CHAMPAIGN, Ill. Scientists studying microbial communities and the growth of sedimentary rock at Mammoth Hot Springs in Yellowstone National Park have made a surprising discovery about the geological record of life and the environment.
Their discovery could affect how certain sequences of sedimentary rock are dated, and how scientists might search for evidence of life on other planets.
We found microbes change the rate at which calcium carbonate precipitates, and that rate controls the chemistry and shape of calcium carbonate crystals, said Bruce Fouke, a professor of geology and of molecular and cellular biology at the University of Illinois.
In fact, the precipitation rate can more than double when microbes are present, Fouke and his colleagues report in a paper accepted for publication in the Geological Society of America Bulletin.
The researchers findings imply changes in calcium carbonate mineralization rates in the rock record may have resulted from changes in local microbial biomass concentrations throughout geologic history.
A form of sedimentary rock, calcium carbonate is the most abundant mineral precipitated on the surface of Earth, and a great recorder of life.
As calcium carbonate is deposited, it leaves a chemical fingerprint of the animals and environment, the plants and bacteria that were there, said Fouke, who also is affiliated with the universitys Institute for Genomic Biology.
The extent to which microorganisms influence calcium carbonate precipitation has been one of the most controversial issues in the field of carbonate sedimentology and geochemistry. Separating biologically precipitated calcium carbonate from non-biologically precipitated calcium carbonate is difficult.
Foukes research team has spent 10 years quantifying the physical, chemical and biological aspects of the hot springs environment. The last step in deciphering the calcium carbonate record was performing an elaborate field experiment, which
|Contact: James E. Kloeppel|
University of Illinois at Urbana-Champaign