The influence of temperature and pH on bacterial community composition of microbial mats in hot springs from Costa Rica

We used the 16S rRNA gene pyrosequencing approach to investigate the microbial diversity and community composition in several Costa Rican hot springs alongside the latitudinal axis of the country, with a range of temperatures (37–63°C), pH (6–7.5) and other geochemical conditions. A principal component analyses of the physicochemical parameters showed the samples were separated into three geochemically distinct habitats associated with the location (North, Central, and South). Cyanobacteria and Chloroflexi comprised 93% of the classified community, the former being the most abundant phylum in all samples except for Rocas Calientes 1, (63°C, pH 6), where Chloroflexi and Deinococcus‐Thermus represented 84% of the OTUs. Chloroflexi were more abundant as temperature increased. Proteobacteria, Bacteriodetes and Deinococcus‐Thermus comprised 5% of the OTUs represented. Other Phyla were present in very small percentages ( 6.6 from samples with pH < 6.4. Thus, both pH and temperature were relevant for community composition even within the moderate ranges of variables studied. These results provide a basis for an understanding of the physicochemical influences in moderately thermophilic microbial mats.Universidad de Costa Rica/[801‐B1‐542]/UCR/Costa RicaFundación Costa Rica Estados Unidos para la Cooperación/[/1-(1E)-10]/CRUSA/Costa RicaFondo Nacional de Desarrollo Científico y Tecnológico/[1110696]FONDECYT/ChileFondo Nacional de Desarrollo Científico y Tecnológico/[1150171]FONDECYT/ChileConsejo Superior de Investigaciones Científicas/[COOPB20096]/CSIC/EspañaConsejo Superior de Investigaciones Científicas/[2010CROO08]/CSIC/EspañaFondo de Financiamiento de Centros de Investigación en Áreas Prioritarias/[15110009]/Fondap/ChileSpanish Ministry of Science and Innovation/[CTM2016-80095-C2-1-R]/MICINN/EspañaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Biología Celular y Molecular (CIBCM)UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela Centroamericana de Geologí