Scientists have recovered life microbes found in sediments 100 million years old from deep below the sea level. This experiment brings new light to where life can be found on Earth – and just how flexible it can be.
According to a new study published in the journal Nature Communications, germs found buried under the sea have survived for 101.5 years. Depressions do not require energy that allows cells to sustain themselves, but scientists were still able to revive communities.
It is a mystery how the germs could survive the harsh conditions around them – and it is unclear how long they can live. Researchers said they are possibly the oldest living organisms on the planet.
Scientists at the Japan Agency for Marine-Earth Science and Technology analyzed sediment samples, which were found from about 12,140 to 18,700 feet below sea surface in the South Pacific gyre, a system of swirling currents located in the Pacific Ocean. The center of the South Pacific Gyre consists of the “oceanic pole of inaccessibility”, which is the farthest from Earth on Earth – the lowest productivity part of the entire ocean.
There is very little food in this area, but it deepens a lot of oxygen beneath the sub-region. The layers of sediment collected during the 2010 campaign were deposited in the period from 13 million to 101.5 million years ago.
Within the sediment, scientists found marine microbes: small, single-celled microorganisms that make up the overwhelming majority of the total mass of living organisms in the ocean. Trapped in sedimentary layers, they could barely walk or eat.
Researchers wanted to know if life could exist in such a nutrient-poor environment.
Back at the lab, the researchers were able to remove germs from their prolonged sleep. They gave carbon and nitrogen substrates to ancient specimens to test that they were cables feeding and dividing into more cells.
Over a period of 68 days, the vast majority of approximately 7,000 cells responded rapidly to new conditions, multiplied by four orders of magnitude – even in the oldest samples. Researchers said that aerobic bacteria were dominant in the experiment.
“What we have found is that life extends from the path of the ocean to the underlying rocky basement,” Rhode Island oceanographer and study co-author Steven D’Hondt said in a video news release. “Those organisms not only survive in the deepest, oldest sediment, but they are capable of growing and dividing.”
“It is surprising and biologically challenging that a large fraction of microbes can be regenerated over a very long time, buried or trapped in very low nutrient / energy conditions,” lead author Yuki Morono told Reuters.
Research indicates that germs can survive for an infinitely long period of time if sediment accumulates at a very slow rate, with oxygen trapped over time.
Through further experiments, researchers are now expected to determine how the germs were able to sustain for millions of years.
D’Hond told Reuters, “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.” “Maintaining full physical capacity for 100 million years in hungry isolation is an impressive achievement.”