Scientists discover 100-million-year-old bacteria under South Pacific seafloor.
- SIGMABIOL
- Jul 29, 2020
- 2 min read
Key points:
The microbes were present in clay samples about 74.5 meters under the seafloor, below 5.7 km of water
Geomicrobiologist Yuki Morono incubated the microbes for up to 557 days in a secure laboratory setting
The microbes were aerobic — requiring oxygen to live — and oxygen was present in the sediment samples
Scientists have revived bacteria that survived more than 100 million years laying dormant on the seafloor. The microbes, spanning 10 major and numerous minor groups of bacteria, maybe the planet's oldest-known organisms.
Yuki Morono, a geomicrobiologist with the Japan Agency for Marine-Earth Science and Technology, led a team of researchers who retrieved the microbes from sediment underneath the waters of the South Pacific.
The scientists said the microbes were present in clay samples drilled from the research vessel JOIDES Resolution about 74.5 meters under the seafloor, below 5.7 kilometers of water.
Up to 99 percent of the microbes, dating back to the age of dinosaurs, were found encased in the sediment and survived despite having essentially no nutrients for all that time.
Dr. Morono incubated the microbes for up to 557 days in a secure laboratory setting, providing carbon and nitrogen food sources such as ammonia, acetate, and amino acids.
The microbes grew, multiplied, and displayed diverse metabolic activities.
"It is surprising and biologically challenging that a large fraction of microbes could be revived from a very long time of burial or entrapment in extremely low nutrient/energy conditions," Dr. Morono said.
The microbes were aerobic — requiring oxygen to live — and oxygen was present in the sediment samples. This indicates that if sediment accumulates gradually on the seafloor at a rate of no more than a meter or two every million years, oxygen may remain present to enable such microbes to survive stupendous lengths of time.
Research published in 2000 described reviving bacteria inside 250-million-year-old salt crystals from Texas, but there is a dispute regarding the age of those microbes.
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