Microbial communities and their predicted metabolic characteristics in deep fracture groundwaters of the crystalline bedrock at Olkiluoto, Finland
The microbial diversity in oligotrophic isolated crystalline Fennoscandian Shield bedrock fracture groundwaters is high, but the core community has not been identified. Here we characterized the bacterial and archaeal communities in 12 water conductive fractures situated at depths between 296 and 79...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-11-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/13/6031/2016/bg-13-6031-2016.pdf |
| Summary: | The microbial diversity in oligotrophic isolated crystalline Fennoscandian
Shield bedrock fracture groundwaters is high, but the core community has not
been identified. Here we characterized the bacterial and archaeal communities
in 12 water conductive fractures situated at depths between 296 and 798 m by
high throughput amplicon sequencing using the Illumina HiSeq platform.
Between 1.7 × 10<sup>4</sup> and 1.2 × 10<sup>6</sup> bacterial or
archaeal sequence reads per sample were obtained. These sequences revealed
that up to 95 and 99 % of the bacterial and archaeal sequences obtained
from the 12 samples, respectively, belonged to only a few common species,
i.e. the core microbiome. However, the remaining rare microbiome contained
over 3- and 6-fold more bacterial and archaeal taxa. The metabolic properties
of the microbial communities were predicted using PICRUSt. The approximate
estimation showed that the metabolic pathways commonly included fermentation,
fatty acid oxidation, glycolysis/gluconeogenesis, oxidative phosphorylation,
and methanogenesis/anaerobic methane oxidation, but carbon fixation through
the Calvin cycle, reductive TCA cycle, and the Wood–Ljungdahl pathway was
also predicted. The rare microbiome is an unlimited source of genomic
functionality in all ecosystems. It may consist of remnants of microbial
communities prevailing in earlier environmental conditions, but could also be
induced again if changes in their living conditions occur. |
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| ISSN: | 1726-4170 1726-4189 |