Scientists have brought back to life the microbes found in the 100 millionth sediment from deep under the ocean floor. The experiment sheds new light on where life can be found on Earth – and how sustainable it can be.
According to a new study published in the journal Nature Communications, microbes found buried under the seabed persist for up to 101.5 million years. Sediments do not have the energy needed for cells to support themselves, but scientists have been able to revitalize communities.
The secret is how microbes could survive in the harsh conditions of their environment – and it is unclear how long they can live. Researchers have said that they may be the oldest known organisms on the planet.
Scientists at the Japan Agency for Marine and Terrestrial Science and Technology analyzed sediment samples found from about 12,140 to 18,700 feet below the ocean surface in the South Pacific Mountains, a system of rotating currents located in the Pacific Ocean. In the center of the South Pacific Gire is the “ocean of inaccessibility” – the area on Earth, the furthest from all lands – the part with the lowest productivity of the entire ocean.
There is little food in the area, but it contains a lot of oxygen deep underwater. Layers of sediment collected during the 2010 expedition were deposited between 13 and 101.5 million years ago.
Within the sediment, scientists have discovered marine microbes: tiny single-celled microorganisms that make up the vast majority of the total mass of living things in the ocean. Captured by layers of sediment, they could barely move or eat.
The researchers wanted to know if life could exist in such a poor environment.
Returning to the laboratory, the researchers were able to remove germs from their prolonged drowsiness. They gave the old samples carbon and nitrogen substrates to test if they were a power cord and divided into more cells.
Within 68 days, the vast majority of the nearly 7,000 cells responded quickly to the new conditions, multiplying by four orders of magnitude, even in the oldest samples. The researchers said that the experiment was dominated by aerobic bacteria.
“We’ve found that life runs far from the seabed to the lower rocky basement,” University of Rhode Island oceanographer and study co-author Stephen D’Hondt said in a news release. “These organisms not only live in the deepest, most ancient sediment, but they are able to grow and divide.”
“Surprisingly and biologically difficult, a large proportion of microbes could be revived in a very long time of burial or capture in extremely low nutrient / energy conditions,” lead author Yuki Morono told Reuters.
Research shows that microbes could survive for previously incomparable long periods of time if sediment accumulates at a very slow rate, capturing oxygen over time.
Through further experiments, researchers now hope to determine how microbes could survive for millions of years.
“The most exciting part of this study is that it basically shows that life in the old sediment of the Earth’s ocean has no boundaries,” D’Hondt told Reuters. “Maintaining full physiological capacity for 100 million years in starvation isolation is an impressive feat.”
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