Marine stromatolites are formed by the interactions of several key bacterial groups, which precipitate repeating layers (laminae) of calcium carbonate (CaCO3). During 70% of the time life has occupied earth, stromatolites were a dominant biological community. Their associated microbial communities have played a significant role in carbon sequestration, preservation, and cycling during the evolution of life. Present-day marine stromatolite communities consist of cyanobacteria (both free-living filamentous cyanobacteria and coccoid endoliths), sulfate reducers (SRB), sulfur-oxidizers (SOB), and aerobic heterotrophs (including fermenters). The interactions of these key groups drive the organized precipitation of CaCO3. The marine stromatolite system, therefore, provides an ideal platform from which to understand fundamental microbially mediated precipitation and carbon transformations, and to probe microbial interactions.
The sequencing of six proposed strains of bacteria from stromatolites will provide a crucial genomic foundation of ‘structure/function’ for understanding carbonate lithification, carbon cycling, and chemical communication. The broader importance of this work lies in understanding the biofilm-mediated processes within the mats; a knowledge that can be extrapolated to biofilms in many other systems including those involved in health and disease (kidney, gall stones, and bone formation), hospital-acquired (nosocomial) infections, biofouling, microbially mediated metal corrosion, and mineral formation.
Principal Investigator: Alan w. Decho (Univ. of South Carolina)