Japanese scientists say they have revived microbes that have been dormant for more than 100 million years.
These tiny organisms survive on the ocean floor of the South Pacific – in nutrient-poor deposits, but have enough oxygen to allow them to live.
Microbes are among the simplest organisms in the world, and some can live in extreme environments, where more advanced life forms cannot survive.
After being incubated by scientists, the microbes began to eat and reproduce.
The research was led by the Japanese Agency for Marine-Earth Science and Technology and is published in the journal Nature Communications.
“When I found them, I first doubted whether the findings came from an error or failure in the experiment,” lead author Yuki Morono told AFP.
Professor and author of the report Steven D’Hondt, from the University of Rhode Island, said the microbes came from the oldest samples taken from the ocean floor.
“We now know that there is no age limit for (organisms in) the underwater biosphere”.
Previous studies have shown how bacteria can survive in extreme places, including around underwater vents that are devoid of oxygen.