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Metabolically active eukaryotic communities in extremely acidic mine drainage.
Brett J Baker1, Michelle A Lutz, Scott C Dawson
1Department of Earth and Planetary Sciences, 40 Hilgard Hall, University of California at Berkeley, Berkeley, CA 94720, USA. bbaker@eps.berkeley.edu.
Applied and Environmental Microbiology
|October 7, 2004
Summary
Microbial eukaryotes, including fungi and protists, play a key role in acid mine drainage (AMD) biofilms. This study identified new fungal species, Acidomyces richmondensis, and revealed Eurotiomycetes are more abundant in AMD environments.
Area of Science:
- Microbiology
- Environmental Science
- Eukaryotic Ecology
Background:
- Acid mine drainage (AMD) ecosystems are characterized by extreme acidity, high metal concentrations, and elevated temperatures.
- Microbial eukaryotes, such as fungi and protists, significantly influence AMD microbial community structure and function, impacting prokaryotic populations and biogeochemical processes.
- Understanding eukaryotic diversity is crucial for comprehending AMD generation rates, as prokaryotes regulate iron oxidation.
Purpose of the Study:
- To characterize the diversity and distribution of microbial eukaryotes in AMD environments.
- To identify and name novel fungal species inhabiting these extreme conditions.
- To investigate the relative abundance of different fungal lineages using molecular and in situ techniques.
Main Methods:
- Phylogenetic analysis of 18S rRNA and beta-tubulin genes for eukaryotic identification.
- Isolation and culturing of fungal species from AMD samples.
- Fluorescent in situ hybridization (FISH) using rRNA-specific oligonucleotide probes for in situ detection and quantification.
Main Results:
- Identification of a Rhodophyta (red algae) lineage and Vahlkampfiidae protists.
- Fungal sequences clustered into two distinct groups, Dothideomycetes and Eurotiomycetes.
- Three fungal isolates were obtained and named Acidomyces richmondensis, closely related to Dothideomycetes.
- FISH analysis revealed Eurotiomycetes were consistently more abundant than Dothideomycetes across seven sampling locations.
- This study represents the first integration of culture-independent fungal detection with in situ detection and activity assessment in acidic environments.
Conclusions:
- The study expands the understanding of eukaryotic community structure within AMD subsurface environments.
- Novel fungal lineages, including Acidomyces richmondensis, were identified and characterized.
- Quantitative in situ data demonstrate differential abundance of fungal classes (Eurotiomycetes > Dothideomycetes) in AMD biofilms.
- Eukaryotic microbes are integral components of AMD ecosystems, influencing overall community dynamics and geochemistry.