Microbial Communities in a Shallow-Sea Hydrothermal System

ABSTRACT Microbial communities in a shallow submarine hydrothermal system near Taketomi Island, Japan, were investigated using cultivation-based and molecular techniques. The main hydrothermal activity occurred in a craterlike basin (depth, ∼23 m) on the coral reef seafloor. The vent fluid (maximum temperature, >52°C) contained 175 μM H2S and gas bubbles mainly composed of CH4 (69%) and N2 (29%). A liquid serial dilution cultivation technique targeting a variety of metabolism types quantified each population in the vent fluid and in a white microbial mat located near the vent. The most abundant microorganisms cultivated from both the fluid and the mat were autotrophic sulfur oxidizers, including mesophilic Thiomicrospira spp. and thermophilic Sulfurivirga caldicuralii. Methane oxidizers were the second most abundant organisms in the fluid; one novel type I methanotroph exhibited optimum growth at 37°C, and another novel type I methanotroph exhibited optimum growth at 45°C. The number of hydrogen oxidizers cultivated only from the mat was less than the number of sulfur and methane oxidizers, although a novel mesophilic hydrogen-oxidizing member of the Epsilonproteobacteria was isolated. Various mesophilic to hyperthermophilic heterotrophs, including sulfate-reducing Desulfovibrio spp., iron-reducing Deferribacter sp., and sulfur-reducing Thermococcus spp., were also cultivated. Culture-independent 16S rRNA gene clone analysis of the vent fluid and mat revealed highly diverse archaeal communities. In the bacterial community, S. caldicuralii was identified as the predominant phylotype in the fluid (clonal frequency, 25%). Both bacterial clone libraries indicated that there were bacterial communities involved in sulfur, hydrogen, and methane oxidation and sulfate reduction. Our results indicate that there are unique microbial communities that are sustained by active chemosynthetic primary production rather than by photosynthetic production in a shallow hydrothermal system where sunlight is abundant.

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Energy sources for chemolithotrophs in an arsenic- and iron-rich shallow-sea hydrothermal system

Geobiology ◽

10.1111/j.1472-4669.2011.00291.x ◽

2011 ◽

Vol 9 (5) ◽

pp. 436-445 ◽

Cited By ~ 23

Author(s):

N. H. AKERMAN ◽

R. E. PRICE ◽

T. PICHLER ◽

J. P. AMEND

Keyword(s):

Hydrothermal System ◽

Energy Sources ◽

Shallow Sea

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Yeosuana marina sp. nov., isolated from shallow-sea hydrothermal systems off Kueishantao Island

INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY ◽

10.1099/ijsem.0.004525 ◽

2020 ◽

Vol 70 (12) ◽

pp. 6251-6256 ◽

Cited By ~ 3

Author(s):

Qingfeng Zhang ◽

Dan Lin ◽

Jianing Ye ◽

Ta-Hui Lin ◽

Chenlan Li ◽

...

Keyword(s):

16S Rrna ◽

16S Rrna Gene ◽

Hydrothermal System ◽

Type Species ◽

Rrna Gene ◽

Shallow Sea ◽

Gene Sequences ◽

16S Rrna Gene Sequences ◽

Content Type ◽

Link Type

A novel Gram-stain-negative, non-flagellated, non-motile, rod-shaped (0.4–0.6×1.8–2.5 µm), aerobic bacterial strain, designated JLT21T, was isolated from seawater of a shallow-sea hydrothermal system. Growth occurred with 0–4.0 % (w/v) NaCl (optimum, 2.0 % NaCl), at 8–45 °C (optimum, 25 °C) and at pH 3.0–10.0 (optimum, pH 7.0). Analysis of 16S rRNA gene sequences revealed that strain JLT21T showed the highest 16S rRNA gene sequence similarity to Gaetbulibacter aquiaggeris KEM-8T (97.2 %), Gaetbulibacter marinus IMCC1914T (96.9 %) and Yeosuana aromativorans GW1-1T (96.9 %). Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain JLT21T clustered with Y. aromativorans GW1-1T. The predominant respiratory quinone of strain JLT21T was menaquinone-6 (MK-6). Polar lipids were phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, three unidentified glycolipids and four unidentified lipids. The major fatty acids of strain JLT21T were iso-C15 : 0 (21.7 %), C16 : 1 ω6c/ω7c (11.5 %) and iso-C17 : 0 3-OH (10.9 %). The DNA G+C content of strain JLT21T was 32.6 %. On the basis of polyphasic analysis, strain JLT21T is considered to represent a novel species of the genus Yeosuana , for which the name Yeosuana marina sp. nov. is proposed. The type strain of Yeosuana marina is JLT21T (=CGMCC 1.15787T=JCM 31511T). The study helps us better understand the bacterial species in the shallow-sea hydrothermal system and their adaptations to the hydrothermal environment.

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