Mineralogy and Microbial Diversity of the Microbialites in the Hypersaline Storr's Lake, the Bahamas
Microbialites found in the low-light-intensity, hypersaline waters of Storr's Lake (SL), San Salvador Island, the Bahamas, were investigated with respect to their morphology, mineralogy, and microbial diversity. Previously described microbialite morphologies, as well as a newly identified "multi-cuspate" morphology, were observed at various depths. Electron microscopy analysis revealed the presence of angular, blocky, and needle-shaped crystals with mineralized cyanobacterial filaments and remains of exopolymeric substances. X-ray diffraction studies confirmed the presence of both Mg-calcite and aragonite in the plateau-mushroom and pinnacle mound microbialites, whereas only Mg-calcite was identified in the other microbialite morphotypes. A comprehensive molecular analysis using barcoded pyrosequencing of five different microbial mat communities identified at least 12 dominant bacterial phyla. Cyanobacteria were generally low in abundance and ranged from ~0.01% in the deeper pinnacle mounds to ~3.2% in the shallow calcareous knobs. Other photosynthetic members included green nonsulfur bacteria of the phylum Chloroflexi and purple sulfur bacteria of the class Gammaproteobacteria. All mat types contained significant amounts of sulfate-reducing and dehalogenating bacteria. The low light intensity reaching the deeper microbialites, the lack of dominant cyanobacteria, and the abundance of sulfate reducers and Chloroflexi collectively suggest that sulfate reduction and anoxygenic photosynthetic processes influence the carbonate biomineralization process in these systems.
V. G. Paul et al., "Mineralogy and Microbial Diversity of the Microbialites in the Hypersaline Storr's Lake, the Bahamas," Astrobiology, vol. 16, no. 4, pp. 282-300, Mary Ann Liebert Inc., Apr 2016.
The definitive version is available at http://dx.doi.org/10.1089/ast.2015.1326
Geosciences and Geological and Petroleum Engineering
Keywords and Phrases
Biomineralization; Microbial Diversity; Microbial Mats; Bahamas; Biodiversity; Lake; Microbiology; Salinity; Water Microbiology
International Standard Serial Number (ISSN)
Article - Journal
© 2016 Mary Ann Liebert Inc., All rights reserved.