Evidence for hydrothermal Archaea within the basaltic flanks of the East Pacific Rise

Ehrhardt, Christopher J.; Haymon, Rachel M.; LaMontagne, Michael G.; Holden, Patricia A.

doi:10.1111/j.1462-2920.2006.01211.x

Cited by 40 publications

(25 citation statements)

References 45 publications

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“…Such hyperthermophilic archaeal phylotypes were also detected in the APcsc sample associated with low temperature fluids (19°C). The presence of phylotypes related to hyperthermophilic archaea in low temperature environments (Ͻ12°C) has also been reported by other researchers (16,35).…”

Section: Resultsmentioning

confidence: 59%

Biogeography and Biodiversity in Sulfide Structures of Active and Inactive Vents at Deep-Sea Hydrothermal Fields of the Southern Mariana Trough

Kato

Takano

Kakegawa

et al. 2010

Appl Environ Microbiol

136

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The abundance, diversity, activity, and composition of microbial communities in sulfide structures both of active and inactive vents were investigated by culture-independent methods. These sulfide structures were collected at four hydrothermal fields, both on-and off-axis of the back-arc spreading center of the Southern Mariana Trough. The microbial abundance and activity in the samples were determined by analyzing total organic content, enzymatic activity, and copy number of the 16S rRNA gene. To assess the diversity and composition of the microbial communities, 16S rRNA gene clone libraries including bacterial and archaeal phylotypes were constructed from the sulfide structures. Despite the differences in the geological settings among the sampling points, phylotypes related to the Epsilonproteobacteria and cultured hyperthermophilic archaea were abundant in the libraries from the samples of active vents. In contrast, the relative abundance of these phylotypes was extremely low in the libraries from the samples of inactive vents. These results suggest that the composition of microbial communities within sulfide structures dramatically changes depending on the degree of hydrothermal activity, which was supported by statistical analyses. Comparative analyses suggest that the abundance, activity and diversity of microbial communities within sulfide structures of inactive vents are likely to be comparable to or higher than those in active vent structures, even though the microbial community composition is different between these two types of vents. The microbial community compositions in the sulfide structures of inactive vents were similar to those in seafloor basaltic rocks rather than those in marine sediments or the sulfide structures of active vents, suggesting that the microbial community compositions on the seafloor may be constrained by the available energy sources. Our findings provide helpful information for understanding the biogeography, biodiversity and microbial ecosystems in marine environments.

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Section: Resultsmentioning

confidence: 59%

Biogeography and Biodiversity in Sulfide Structures of Active and Inactive Vents at Deep-Sea Hydrothermal Fields of the Southern Mariana Trough

Kato

Takano

Kakegawa

et al. 2010

Appl Environ Microbiol

136

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“…As only one archaeal 16S rRNA phylotype (by using a threshold of 97% sequence similarity) was found in the enrichment, the retrieved archaeal amoA and amoB gene fragments most likely also originated from this phylotype. In contrast to previous studies, which only reported the presence of AOA-related 16S rRNA or crenarchaeotal amoA gene fragments in thermophilic environments (19,20,(31)(32)(33), we specifically identified the respective organism by CARD-FISH with 16S rRNA-targeted probes as cocci in irregularly shaped aggregates. Furthermore, we propose three independent lines of evidence that, taken together, strongly suggest that the detected archaeon is actually an AOA.…”

Section: Discussionmentioning

confidence: 56%

A moderately thermophilic ammonia-oxidizing crenarchaeote from a hot spring

Hatzenpichler¹,

Лебедева

Spieck

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

630

541

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The recent discovery of ammonia-oxidizing archaea (AOA) dramatically changed our perception of the diversity and evolutionary history of microbes involved in nitrification. In this study, a moderately thermophilic (46°C) ammonia-oxidizing enrichment culture, which had been seeded with biomass from a hot spring, was screened for ammonia oxidizers. Although gene sequences for crenarchaeotal 16S rRNA and two subunits of the ammonia monooxygenase (amoA and amoB) were detected via PCR, no hints for known ammonia-oxidizing bacteria were obtained. Comparative sequence analyses of these gene fragments demonstrated the presence of a single operational taxonomic unit and thus enabled the assignment of the amoA and amoB sequences to the respective 16S rRNA phylotype, which belongs to the widely distributed group I.1b (soil group) of the Crenarchaeota. Catalyzed reporter deposition (CARD)-FISH combined with microautoradiography (MAR) demonstrated metabolic activity of this archaeon in the presence of ammonium. This finding was corroborated by the detection of amoA gene transcripts in the enrichment. CARD-FISH/ MAR showed that the moderately thermophilic AOA is highly active at 0.14 and 0.79 mM ammonium and is partially inhibited by a concentration of 3.08 mM. The enriched AOA, which is provisionally classified as ''Candidatus Nitrososphaera gargensis,'' is the first described thermophilic ammonia oxidizer and the first member of the crenarchaeotal group I.1b for which ammonium oxidation has been verified on a cellular level. Its preference for thermophilic conditions reinvigorates the debate on the thermophilic ancestry of AOA.ammonia oxidation ͉ archaea ͉ nitrification ͉ thermophile ͉ amoA N itrification, the successive microbial oxidation of ammonia via nitrite to nitrate, is a crucial step in the biogeochemical nitrogen cycle, and ammonia-oxidizing microorganisms catalyze the first, rate-limiting step of this process. Until recently, the microbiology of ammonia oxidation was thought to be well understood. Aerobic, chemolithoautotrophic bacteria within the Beta-and Gammaproteobacteria were the only known ammoniaoxidizing microorganisms (1, 2). However, in the last few years, this understanding has been radically changed, first, by the discovery that ammonium can also be oxidized anaerobically by a clade of deep branching planctomycetes (3, 4), and later by the equally surprising cultivation of ammonia-oxidizing archaea (AOA) belonging to the Crenarchaeota (5). Since then, AOA were found to outnumber ammonia-oxidizing bacteria (AOB) in several terrestrial and marine systems, including different soils (6), the North Sea and Atlantic Ocean (7), the Pacific Ocean (8), and the Black Sea (9). Furthermore, molecular analyses demonstrated that AOA also occur in association with marine sponges (10-13), and amoA sequences related to recognized AOA were retrieved in numerous studies from a wide variety of other habitats (7-9, 14-18), including two moderately thermophilic sites with a temperature below 50°C (19,20). The latter findin...

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“…One possibility would be the existence of a chemolitotrophic community within the basalt (Edwards et al, 2005;Stevens, 1997). Such communities were previously described for the flanks of the mid-ocean ridges (Ehrhardt et al, 2007;Huber et al, 2006) but their existence under the ocean basins remains controversial (Cowen et al, 2003). Drilling into the basalt under the SPG is necessary to further address this issue.…”

Section: Basement Fluxesmentioning

confidence: 98%

Oxygen penetration deep into the sediment of the South Pacific gyre

et al. 2009

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Abstract. Sediment oxygen concentration profiles and benthic microbial oxygen consumption rates were investigated during an IODP site survey in the South Pacific Gyre. Primary production, particle fluxes and sedimentation rates are extremely low in this ultra-oligotrophic oceanic region. We derived O 2 consumption rates from vertical oxygen profiles in sediments obtained on different spatial scales ex situ (in piston cores and multi cores), and in situ (using a benthic lander equipped with a microelectrode profiler). Along a transect in the area 24 to 46 • S and 165 to 117 • W, cores from 10 out of 11 sites were oxygenated over their entire length (as much as 8 m below seafloor), with deep O 2 concentrations >150 µmol L −1 . This represents the deepest oxygen penetration ever measured in marine sediments. High-resolution microprofiles from the surface sediment layer revealed a diffusive oxygen uptake between 0.1 and 1.3 mmol m −2 d −1 , equal to a carbon mineralization rate of ∼0.4-4.5 gC m −2 yr −1 . This is in the lower range of previously reported fluxes for oligotrophic sediments but corresponds well to the low surface water primary production. Half of the pool of reactive organic matter was consumed in the top 1.5-6 mm of the sediment. Because of the inert nature of the deeper sediment, oxygen that is not consumed within the top centimeters diffuses downward to much greater depth. In deeper zones, a small O 2 flux between 0.05 and 0.3 µmol m −2 d −1 was still present. This flux was nearly constant with depth, indicating extremely low O 2 consumption rates. Modeling of the oxygen profiles suggests that the sediment is probably oxygenated down to the basalt, suggesting an oxygen flux from the sediment into the basaltic basement.

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Evidence for hydrothermal Archaea within the basaltic flanks of the East Pacific Rise

Cited by 40 publications

References 45 publications

Biogeography and Biodiversity in Sulfide Structures of Active and Inactive Vents at Deep-Sea Hydrothermal Fields of the Southern Mariana Trough

Biogeography and Biodiversity in Sulfide Structures of Active and Inactive Vents at Deep-Sea Hydrothermal Fields of the Southern Mariana Trough

A moderately thermophilic ammonia-oxidizing crenarchaeote from a hot spring

Oxygen penetration deep into the sediment of the South Pacific gyre

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