Deep, dark fractures reaching far down into the oldest rocks on Earth may seem about as hospitable to life as outer space, but some estimates suggest that microbes dwelling deep in the Earth's crust account for the majority of microbial life.
Deep, dark fractures reaching far down into the oldest rocks on Earth may seem about as hospitable to life as outer space, but some estimates suggest that microbes dwelling deep in the Earth's crust account for the majority of microbial life. These underground lifeforms, which make up what's known as the deep biosphere, could account for as much as 20% of all biomass on Earth.
These ecosystems host microbial lineages that are of interest for understanding the origin and evolution of life on our planet but remain the least explored and understood ecosystems on Earth, according to the authors of a new study that takes a closer look at how deep habitats changed during Earth's tumultuous past.
"Understanding the history of the deep biosphere can provide insight into the evolution of life on Earth," said Peter Reiners, a professor of geosciences and associate dean of the University of Arizona College of Science, who co-authored the paper with Henrik Drake, an associate professor at the Linnaeus University in Sweden. "This requires understanding the complex evolution of habitable conditions in these underground environments, but such assessment had not been presented until now."
Read more at: University of Arizona
Calcite, a mineral related to the presence of microorganisms, was recovered from a deep fracture in Swedish granite. Reiners and Drake used mineral-related biosignatures such as these to look for ancient habitable conditions deep inside the Earth. (Photo Credit: Henrik Drake/Linnaeus University)
