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.
10-year study
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 microbes 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, 3000 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 whit sharks traveled thousands of kilometers to spend six months at what researchers called the “White Shark Café” in the Pacific between Hawaii and California.
Repetitive dives
“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.
