OSLO - Microbes have been found living at a record depth of 1.6 km (a mile) beneath the Atlantic seabed in a hint that life might also evolve underground on other planets, scientists said on Thursday.
The discovery of prokaryotic microbes in searing hot sediments under the seabed off Newfoundland, Canada, doubles the previous depth record of 842 metres, according to experts in Wales and France writing in the journal Science.
"This is the deepest, oldest and hottest marine sediments that prokaryotic life has been found in," John Parks, a professor at the University of Wales who was a co-author, told Reuters.
The microbes were found at 1,626 metres below the seafloor in sediments 111 million years old and at temperatures of 60 to 100 degrees Celsius (140-212.00 Fahrenheit), the report said.
Prokaryotes are microbes lacking nuclei, comprising archaea and some types of bacteria. The lack of cell nuclei distinguishes them from eukayrotes, or all animal and plant life.
"If there is a substantial subsurface biosphere on earth there could also be substantial biospheres on other planets," Parks said, estimating that such microbes could survive temperatures down to about 4 km below the seabed on earth.
"Just taking a scoop from the surface of Mars is not going to tell you whether there is life on Mars or not," he said.
It was unclear if the microbes off Newfoundland had any connection to the sun's energy which is the source of life at the surface – they might eat buried methane, for instance, formed by compressed plants millions of years ago.
