Affiliation:
1. Department of Land Resources and Environmental Sciences
2. Thermal Biology Institute, Montana State University, Bozeman, Montana 59717
Abstract
ABSTRACT
In this paper we describe the bacterial communities associated with natural hydrocarbon seeps in nonthermal soils at Rainbow Springs, Yellowstone National Park. Soil chemical analysis revealed high sulfate concentrations and low pH values (pH 2.8 to 3.8), which are characteristic of acid-sulfate geothermal activity. The hydrocarbon composition of the seep soils consisted almost entirely of saturated, acyclic alkanes (e.g.,
n-
alkanes with chain lengths of C
15
to C
30
, as well as branched alkanes, predominately pristane and phytane). Bacterial populations present in the seep soils were phylogenetically characterized by 16S rRNA gene clone library analysis. The majority of the sequences recovered (>75%) were related to sequences of heterotrophic acidophilic bacteria, including
Acidisphaera
spp. and
Acidiphilium
spp. of the α-
Proteobacteria
. Clones related to the iron- and sulfur-oxidizing chemolithotroph
Acidithiobacillus
spp. were also recovered from one of the seep soils. Hydrocarbon-amended soil-sand mixtures were established to examine [
14
C]hexadecane mineralization and corresponding changes in the bacterial populations using denaturing gradient gel electrophoresis (DGGE) of 16S rRNA gene fragments. Approximately 50% of the [
14
C]hexadecane added was recovered as
14
CO
2
during an 80-day incubation, and this was accompanied by detection of heterotrophic acidophile-related sequences as dominant DGGE bands. An alkane-degrading isolate was cultivated, whose 16S rRNA gene sequence was identical to the sequence of a dominant DGGE band in the soil-sand mixture, as well as the clone sequence recovered most frequently from the original soil. This and the presence of an
alkB
gene homolog in this isolate confirmed the alkane degradation capability of one population indigenous to acidic hydrocarbon seep soils.
Publisher
American Society for Microbiology
Subject
Ecology,Applied Microbiology and Biotechnology,Food Science,Biotechnology
Cited by
71 articles.
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