Deep within the cold abyss, beneath the primordial muck of the seafloor and the sediment of millions of years, ancient microbes sit between life and death…and have now been awakened! Scientists haven’t quite unleashed Neptune’s revenge, but they have revived ancient microbes — possibly over 100 million years old — extracted from the bottom of the South Pacific.
Survivors of that unforgiving place, the ancient microbes may not only help us understand the history and capabilities of life on Earth but open the possibility of finding life where we had previously thought it impossible. “I think it provides some crucial information for understanding the habitability of life on Earth, of course, but also the other planets, such as Mars’ subsurface,” geomicrobiologist Fumio Inagaki told Wired.
The researchers from the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) drilled through 250 feet of sediment, 19,000 feet below the surface, to pull up samples that were 101.5 million years old. Inside those samples were microbial life, spanning major and minor bacterial groups. They were tricky to find; the researchers had to develop specialized search techniques, including chemical tracers meant to smoke out seawater contamination (sample contamination from the present day is the bane of pre-dinosaur bacteria hunters.)
The microbes were aerobic, meaning they require oxygen to live, and there was indeed oxygen in the samples, albeit not much. Encased in an environment with little food, the microbes had simply lain dormant for eons. By providing the samples oxygen and nutrients, the bacteria began to multiply, increasing by four orders of magnitude in 65 days. While previous samples of ancient bacteria are clouded by contamination concerns or disputes over their age, there have been other samples of ancient-yet-alive bacteria discovered, including in 15 million-year-old sediment just last year.
But the JAMSTEC team’s bacteria move the goalposts dramatically, not just reshaping how we consider life on Earth, but also beyond it. The study shows that “microbial life is very persistent, and often finds a way to survive,” Virginia Edgcomb, a microbial ecologist at the Woods Hole Oceanographic Institution. And that could include our solar neighbors or even exoplanets, extraterrestrial environments once assumed to be barren.
