Beneath Earth’s surface lies a kingdom of undiscovered microscopic life. These “intraterrestrials” survive in some of the harshest conditions on the planet — and scientists are hunting for these microbes.
In this excerpt from “Intraterrestrials: Discovering the Strangest Life on Earth” (Princeton University Press, 2025), author Karen G. Lloyd, a microbial biogeochemist at the University of Southern California Dornsife, examines the idea of evolution among life that can survive for hundreds of thousands — if not millions — of years in a dormant state and what it might be waiting for to “wake up.”
How does one evolve to stop growing for thousands of years? Recent work suggests that microbes buried deep in oceanic seafloor sediments may be doing just that. Such organisms can be referred to as intraterrestrials, small microorganisms living inside Earth’s crust all around the globe. To answer this tough evolutionary question, first we have to think about what these organisms would experience in their lifetimes. These slow organisms wouldn’t be concerned about the length of a day. They’re buried so deep that they can’t detect the sun anyway. They probably wouldn’t even notice a change in season.
“Writer Fuel” is a series of cool real-world stories that might inspire your little writer heart. Check out our Writer Fuel page on the LimFic blog for more inspiration.
