Scientists have brought back to life microbes found in 100 million sediments from deep below the ocean floor. The experiment sheds new light on where life on Earth can be found – and how resilient it is.
According to a new study published in the journal Nature Communications, microbes found buried under the seabed exist for up to 1
It is a mystery how microbes managed to survive in the harsh conditions of their environment – and it is not clear how long they can live. Researchers say they may be the oldest known organisms on the planet.
Scientists from the Japan Agency for Marine and Terrestrial Sciences and Technology analyzed samples of sediment found approximately 12,140 by 18,700 feet below the ocean surface in the South Pacific, a system of rotating currents located in the Pacific Ocean. The center of the South Pacific contains the “ocean pole of inaccessibility” – the place of the Earth furthest from the whole earth – the part with the lowest productivity of the whole ocean.
The area has little food, but there is a lot of oxygen deep under the attic floor. Sedimentary layers collected during an expedition in 2010 were deposited over a period of 13 million to 101.5 million years.
Within the sediment, scientists found marine microbes: tiny single-celled microorganisms that make up most of the total mass of living things in the ocean. Caught in the sediment layers, they could barely move or feed.
The researchers wanted to know if life could exist in such a nutrient-poor environment.
In the lab, the researchers were able to wake the germs from their long nap. They gave the ancient samples carbon and nitrogen substrates to test if they were cables to feed and divide more cells.
Over a period of 68 days, the vast majority of nearly 7,000 cells respond quickly to new conditions, multiplying by four orders of magnitude – even in the oldest samples. According to the researchers, aerobic bacteria dominated the experiment.
“What we’ve found is that life extends from the seabed to the base of rocky basements,” said University of Rhode Island oceanographer and study co-author Stephen D’Hond in a video news release. “These organisms are not only alive in the deepest, oldest sediment, but are able to grow and divide.”
“Surprisingly and biologically challenging, much of the microbes can be revived from a very long time of burial or confinement in extremely low nutritional / energy conditions,” lead author Yuki Morono told Reuters.
The study suggests that microbes could survive for previously unattainable intervals if the sediment accumulates at a very slow rate, trapping oxygen over time.
Through further experiments, researchers now hope to determine how microbes have been able to survive for millions of years.
“The most exciting part of this study is that it basically shows that there is no limit to life in the old sediment of the earth’s ocean,” D’Hond told Reuters. “Maintaining full physiological capacity for 100 million years in starvation isolation is an impressive feat.”