PNNL

Organic matter found in vast quantities in oxygen-starved floodplains would yield only minimal energy for hungry microorganisms, which spurn the meal, researchers show in a study published this week in Nature Geoscience.

The soils beneath our feet contain more carbon than all of the world's plants and the atmosphere combined, and knowing the fate of this organic matter is crucial to understand the future of our planet. The new findings, made by a team which includes Malak Tfaily of the Environmental Molecular Sciences Laboratory, a Department of Energy Office of Science user facility at DOE's Pacific Northwest National Laboratory, helps explain why microbes sometimes don't break down all the available carbon.

Tfaily's work at EMSL was instrumental in showing that the available carbon left by the microbes in deep sediment layers is a poor source of energy that would have required more energy from the microbes to degrade than they would have received in return. The team made the findings by using high-resolution mass spectrometry to analyze core samples of buried sediments from four floodplains in the upper Colorado River Basin in the states of Colorado and New Mexico.

More information about the study, which was led by researchers at Stanford University, is available through Stanford's news release.