Abstract
The diversity and functional role of fungi, one of the
ecologically most important groups of eukaryotic
microorganisms, remains largely unknown in deep biosphere
environments. In this study we investigated fungal
communities in packer-isolated bedrock fractures in
Olkiluoto, Finland at depths ranging from 296 to 798 m
below surface level. DNA- and cDNA-based high-throughput
amplicon sequencing analysis of the fungal internal
transcribed spacer (ITS) gene markers was used to examine
the total fungal diversity and to identify the active
members in deep fracture zones at different depths.
Results showed that fungi were present in fracture zones
at all depths and fungal diversity was higher than
expected. Most of the observed fungal sequences belonged
to the phylum Ascomycota. Phyla Basidiomycota and
Chytridiomycota were only represented as a minor part of
the fungal community. Dominating fungal classes in the
deep bedrock aquifers were Sordariomycetes,
Eurotiomycetes, and Dothideomycetes from the Ascomycota
phylum and classes Microbotryomycetes and Tremellomycetes
from the Basidiomycota phylum, which are the most
frequently detected fungal taxa reported also from deep
sea environments. In addition some fungal sequences
represented potentially novel fungal species. Active
fungi were detected in most of the fracture zones, which
proves that fungi are able to maintain cellular activity
in these oligotrophic conditions. Possible roles of fungi
and their origin in deep bedrock groundwater can only be
speculated in the light of current knowledge but some
species may be specifically adapted to deep subsurface
environment and may play important roles in the
utilization and recycling of nutrients and thus
sustaining the deep subsurface microbial community.
Original language | English |
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Article number | 573 |
Journal | Frontiers in Microbiology |
Volume | 6 |
DOIs | |
Publication status | Published - 2015 |
MoE publication type | A1 Journal article-refereed |
Keywords
- fungal communities
- high-throughput sequencing
- crystalline bedrock fracture
- Fennoscandian shield
- deep biosphere