A Study of the Microbial Spatial Heterogeneity of Bahamian Thrombolites Using Molecular, Biochemical, and Stable Isotope Analyses

Artemis S. Louyakis, Jennifer M. Mobberley, Brooke E. Vitek, Pieter T. Visscher, Paul D. Hagan, R. Pamela Reid, Reinhard Kozdon, Ian J. Orland, John W. Valley, Noah J. Planavsky, Giorgio Casaburi, Jamie S. Foster

Research output: Contribution to journalArticle

16 Scopus citations

Abstract

Thrombolites are buildups of carbonate that exhibit a clotted internal structure formed through the interactions of microbial mats and their environment. Despite recent advances, we are only beginning to understand the microbial and molecular processes associated with their formation. In this study, a spatial profile of the microbial and metabolic diversity of thrombolite-forming mats of Highborne Cay, The Bahamas, was generated by using 16S rRNA gene sequencing and predictive metagenomic analyses. These molecular-based approaches were complemented with microelectrode profiling and in situ stable isotope analysis to examine the dominant taxa and metabolic activities within the thrombolite-forming communities. Analyses revealed three distinctive zones within the thrombolite-forming mats that exhibited stratified populations of bacteria and archaea. Predictive metagenomics also revealed vertical profiles of metabolic capabilities, such as photosynthesis and carboxylic and fatty acid synthesis within the mats that had not been previously observed. The carbonate precipitates within the thrombolite-forming mats exhibited isotopic geochemical signatures suggesting that the precipitation within the Bahamian thrombolites is photosynthetically induced. Together, this study provides the first look at the spatial organization of the microbial populations within Bahamian thrombolites and enables the distribution of microbes to be correlated with their activities within modern thrombolite systems.

Original languageEnglish (US)
Pages (from-to)413-430
Number of pages18
JournalAstrobiology
Volume17
Issue number5
DOIs
StatePublished - May 2017

Keywords

  • Metagenome
  • Microbial diversity
  • Microbialites
  • Stable isotopes
  • Thrombolites

ASJC Scopus subject areas

  • Agricultural and Biological Sciences (miscellaneous)
  • Space and Planetary Science

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    Louyakis, A. S., Mobberley, J. M., Vitek, B. E., Visscher, P. T., Hagan, P. D., Reid, R. P., Kozdon, R., Orland, I. J., Valley, J. W., Planavsky, N. J., Casaburi, G., & Foster, J. S. (2017). A Study of the Microbial Spatial Heterogeneity of Bahamian Thrombolites Using Molecular, Biochemical, and Stable Isotope Analyses. Astrobiology, 17(5), 413-430. https://doi.org/10.1089/ast.2016.1563