Single-cell organisms found in ocean depth

Japanese scientists have discovered single-cell organisms living in the Pacific Ocean's deepest trench, the Challenger Deep, according to an article published on Friday in Science magazine.

The microscopic organisms were found in sediment at a depth of 10,896 metres, with the help of a KAIKO Remote Operated Vehicle belonging to the Japan Agency for Marine Earth Science and Technology (JAMSTEC), said scientists from Shizuaka University.

'Almost nothing is known about small sediment-dwelling organisms living in these environments, which are among the most remote on Earth,' explained researchers Yuko Todo, Hiroshi Kitazato, Jun Hashimoto and Andrew Gooday in their study.

Foraminifera are simple plankton, commonly found at the ocean's surface. While the organisms found in the Challenger Deep are similar to the regular hard-shelled foraminifera, they have soft cell walls, the scientists said.

The pressure on the ocean bed is about 1,100 atmospheres as measured at the ocean's surface, near the Mariana Islands and the US territory of Guam.

'The Challenger Deep may have developed to its present depth during the past six million to nine million years,' the article said.

'Its very distinctive foraminiferal fauna probably represent the remnants of an abyssal assemblage that was able to adapt to the steady increase in hydrostatic pressure over this time period,' the study said.