An international team of researchers has succeeded in reviving microbes that have been stuck in hibernation in a seemingly life-free seabed area for more than 100 million years.
In their study, published in the journal Nature Communications on July 28, the team of Japanese and American scientists aimed at finding out whether microscopic life could remain in conditions less than hospitable beneath the bottom of the Pacific Ocean.
Even in the most extreme conditions
"We wanted to know how long microbes can save their lives in an almost foodless state," said microbiologist Yuki Morono of the Japan Marine Science and Technology Agency (JAMSTEC), who led the study as reported by the Science Alert website. ".
Scientists have obtained the following response: Microbes trapped in seabed sediments deposited 100 million years ago can be resuscitated by providing the right food and a little extra oxygen.
The matter was impressive. The pressure on the microbes on the sea floor is immense from all of that water piled up on the sea floor, in addition to the lack of oxygen, the presence of a few essential nutrients, and the negligible energy supply.
When life is confined to other high-pressure environments, fossils usually form after a million years or more, but these powerful microbes were very alive.
"We knew that there was a life in deep sediments near continents where there is a lot of organic matter buried ... but what we found is that life extends deep in the ocean from the bottom of the sea down to The bottom rocky base. "
The most limited food
The soil where the microbes were trapped was taken from an expedition in 2010 to the South Pacific Gyre, a seemingly lifeless region in circular ocean currents to the east of Australia, known to be one of the most limited food areas and deficient in Life in the ocean, as well as the rubbish vortex, with all the plastic pollution that the ocean collects on its surface.
As part of a 2010 trip on the JOIDES Resolution drilling rig, the team excavated the nuclei of sediments up to 75 meters below the sea floor, about 6 kilometers below the ocean's surface.
They took samples from the clay of ancient marine sediments, which accumulates in the deepest and most remote parts of the ocean, and the smallest chalky fossil filtrate, ranging between 4.3 million years and 13 million years old.
In these samples, they found microbes consuming oxygen (and dissolved oxygen) directly in each layer of nuclei, from top to bottom, and in every location where they took samples in the South Pacific, but the microbes were hidden in very low numbers.
Even in the oldest sediments
On board the ship, samples of sediment nuclei were taken to see if the energy-thirsty microbes retained their "metabolic capacity" and whether they could feed and multiply or not.
Older microbes were given a boost of oxygen and a feeding of traceable substrates containing carbon and nitrogen, which is their favorite food, and before glass bottles were closed, placed in incubators and opened only after 21 days, 6 weeks, or 18 months.
The result was that, even in the oldest sediments from which samples were taken, researchers were able to revive up to 99% of the original microbial community.
"At first I was skeptical, but we found that 99.1% of the microbes in the sediments dating back to 101.5 million years were still alive and ready to eat," Morono said.
After a long incubation, the microbial communities were sorted based on their genes, and the researchers mentioned that bacteria dominate the seafloor soils, but not the type that spores, which means they were ready to grow as soon as they were given the right food. The microbes have quadrupled and consumed available carbon and nitrogen within 68 days in their incubation.
Hardness of life will
"It seems that there are no limits to life in ancient sediments around the world ... In the oldest sediments that we dug, with the least amount of food, there are still living beings, and they can wake up, grow, and multiply," Dehont says.
The depths of the oceans did not show the extent of their hardness and the strength of the will of life deposited in them only, as scientists also found this in microbes that live in harsh conditions in Antarctica, and others live in the drier deserts.