Scientists have successfully revived small microbes trapped in their sleep in a seemingly hopeless zone of the seabed for more than 100 million years.
A team of scientists from Japan and America was looking to see if microscopic life would survive in less hospitable conditions under the Pacific Seabed.
“We wanted to know how long microbes can keep their lives almost in the absence of food,” said microbiologist Yuki Morono of the Japan Marine Science and Technology Agency, who led the study.
They got their answer: microbes that were trapped in seabed sediments deposited 100 million years ago could be revived with the right food and a little added oxygen.
What is impressive. The pressure is huge for microbes on the seabed, all the amount of water accumulated on the seabed. Not to mention a lack of oxygen, a few basic nutrients and pointless energy supplies.
When life is trapped in other high-pressure environments, fossil forms usually form over millions of years or more, but these powerful microbes have been very alive.
“We knew that in deep sediments there was life near continents where there were a lot of buried organic matter,”; said Moron’s colleague, geomicrobiologist Steven D’Hondt of the University of Rhode Island. “However, we have found that life stretches in the deep ocean from the seabed to the underlying rocky basement.”
The soil in which the microbes were captured was obtained from a 2010 expedition to the South Pacific Ocean of Gyre, a seemingly hopeless zone in the middle of eddy currents east of Australia, known as one of the most restricted foods and vital parts. ocean (and rubbish vortex, with all the plastic pollution it collects on the surface).
As part of an expedition in 2010 aboard the JOIDES Resolution drill, the team extracted sediment cores reaching up to 75 meters (250 feet) below the seabed, which lies nearly 6 kilometers (almost 20,000 feet) below ocean level.
They took samples from ancient pelagic clay, which accumulates in the deepest and most remote parts of the ocean, and much younger and chalk nanofossil sludge, 4.3 to 13 million years old.
They found oxygen-consuming microorganisms (and dissolved oxygen) directly through each layer of nuclei, from top to bottom to all of the sampling sites in the South Pacific. However, microbes were hidden in very small numbers.
Sediment cores were sampled on board the ship to see if energy-hungry microbes had retained their “metabolic potential” and could feast and multiply.
Ancient microbes were given oxygen and fed traceable substrates containing carbon and nitrogen, their food of choice, before closing the glass vials, incubating and opening up to 21 days, 6 weeks or 18 months.
Even in the oldest sediment samples, researchers were able to revive up to 99 percent of the original microbial community.
“At first I was skeptical, but we found that up to 99.1 percent of the microbes in the sediment deposited 101.5 million years ago were still alive and ready to eat,” Morono said.
After a long incubation, the microbial communities were arranged according to their genes. The researchers said that the soils of the seabed are dominated by bacteria, but not the type that forms spores, which means that they were ready to grow as soon as they received the right food.
Some microbes increased fourfold and consumed 68 days of available carbon and nitrogen for incubation.
“It shows that life in the old sediment of the world’s oceans is not limited,” D’Hondt said. “In the oldest sediment we drilled, with the least amount of food, there are still living organisms and they can wake up, grow and multiply.”
Microbes have shown how resilient they can be not only in the depths of the oceans. Researchers have also found microorganisms living in extreme conditions in Antarctica, as well as the driest deserts.
The study is published in Natural communications.