Life doesn’t get much stranger:
For decades, scientists have gathered ancient sediment samples from below the seafloor to better understand past climates, plate tectonics and the deep marine ecosystem. In a new study published in Nature Communications, researchers reveal that given the right food in the right laboratory conditions, microbes collected from sediment as old as 100 million years can revive and multiply, even after laying dormant since large dinosaurs prowled the planet.
The research team behind the new study, from the Japan Agency for Marine-Earth Science and Technology (JAMSTEC), the URI Graduate School of Oceanography, the National Institute of Advanced Industrial Science and Technology, the Kochi University and Marine Works Japan, gathered the ancient sediment samples ten years ago during an expedition to the South Pacific Gyre, the part of the ocean with the lowest productivity and fewest nutrients available to fuel the marine food web.
“Our main question was whether life could exist in such a nutrient-limited environment or if this was a lifeless zone,” said the paper’s lead author Yuki Morono, senior scientist at JAMSTEC. “And we wanted to know how long the microbes could sustain their life in a near-absence of food.” …
Morono was initially taken aback by the results. “At first I was skeptical, but we found that up to 99.1% of the microbes in sediment deposited 101.5 million years ago were still alive and were ready to eat,” he said.
With the newly developed ability to grow, manipulate and characterize ancient microorganisms, the research team is looking forward to applying a similar approach to other questions about the geological past. According to Morono, life for microbes in the subseafloor is very slow compared to life above it, and so the evolutionary speed of these microbes will be slower. “We want to understand how or if these ancient microbes evolved,” he said. “This study shows that the subseafloor is an excellent location to explore the limits of life on Earth.”University of Rhode Island, “Deep sea microbes dormant for 100 million years are hungry and ready to multiply” at ScienceDaily
Well, just a minute. If they were in suspended animation for 100 million years, it’s not likely they were evolving at all. We are looking at microbes from 100 million years ago.
Jurassic Park under the microscope.
At Science Magazine some questions are raised:
Genetic analysis of the microbes revealed they belonged to more than eight known bacterial groups, many of which are commonly found elsewhere in saltwater where they play important roles in breaking down organic matter. “It suggests that learning to survive under conditions of extreme energy limitation is a widespread ability,” Nealson says, one that may have evolved early, when there was not much for microbes to feed on. “It may have been a very handy survival trick.”
The researchers don’t know what the gyre microbes have been doing all these millions of years. Most of the species they found do not form spores, which are an inactive life stage that some bacteria form in unfavorable conditions. It could be the bacteria have been dividing very slowly all this time, which would make those isolated in this study the distant descendants of ancestors millions of years old.
But there’s so little food in the deep-sea sediments that any microbes there could most likely do little more than repair any damaged molecules.Elizabeth Pennisi, “Scientists pull living microbes, possibly 100 million years old, from beneath the sea” at Science
One researcher termed te 100-million-year survival “insane” and speculated that there may be an unnoticed form of energy down there, perhaps radioactivity.
Well, we live in a strange world, it seems …