Nobody expected single-celled creatures to exist for so long.
Microbes were discovered buried in the earth 101.5 million years ago, long before Tyrannosaurus rex and the planet’s largest meat-eating dinosaur, Spinosaurus, inhabited the Earth. Time passed, continents altered, oceans rose and sank, big apes appeared, and ultimately human beings developed the curiosity and abilities to unearth those ancient cells. Researchers have now brought the single-celled creatures back to life in a Japanese lab.
Ten years ago, researchers aboard the drillship JOIDES Resolution gathered soil samples from the ocean’s depths. The samples were taken 328 feet (100 meters) below the South Pacific Gyre’s 20,000-foot-deep (6,000-meter) floor. The researchers were hoping for information on how bacteria cope in such a distant portion of the Pacific Ocean, where there are few nutrients and little oxygen available for life to exist.
In a release, Yuki Morono, a scientist at the Japan Agency for Marine-Earth Science and Technology and lead author of a new research on the bacteria, stated, “Our major issue was whether life could persist in such a nutrient-limited environment or if this was a dead zone.” “We also wanted to see how long the microorganisms could survive in the absence of nourishment.”
Their findings suggest that when oxygen and nutrition become accessible, even cells identified in 101.5 million-year-old sediment samples may wake up.
“At first, I was doubtful,” Morono explained, “but we discovered that up to 99.1% of the microorganisms in sand deposited 101.5 million years ago were still alive and ready to eat.”
The bacteria had ceased to be active in any way. They were active again when given nourishment and other needs of life.
To ensure that their sample was free of contemporary microorganisms, the researchers split up the sand in a sterile environment, choosing the microbial cells present and feeding them nutrition solely through a small tube intended to prevent contamination from entering.
The cells reacted, and many of them did so fast. They ate up nitrogen and carbon fast. The overall cell count has doubled in 68 days from the initial 6,986.
Aerobic bacteria, which breathe oxygen, were the toughest and most likely to wake up. These microscopic creatures were living only on the small air bubbles that settle into dirt across geologic eons. Aerobic bacteria’s metabolic rate appears to be just sluggish enough to allow them to exist for such long periods of time.
The findings were published in the journal Nature Communications on July 28.
