A research team from the Japan Sea and Earth Science and Technology Agency (JAMSTEC) and the University of Rhode Island Graduate School of Oceanography have collected samples of microbes from the seafloor up to 100 million years old that have been revived, and have multiplied, under laboratory conditions.
The samples were obtained on an expedition to Gyre in the South Pacific, as published in Nature Communications .
From the time of the dinosaurs
On board the JOIDES Resolution research vessel, the team drilled numerous sediment cores 100 meters below the seafloor and almost 6,000 meters below the ocean surface .
On the seafloor, there are layers of sediment consisting of marine snow (organic debris continuously coming from the sea surface), dust, and particles carried by the wind and ocean currents. Small life forms like microbes get trapped in this sediment. As the lead author of the cited study, Yuki Morono , JAMSTEC lead scientist, explains:
Our main question was whether life could exist in such a nutrient-limited environment or if it was a lifeless zone. And we wanted to know how long microbes could sustain their life in the absence of food.
The results showed that, instead of being fossilized remains of life, the microbes in the sediment had survived and were capable of growing and dividing .
At first I was skeptical, but we found that up to 99.1% of the microbes in sediments deposited 101.5 million years ago were still alive and ready to eat.
What is most extraordinary about this study is that it shows that there are no limits to life in old ocean sediment, so a similar approach could be applied to other questions about the geological past. Ultimately, the subsoil is an excellent location to explore the limits of life on Earth .