Journal Article
Applied and Environmental Microbiology, vol. 86, iss. 7, 2020
Authors
Laurey Steinke, Gordon W. Slysz, Mary S. Lipton, Christian Klatt, James J. Moran, Margie F. Romine, Jason M. Wood, Gordon Anderson, Donald A. Bryant, David M. Ward, Robert M. Kelly
Abstract
Yellowstone hot spring mats have been studied as natural models for understanding microbial community ecology and as modern analogs of stromatolites, the earliest community fossils on Earth. Stable-isotope probing of proteins (Pro-SIP) permitted short-term interrogation of the taxa that are involved in the important process of light-driven C
i
fixation in this highly active community and will be useful in linking other metabolic processes to mat taxa. Here, evidence is presented that
Roseiflexus
spp., which use the 3-hydroxypropionate bi-cycle, are active in C
i
fixation. Because this pathway imparts a lower degree of selection of isotopically heavy C
i
than does the Calvin-Benson-Bassham cycle, the results suggest a mechanism to explain why the natural abundance of
13
C in mat biomass is greater than expected if only the latter pathway were involved. Understanding how mat community members influence the
13
C/
12
C ratios of mat biomass will help geochemists interpret the
13
C/
12
C ratios of organic carbon in the fossil record.
