Archaeal and bacterial diversity in acidic to circumneutral hot springs in the Philippines

Abstract

The microbial diversity was investigated in sediments of six acidic to circumneutral hot springs (Temperature: 60-92 °C, pH 3.72-6.58) in the Philippines using an integrated approach that included geochemistry and 16S rRNA gene pyrosequencing. Both bacterial and archaeal abundances were lower in high-temperature springs than in moderate-temperature ones. Overall, the archaeal community consisted of sequence reads that exhibited a high similarity (nucleotide identity > 92%) to phyla Crenarchaeota, Euryarchaeota, and unclassified Archaea. The bacterial community was composed of sequence reads moderately related (nucleotide identity > 90%) to 17 phyla, with Aquificae and Firmicutes being dominant. These phylogenetic groups were correlated with environmental conditions such as temperature, dissolved sulfate and calcium concentrations in spring water, and sediment properties including total nitrogen, pyrite, and elemental sulfur. Based on the phylogenetic inference, sulfur metabolisms appear to be key physiological functions in these hot springs. Sulfobacillus (within phylum Firmicutes) along with members within Sulfolobales were abundant in two high-temperature springs (> 76 °C), and they were hypothesized to play an important role in regulating the sulfur cycling under high-temperature conditions. The results of this study improve our understanding of microbial diversity and community composition in acidic to circumneutral terrestrial hot springs and their relationships with geochemical conditions.

Taxonomic and Functional Diversity Provides Insight into Microbial Pathways and Stress Responses in the Saline Qinghai Lake, China

“…A Horiba multi-parameter meter (W-20XD Series, HORIBA, Kyoto, Japan) was used to measure in-situ environmental parameters of the water including; temperature, pH, conductivity, dissolved oxygen (DO), depth, chloride (Cl − ), and salinity at both sites. Concentrations of major ions (i.e., sulfide, sulfate, silica, nitrite, nitrate, ferrous iron, and ammonia) in the filtered water of both sites were measured using a HACH colorimeter (model CEL 850, HACH Chemical Co., Iowa, USA) as previously described [20]. Filters collected for microbial analysis were placed on dry ice immediately after filtering of lake water from each site, and stored at −80 ° C in the laboratory until DNA and RNA extractions were conducted.…”

“…The resulting RNA was purified and concentrated using the RNeasyMinElute Cleanup kit (Qiagen, Valencia, CA, USA) [22]. Genomic DNA was extracted from the other half of the filter using the FastDNA Spin Kit (MP Biomedical, OH, USA) as previously described [20]. The amount of DNA that was extracted from sites B and E was 14.6 and 13.8 ng µl −1 , indicating that DNA was extracted from roughly the same amount of biomass.…”

The cyanobacterium Mastigocladus fulfills the nitrogen demand of a terrestrial hot spring microbial mat

“…Although thermal systems around the world have attracted considerable interest and their overall biology and organisms have been characterized (Stewart, 1970;Miller et al, 2006;Steunou et al, 2008;Hamilton et al, 2011;Loiacono et al, 2012;Huang et al, 2013), our knowledge on the identity and relevance of diazotrophs in such systems has Figure 4 Nitrogen fixation assessed by the ARA and 15 N 2 uptake analysis for the different temperatures and years investigated. ARA measurements (black bars) were conducted during the 4 years, whereas 15 N 2 uptake measurements (gray bars) were performed in 2012 and 2013.…”

“…They are typically dominated by a range of microorganisms that form well-defined 'mats' that are constantly being over run by hot spring water. A variety of physical and chemical features, such as the pH (Hamilton et al, 2011;Loiacono et al, 2012;Huang et al, 2013), sulfide concentration (Purcell et al, 2007) and temperature (Miller et al, 2009;Wang et al, 2013) shape the microbial presence and life cycle in these ecosystems. Temperature is considered the most important variable associated with changes and metabolic adaptations in microbial mat communities in hot springs with a neutral pH (Cole et al, 2013;Mackenzie et al, 2013).…”

Microbial community analysis of a full-scale DEMON bioreactor

“…Among these, one of the most powerful is the high-throughput sequencing process. This PCR-based next-level sequencing technique has been successfully applied for the analysis of microbial community structure of many ecosystems such as aquifers, arctic seas, greywater biofilters, hot springs or partial nitritation biofilters [7][8][9][10][11]. Also, identification of microbial populations of autotrophic nitrogen removal bioreactors through nextgeneration sequencing has been achieved.…”