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Title: Microbial Diversity and Biomarker Analysis of Modern Freshwater Microbialites from Laguna Bacalar, Mexico

Abstract

Laguna Bacalar is a sulfate-rich freshwater lake on the Yucatan Peninsula that hosts large microbialites. High sulfate concentrations distinguish Laguna Bacalar from other freshwater microbialite sites such as Pavilion Lake and Alchichica, Mexico, as well as from other aqueous features on the Yucatan Peninsula. While cyanobacterial populations have been described here previously, this study offers a more complete characterization of the microbial populations and corresponding biogeochemical cycling using a three-pronged geobiological approach of microscopy, high-throughput DNA sequencing, and lipid biomarker analyses. We identify and compare diverse microbial communities of Alphaproteobacteria, Deltaproteobacteria, and Gammaproteobacteria that vary with location along a bank-to-bank transect across the lake, within microbialites, and within a neighboring mangrove root agglomeration. In particular, sulfate-reducing bacteria are extremely common and diverse, constituting 7%-19% of phylogenetic diversity within the microbialites, and are hypothesized to significantly influence carbonate precipitation. In contrast, Cyanobacteria account for less than 1% of phylogenetic diversity. The distribution of lipid biomarkers reflects these changes in microbial ecology, providing meaningful biosignatures for the microbes in this system. Polysaturated short-chain fatty acids characteristic of cyanobacteria account for <3% of total abundance in Laguna Bacalar microbialites. By contrast, even short-chain and monounsaturated short-chain fatty acids attributable to both Cyanobacteria andmore » many other organisms including types of Alphaproteobacteria and Gammaproteobacteria constitute 43%-69% and 17%-25%, respectively, of total abundance in microbialites. While cyanobacteria are the largest and most visible microbes within these microbialites and dominate the mangrove root agglomeration, it is clear that their smaller, metabolically diverse associates are responsible for significant biogeochemical cycling in this microbialite system.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
Northwestern University
OSTI Identifier:
1461427
DOE Contract Number:  
AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Geobiology; Journal Volume: 16
Country of Publication:
United States
Language:
English

Citation Formats

Johnson, Dana B., Beddows, Patricia A., Flynn, Theodore M., and Osburn, Magdalena R. Microbial Diversity and Biomarker Analysis of Modern Freshwater Microbialites from Laguna Bacalar, Mexico. United States: N. p., 2018. Web. doi:10.1111/gbi.12283.
Johnson, Dana B., Beddows, Patricia A., Flynn, Theodore M., & Osburn, Magdalena R. Microbial Diversity and Biomarker Analysis of Modern Freshwater Microbialites from Laguna Bacalar, Mexico. United States. doi:10.1111/gbi.12283.
Johnson, Dana B., Beddows, Patricia A., Flynn, Theodore M., and Osburn, Magdalena R. Tue . "Microbial Diversity and Biomarker Analysis of Modern Freshwater Microbialites from Laguna Bacalar, Mexico". United States. doi:10.1111/gbi.12283. https://www.osti.gov/servlets/purl/1461427.
@article{osti_1461427,
title = {Microbial Diversity and Biomarker Analysis of Modern Freshwater Microbialites from Laguna Bacalar, Mexico},
author = {Johnson, Dana B. and Beddows, Patricia A. and Flynn, Theodore M. and Osburn, Magdalena R.},
abstractNote = {Laguna Bacalar is a sulfate-rich freshwater lake on the Yucatan Peninsula that hosts large microbialites. High sulfate concentrations distinguish Laguna Bacalar from other freshwater microbialite sites such as Pavilion Lake and Alchichica, Mexico, as well as from other aqueous features on the Yucatan Peninsula. While cyanobacterial populations have been described here previously, this study offers a more complete characterization of the microbial populations and corresponding biogeochemical cycling using a three-pronged geobiological approach of microscopy, high-throughput DNA sequencing, and lipid biomarker analyses. We identify and compare diverse microbial communities of Alphaproteobacteria, Deltaproteobacteria, and Gammaproteobacteria that vary with location along a bank-to-bank transect across the lake, within microbialites, and within a neighboring mangrove root agglomeration. In particular, sulfate-reducing bacteria are extremely common and diverse, constituting 7%-19% of phylogenetic diversity within the microbialites, and are hypothesized to significantly influence carbonate precipitation. In contrast, Cyanobacteria account for less than 1% of phylogenetic diversity. The distribution of lipid biomarkers reflects these changes in microbial ecology, providing meaningful biosignatures for the microbes in this system. Polysaturated short-chain fatty acids characteristic of cyanobacteria account for <3% of total abundance in Laguna Bacalar microbialites. By contrast, even short-chain and monounsaturated short-chain fatty acids attributable to both Cyanobacteria and many other organisms including types of Alphaproteobacteria and Gammaproteobacteria constitute 43%-69% and 17%-25%, respectively, of total abundance in microbialites. While cyanobacteria are the largest and most visible microbes within these microbialites and dominate the mangrove root agglomeration, it is clear that their smaller, metabolically diverse associates are responsible for significant biogeochemical cycling in this microbialite system.},
doi = {10.1111/gbi.12283},
journal = {Geobiology},
number = ,
volume = 16,
place = {United States},
year = {Tue May 01 00:00:00 EDT 2018},
month = {Tue May 01 00:00:00 EDT 2018}
}