Credit: CC0 Public Domain Microbial communities living in deep aquatic sediments have adapted to survive on degraded organic matter, according to a study published in Applied and Environmental Microbiology and coauthored by professors at the University of Tennessee, Knoxville.
"There are microbes living in deep ocean sediments eating carbon, like proteins and carbohydrates, that is hundreds of years old," said Andrew Steen, lead author of the study and assistant professor of environmental geology at UT.
To better understand how these microorganisms access this food, researchers tested different types of peptidases—digestive enzymes that work to degrade proteins—in sediment cores from the White Oak River estuary in North Carolina.
Using DNA analysis of the microbes in these sediments, and by measuring peptidases, researchers evaluated how these microorganisms metabolize with little access to fresh organic matter.
Steen's study gives insight into how these subsurface microbial communities begin the process of degrading organic carbon in such environments.
"Our study shows that, in some sense, subsurface microbes are happy to be where they are—or at least they're well adapted to a terrible environment," said Steen.
D. Steen et al, Kinetics and identities of extracellular peptidases in subsurface sediments of the White Oak River Estuary, NC, Applied and Environmental Microbiology (2019).