Extremophile microbes found thriving half a mile beneath the seafloor


Valued Senior Member

Every time we think we’ve figured out the limits of where life can exist, we discover extremophile organisms thriving under conditions we’d previously ruled out. The latest example comes from studies of rock cores drilled from the floor of the Indian Ocean, where microbes were discovered alive and well under almost half a mile of rock.

The discoveries were made as part of the International Ocean Discovery Program (IODP), which studies samples of rock and sediment taken from beneath the seafloor. Normally, it’s to investigate the historic climate records preserved there, but in this case an international team of scientists found evidence of life.

The researchers scoured rock samples taken from the lower oceanic crust, searching for genetic material and organic molecules. When they found it, they performed cell counts and then grew samples in lab dishes. All together, these methods revealed a relatively small but diverse population of microbes living as deep as 2,600 feet (792 m) below the ocean floor.

“They are tiny, around 1 micrometer,” says Jason Sylvan, an author of the study. “We can’t tell the age, but assume them to be currently extant, so not necessarily old, but in an environment that is extreme and subsurface. We believe this is the first research to show active microbes in this environment and to be able to describe their lifestyles using such a broad array of data streams.”


more at link.......