1 of 4. A Southern Ocean elephant seal wears a sensor on its head as it sleeps on an island in the Southern Ocean, Antarctica in this handout photo taken February 27, 2012. Elephant seals wearing head sensors and swimming deep beneath Antarctic ice have helped scientists better understand how the ocean's coldest, deepest waters are formed, providing vital clues to understanding its role in the world's climate. The tagged seals, along with sophisticated satellite data and moorings in ocean canyons, all played a role in providing data from the extreme Antarctic environment, where observations are very rare and ships could not go, said researchers at the Antarctic Climate & Ecosystem CRC in Tasmania. The sensor weighs about 100 to 200 grams and has a small satellite relay which transmits data on a daily basis. Picture taken February 27, 2012. Credit: Reuters/Mark Hindell/Antarctic Climate and Ecosystems CRC/Handout

(Reuters) – Elephant seals wearing head sensors and swimming deep beneath Antarctic ice have helped scientists better understand how the ocean's coldest, deepest waters are formed, providing vital clues to understanding its role in the world's climate.

The tagged seals, along with sophisticated satellite data and moorings in ocean canyons, all played a role in providing data from the extreme Antarctic environment, where observations are very rare and ships could not go, said researchers at the Antarctic Climate & Ecosystem CRC in Tasmania.

Scientists have long known of the existence of "Antarctic bottom water," a dense, deep layer of water near the ocean floor that has a significant impact on the movement of the world's oceans.

Three areas where this water is formed were known of, and the existence of a fourth suspected for decades, but the area was far too inaccessible, until now, thanks to the seals.

"The seals went to an area of the coastline that no ship was ever going to get to," said Guy Williams, ACE CRC Sea Ice specialist and co-author of the study.

"This is a particular form of Antarctic water called Antarctic bottom water production, one of the engines that drives ocean circulation," he told Reuters. "What we've done is found another piston in that engine."

Southern Ocean Elephant seals are the largest of all seals, with males growing up to six meters (20 feet) long and weighing up to 4,000 kilograms (8,800 lbs).

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