Inter-field variability in the microbial communities of hydrothermal vent deposits from a back-arc basin

ArticleinGeobiology 10(4):333-46 · March 2012with28 Reads
DOI: 10.1111/j.1472-4669.2012.00325.x · Source: PubMed
Abstract
Diverse microbial communities thrive on and in deep-sea hydrothermal vent mineral deposits. However, our understanding of the inter-field variability in these communities is poor, as limited sampling and sequencing efforts have hampered most previous studies. To explore the inter-field variability in these communities, we used barcoded pyrosequencing of the variable region 4 (V4) of the 16S rRNA gene to characterize the archaeal and bacterial communities of over 30 hydrothermal deposit samples from six vent fields located along the Eastern Lau Spreading Center. Overall, the bacterial and archaeal communities of the Eastern Lau Spreading Center are similar to other active vent deposits, with a high diversity of Epsilonproteobacteria and thermophilic Archaea. However, the archaeal and bacterial communities from the southernmost vent field, Mariner, were significantly different from the other vent fields. At Mariner, the epsilonproteobacterial genus Nautilia and the archaeal family Thermococcaceae were prevalent in most samples, while Lebetimonas and Thermofilaceae were more abundant at the other vent fields. These differences appear to be influenced in part by the unique geochemistry of the Mariner fluids resulting from active degassing of a subsurface magma chamber. These results show that microbial communities associated with hydrothermal vent deposits in back-arc basins are taxonomically similar to those from mid-ocean ridge systems, but differences in geologic processes between vent fields in a back-arc basin can influence microbial community structure.
    • "Advances in culturing approaches (e.g., for review, Stetter 1999 among others) have resulted in many new descriptions, continuing to challenge our understanding of extremophiles and biological processes never previously detected at deep-sea vents (e.g., Reysenbach et al. 2000Reysenbach et al. , 2006 Slobodkin et al. 2013). High-throughput sequencing technologies and metagenomics have revealed differences in the microbial communities within and between vent fields on a global scale which appear to be driven in part by differences in vent fluid composition, including pH (Flores et al. , 2012). Anna-Louise Reysenbach's oral contribution to the symposium discussed how metagenomics could be utilized to investigate metabolic pathways used by archaeal and bacterial extremophiles and to look for indicators as to how the physical environment impacts community assembly from a genomic perspective. "
    [Show abstract] [Hide abstract] ABSTRACT: Life persists, even under extremely harsh conditions. While the existence of extremophiles is well known, the mechanisms by which these organisms evolve, perform basic metabolic functions, reproduce, and survive under extreme physical stress are often entirely unknown. Recent technological advances in terms of both sampling and studying extremophiles have yielded new insight into their evolution, physiology and behavior, from microbes and viruses to plants to eukaryotes. The goal of the "Life on the Edge-the Biology of Organisms Inhabiting Extreme Environments" symposium was to unite researchers from taxonomically and methodologically diverse backgrounds to highlight new advances in extremophile biology. Common themes and new insight that emerged from the symposium included the important role of symbiotic associations, the continued challenges associated with sampling and studying extremophiles and the important role these organisms play in terms of studying climate change. As we continue to explore our planet, especially in difficult to reach areas from the poles to the deep sea, we expect to continue to discover new and extreme circumstances under which life can persist.
    Full-text · Article · Jul 2016
    • "The reduced statistical power may have also reduced our ability to discern differences between and among hydrothermal systems (e.g., shallow vs. deep vents where we expected to observe greater differences due to the differences in temperature, pressure, light and geochemistry). Some recent studies have utilized a greater sampling effort to examine variability in deep-sea vent communities and found both intraand inter-field variability in communities potentially driven by large scale differences in geological and geochemical processes, while in other comparisons, communities were indistinguishable (Flores et al., 2011Flores et al., , 2012). Ongoing work in the WP vent system will address this issue of biogeographic variation (Roussos et al., unpublished). "
    [Show abstract] [Hide abstract] ABSTRACT: The shallow-sea hydrothermal vents at White Point (WP) in Palos Verdes on the southern California coast support microbial mats and provide easily accessed settings in which to study chemolithoautotrophic sulfur cycling. Previous studies have cultured sulfur-oxidizing bacteria from the WP mats; however, almost nothing is known about the in situ diversity and activity of the microorganisms in these habitats. We studied the diversity, micron-scale spatial associations and metabolic activity of the mat community via sequence analysis of 16S rRNA and aprA genes, fluorescence in situ hybridization (FISH) microscopy and sulfate reduction rate (SRR) measurements. Sequence analysis revealed a diverse group of bacteria, dominated by sulfur cycling gamma-, epsilon-, and deltaproteobacterial lineages such as Marithrix, Sulfurovum, and Desulfuromusa. FISH microscopy suggests a close physical association between sulfur-oxidizing and sulfur-reducing genotypes, while radiotracer studies showed low, but detectable, SRR. Comparative 16S rRNA gene sequence analyses indicate the WP sulfur vent microbial mat community is similar, but distinct from other hydrothermal vent communities representing a range of biotopes and lithologic settings. These findings suggest a complete biological sulfur cycle is operating in the WP mat ecosystem mediated by diverse bacterial lineages, with some similarity with deep-sea hydrothermal vent communities.
    Full-text · Article · Jul 2016
    • "Small-subunit ribosomal RNA (SSU rRNA) genes were used as marker genes to reconstruct the community structure of bacteria, archaea, and small eukaryotes by high-throughput 454 pyrosequencing [10]. In recent years, this approach has been used successfully to study microbial assemblages in surface oceans [11, 12] and deep-sea HTVs13141516. "
    [Show abstract] [Hide abstract] ABSTRACT: Kueishan Island is a young volcanic island in the southernmost edge of the Okinawa Trough in the northeastern part of Taiwan. A cluster of hydrothermal vents is located off the southeastern tip of the Island at water depths between 10 and 80 m. This paper presents the results of the first study on the microbial communities in bottom sediments collected from the shallow-water hydrothermal vents of Kueishan Island. Small-subunit ribosomal RNA gene-based high-throughput 454 pyrosequencing was used to characterize the assemblages of bacteria, archaea, and small eukaryotes in sediment samples collected at various distances from the hydrothermal vents. Sediment from the vent area contained the highest diversity of archaea and the lowest diversity of bacteria and small eukaryotes. Epsilonproteobacteria were the most abundant group in the vent sediment, but their abundance decreased with increasing distance from the vent area. Most Epsilonproteobacteria belonged to the mesophilic chemolithoautotrophic genera Sulfurovum and Sulfurimonas. Recent reports on these two genera have come from deep-sea hydrothermal vents. Conversely, the relative contribution of Gammaproteobacteria to the bacterial community increased with increasing distance from the vent area. Our study revealed the contrasting effects of venting on the benthic bacterial and archaeal communities, and showed that the sediments of the shallow-waters hydrothermal vents were dominated by chemoautotrophic bacteria. The present work broadens our knowledge on microbial diversity in shallow-water hydrothermal vent habitats. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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