The deep biosphere—the realm of sediments far below the seafloor—harbors a vast ecosystem of bacteria, archaea, and fungi that are actively metabolizing, proliferating, and moving, according a new study by scientists at Woods Hole Oceanographic Institution (WHOI) and the University of Delaware (UD).
“This is the first molecular evidence for active cell division in the deep biosphere,” says Orsi. Previous studies and models had suggested cells were alive, but whether the cells were actually dividing or not had remained elusive.
The finding of so much activity in the deep biosphere has implications for our understanding of global biogeochemical cycles, say the study’s authors.
“Cells are very abundant there, but they do not have high activity levels,” says WHOI microbial ecologist Virginia Edgcomb. “But it’s a huge biosphere, and when you do the math, you see we’re talking about a potentially significant contribution. Carbon is being turned over, and that has important implications for models of carbon and nitrogen cycling.”
The researchers analyzed messenger RNA (mRNA) from different depths in a sediment core collected off the coast of Peru in 2002 during Leg 201 of the Ocean Drilling Program. Their work was published in Nature on June 12.
This first glimpse into the workings of the heretofore hidden ecosystem was made possible by the first successful extraction of total mRNA, or the “metatranscriptome,” from the deep biosphere.
Messenger RNA is highly sought-after by microbial ecologists because its presence indicates that the cells that made it are alive, and because it carries the instructions for the proteins the cells are making. That gives researchers valuable information about the biochemical mechanisms and processes the organisms are using to function.
Read more at: Phys.org