Metagenomic and Stable Isotopic Analyses of Modern Freshwater Microbialites in Cuatro Ciénegas, Mexico

Mya Breitbart, Ana Maria Hoare, Anthony G. Nitti, Janet Siefert, Matthew Haynes, Elizabeth Dinsdale, Robert Edwards, Valeria Souza, Forest Rohwer, David Hollander

Research output: Contribution to journalArticlepeer-review

Abstract

<p> Ancient biologically mediated sedimentary carbonate deposits, including stromatolites and other microbialites, provide insight into environmental conditions on early Earth. The primary limitation to interpreting these records is our lack of understanding regarding microbial processes and the preservation of geochemical signatures in contemporary microbialite systems. Using a combination of metagenomic sequencing and isotopic analyses, this study describes the identity, metabolic potential and chemical processes of microbial communities from living microbialites from Cuatro Ci&eacute;negas, Mexico. Metagenomic sequencing revealed a diverse, redox&hyphen;dependent microbial community associated with the microbialites. The microbialite community is distinct from other marine and freshwater microbial communities, and demonstrates extensive environmental adaptation. The microbialite metagenomes contain a large number of genes involved in the production of exopolymeric substances and the formation of biofilms, creating a complex, spatially structured environment. In addition to the spatial complexity of the biofilm, microbial activity is tightly controlled by sensory and regulatory systems, which allow for coordination of autotrophic and heterotrophic processes. Isotopic measurements of the intracrystalline organic matter demonstrate the importance of heterotrophic respiration of photoautotrophic biomass in the precipitation of calcium carbonate. The genomic and stable isotopic data presented here significantly enhance our evolving knowledge of contemporary biomineralization processes, and are directly applicable to studies of ancient microbialites.</p>
Original languageAmerican English
JournalEnvironmental Microbiology
Volume11
DOIs
StatePublished - Jan 1 2009

Disciplines

  • Life Sciences

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