Japan: Scientists successfully awakened microorganisms in ancient sediments, promoting them to grow and multiply in the laboratory.
Microorganisms in sediment 101.5 million years. Photo: Phys.org.
In the new study published on July 28 in the journal Nature Communications, a group of researchers from Japan discovered that if given the food at the right laboratory conditions, 100 million-year-old microorganisms collected from sediments can be revived and multiplied, even when inactivated since the time when the great dinosaurs roamed the Earth.
The team comes from the Japan Oceanography and Earth Science and Technology Agency (JAMSTEC), URI School of Oceanography, Institute of Advanced Industrial Science and Technology, Kochi University and Marine Works Japan, Sampling ancient sediments decades ago during the South Pacific Gyre alternating ocean current expedition, where there was the least amount of nutrients to feed a marine food web.
“Our main concern is whether life can survive in a nutrient-restricted environment or this is a non-life zone,” said lead researcher Yuki Morono, scientist at JAMSTEC. “And we want to know how long microorganisms can sustain life in the absence of food.”
At the sea floor, there are many layers of sediment, including sea snow (organic debris falling from the sea surface), dust and particles brought by wind and currents. Small life forms like microorganisms can be trapped in sediments.
On board the research vessel JOIDES Resolution, Morono and his colleagues drilled multiple cores of sediment at a depth of 100 meters below the sea floor and nearly 6,000 meters above sea level. The team found that oxygen exists at every core, revealing that if sediment accumulates slowly on the seabed at a rate of 1-2 meters after a million years, the oxygen will penetrate through the seabed. This condition allows aerobic microorganisms to persist for millions of years.
After refining the experimental procedure, the team incubated the samples for the growth of microorganisms. The results showed that the microorganisms in the sediment survived a long period of inactivity, continue to grow and multiply. The discovery surprised Morono. “At first I was skeptical, but then we found that 99.1% of the bacteria in the sediment that had been deposited 101.5 million years ago are still alive and ready to eat,” Morono said.
The researchers hope to apply the same approach to answer other questions about the geological past. According to Morono, the life of bacteria on the seabed is very slow compared to bacteria above the water, so their evolution rate is also slower. “We want to find out how these ancient microbes evolved. Research also shows that the area below the sea floor is the perfect place to explore the limits of life on Earth,” Morono said. .