Microbial Community Structures of Novel Icelandic Hot Spring Systems Revealed by PhyloChip G3 Analysis

Abstract

Microbial community profiles of recently formed hot spring systems ranging in temperatures from 57°C to 100°C and pH values from 2 to 4 in Hverager+i (Iceland) were analyzed with PhyloChip G3 technology. In total, 1173 bacterial operational taxonomic units (OTUs) spanning 576 subfamilies and 38 archaeal OTUs covering 32 subfamilies were observed. As expected, the hyperthermophilic (*100°C) spring system exhibited both low microbial biomass and diversity when compared to thermophilic (*60°C) springs. Ordination analysis revealed distinct bacterial and archaeal diversity in geographically distinct hot springs. Slight variations in temperature (from 57°C to 64°C) within the interconnected pools led to a marked fluctuation in microbial abundance and diversity. Correlation and PERMANOVA tests provided evidence that temperature was the key environmental factor responsible for microbial community dynamics, while pH, H 2 S, and SO 2 influenced the abundance of specific microbial groups. When archaeal community composition was analyzed, the majority of detected OTUs correlated negatively with temperature, and few correlated positively with pH.

A Laboratory of Extremophiles: Iceland Coordination Action for Research Activities on Life in Extreme Environments (CAREX) Field Campaign

“…More detailed results of the PhyloChip analyses are presented elsewhere by Krebs et al . 2013 [ 20 ]. The PhyloChip results are in correlation with the ATP and qPCR results, and again, the low diversity at site P2 may be explained by a slightly higher temperature, compared to P1 and P2 samples.…”

“…Each 25 μL reaction consisted of 12.5 μL of BioRad 2X iQ SYBR Green Supermix, 1 μL of each of forward and reverse oligonucleotide primer and 1 μL of template DNA. Reaction conditions were as follows: 95 °C denaturation for 3 min, followed by 35 cycles of denaturation at 95 °C for 15 s and a combined annealing and extension at 55 °C for 35 s [ 20 ].…”

“…An OTU was considered present in the sample when 90% or more of its assigned probe pairs for its corresponding probe set were positive (positive fraction >0.90). For each sample, all OTU intensity measurements were normalized by a scaling factor, such that the overall chip intensity was equal among each PhyloChip [ 20 ].…”

Thermophiles as a Promising Source of Exopolysaccharides with Interesting Properties

“…Among the disadvantages of exploring hot spring potential are the low biomass and respectively low EPS synthesis by thermophiles (Krebs et al 2014 ). Additionally, the proportion of microorganisms reluctant to cultivation-based approaches is very high in extreme environments (Lorenz et al 2002 ).…”

A vida microbiana em um vulcão antártico: diversidade e adaptação procariótica na Ilha <i>Deception</i>.

“…Embora o número de sequências para Archaea tenha sido consideravalmente baixo em comparação com o número de sequências de Bacteria, a curva de rarefação estimou que provavelmente o esforço amostral foi suficiente para avaliar a diversidade real no ambiente (com excessão das amostras das geleiras). De qualquer modo, milhares de sequências foram obtidas neste trabalho para avaliar a composição e diversidade do Domínio Archaea em Deception, em contraste com as 12 sequências detectadas porKrebs et al, (2014) estudaram a diversidade microbiana em hot springs da Islândia (~100 o C) através de PhyloChip, e detectaram dentro de Archaea, 20 OTUs relacionadas Deception foram compostas por arqueias halofílicas do gênero Haloferax (80 o C) e nitrificantes do gênero Nitrosopumilus (50 e 10 o C) e do gênero Nitrososphaera (10 o C). As amostras da geleira de Fumarole Bay, foram compostas essencialmente por metanogênicas (~0 o C).…”