Life, something that we living things have, and it’s reasonably good to mention we have infiltrated the Earth. Microorganisms too are part of living beings and that they just keep surprising us by turning out in unexpected times and extreme places.
The latest place they’ve shown up is below the seafloor, in Earth’s lower crust and thus proves that life can find the most straightforward way even under the foremost extreme and remote conditions.
Rock cores drilled from an undersea mountain in the Indian Ocean revealed that bacteria, fungi, and single-celled organisms called archaea live in cracks and fissures in dense rocks of the ocean’s lower crust.
Edgcomb, marine geologist, Jiangtao Li from Tongji University in China and colleagues, analyzed rock samples drilled from Atlantis Bank, an undersea ridge within the Indian Ocean.
The latest research, published today in the journal Nature, suggests that survival within the deep biosphere depends on underground fluid flow.
As seawater goes deep into the crust, it travels through cracks within the rocks. This fluid contains organic matter from the ocean, and thus the team found signs of life clustered around these nutrients.
The organisms include Chroococcidiopsis, species of cyanobacteria known for their ability to survive in extreme conditions (extremophiles), and Pseudomonas bacteria, known for the various other ways they metabolize energy. “These organisms live in a hostile environment far beneath the ocean floor.” noted biochemist Paraskevi Mara from WHOI. A number of those are autotrophs organisms that prepare their food.
Although most of these organisms are found in other extreme environments, underground life relies on both fixing chemicals for energy and co-opting organic matter floating within the fluid.
Steven D’Hondt, a professor at the University of Rhode Island who hasn’t involved the research, said this “runs counter to straightforward assumptions about sub-seafloor crustal life.” He added that the readiness of that community to consume organic matter suggests that it’s metabolically linked to the broader world.
The research team extracted cores from the undersea mountain Atlantis Bank where the lower crust is exposed to the ocean floor, which is unusual.
The researchers also determined that several microbes depend on breaking down organic matter for sustenance. They would mostly feed on scraps of organic molecules. Some microbes even have the flexibility to store carbon in their cells, while others can extract it from tough molecules called polyaromatic hydrocarbons.
The latest study shows that “life finds a way,” said Jennifer Biddle, an associate professor at the University of Delaware who did not participate in the study.
Whether life exists in similar geological places in other parts of the world is yet to be found. Still, “the lower ocean crust is one amongst the last frontiers of the exploration for life on Earth,” Edgcomb said.
“If you look at the amount of the deep biosphere, including the lower oceanic crust, even at an awfully slow rate, it could equate to significant amounts of carbon,” said Edgecomb.
They have published the research in Nature.