See more from this Division: Topical Sessions
See more from this Session: Biofilms and Biomineralization: Evidence from Ancient and Modern Systems
Abstract:
Given that hyperthermophilic microbial biofilms consist primarily of filamentous bacteria in silica-depositing hot springs, these organisms tend to have the greatest impact on geyserite fabrics and stromatolite structures. Hyperthermophilic biofilms, their corresponding sinters, and substratums colonized by such biofilms were characterized by a variety of imaging, diffraction, and spectroscopic methods. We have found that differences in the relative timing of mineralization of the various components of these biofilms are key to preserving evidence of the presence and behavior of microbial populations in the corresponding siliceous sinter deposits.
Key points include, early mineralized microbial filaments act as a scaffolding within any one lamination of the stromatolitic deposits. Though secondary infilling tends to mask microbial input, specimen etching confirms the architectural role of the filamentous structures. The intercalation of abiotic and biogenic laminations in subaerial regimes results from the episodic colonization of sinter surfaces when mineral accretion rates are high. The initial colonization and replication of filamentous cells on geyserite surfaces defines the base of biogenic sinter laminae, whereas the production of copious amounts of EPS define laminae surfaces. The distribution of organics in geyserite laminae reflect these distinct concentration differences in the distribution of microbial cells and extracellular remains in these types of stromatolites.
See more from this Division: Topical Sessions
See more from this Session: Biofilms and Biomineralization: Evidence from Ancient and Modern Systems