Deepest secrets of the Marianas Trench revealed

LONDON - Scientists have unveiled the climate secrets of the deepest part of the ocean-the Marianas Trench in the western Pacific Ocean.

An international team of scientists used a submersible, designed to withstand immense pressures, to study the bottom of the 10.9km deep underwater canyon.

The early results have revealed that ocean trenches are acting as carbon sinks and they may play a larger role in regulating the Earth’s chemistry and climate than previously thought.

Although two explorers, Jacques Piccard and Don Walsh, reached the deepest part of the Marianas Trench-a point called the Challenger Deep-in 1960, no humans have been back since.

Lead researcher Ronnie Glud, from the University of Southern Denmark and the Scottish Association for Marine Science (Sams), said that working at more than 1,000 atmospheres of pressure was challenging, but advances in technology had made it possible.

“This is the first time we have been able to set down sophisticated instruments at these depths to measure how much carbon is buried there,” the BBC quoted him as saying.

Glud, working with scientists from the Japan Agency for Marine Earth Science and Technology (Jamstec) and from the UK and Germany, used a lander equipped with special sensors packed in a titanium cylinder that was able to resist the remarkable pressures.

The lander was launched from a ship and took three hours to free-fall to the sea bottom, where it carried out pre-programmed experiments before releasing its ballast and returning to the surface.

The tests helped the scientists to assess the abundance of carbon at those murky depths.

“Our results very strongly suggest that the trenches do act as sediment traps. And they also had high activity, meaning that more carbon is turned over by bacteria in the trenches than is turned over at 6,000m of depth in the abyssal plain.

“What it means is that we have carbon storage going on in these trenches that is higher than we thought before, and this really means that we have a carbon dioxide sink in the deep ocean that wasn’t recognised before,” said Glud.

The next stage for the team is to quantify their results and work out exactly how much more carbon is stored in deep-sea trenches compared with other parts of the sea, and how much carbon turnover by bacteria is being carried out.

This should help them to better establish the role of the ocean trenches in regulating climate, said the researchers. (ANI)