degrees Celsius (-13 Fahrenheit) in the Arctic.
"We are approaching a picture of the oceans ... from micrcobes to whales," said Ron O'Dor, co-senior scientist of the census of the 2007-08 findings by up to 2,000 scientists.
The $650 million census is on track for completion in 2010, assessing about 230,000 known marine species, a statement said. It has identified 5,300 likely new species, of everything from fish or corals. So far, 110 have been confirmed as new.
Among the findings, genetic evidence showed that the tentacles of the octopus family pointed to an Antarctic ancestor for many deep sea species. A modern octopus called adelieledone in Antarctica seemed the closest relative of the original.
Octopuses apparently spread around the world after Antarctica became covered with a continent-wide ice sheet more than 30 million years ago, a shift that helped create oxygen-rich ocean currents flowing north, a report said.
"Isolated in new habitat conditions, many different species evolved; some octopuses, for example, losing their defensive ink sacs -- pointless at perpetually dark depths," the census said.
Other findings showed that white sharks traveled thousands of kilometers to spend six months at what researchers called the "White Shark Cafe" in the Pacific between Hawaii and California.
"During this time, both males and females make frequent, repetitive dives to depths of 300 meters" it said. Researchers said the purpose was unknown but may be linked to food or reproduction.
Mapping the oceans is helping researchers to work out how to protect marine life from threats including over-fishing, pollution and climate change. The census could identify areas needing conservation, or help define rules for seabed mining.
At one extreme, scientists found algae thriving in Arctic waters of -25 Celsius, kept from freezing because salt concentrations were six times more than in normal sea water.
And in the mid-Atlantic, researchers found anemones, worms and shrimp around the world's deepest known active hot volcanic vent, over 4,100 meters deep.
Among other findings were a predatory comb jelly anchored to the seabed in waters 7,217 meters (23,680 ft) deep near Japan. "It was found at a depth thought incapable of supporting predators like this one," a statement said.
The discovery of a wealth of new species was not a sign that the oceans were healthier than thought.
"The things that we're discovering ... are not the kind of things you want to see on your plate very often," O'Dor said, adding that people had fished the big, attractive species.
Even so, 95 percent of the ocean was unexplored. The census "will synthesize what humankind knows about the oceans, what we don't know, and what we many never know," Ian Poiner, chair of the census's steering committee, said in a statement.
(Editing by Elizabeth Piper)