Spatial Distribution of Marine Crenarchaeota Group I in the Vicinity of Deep-Sea Hydrothermal Systems

Abstract

Distribution profiles of marine crenarchaeota group I in the vicinity of deep-sea hydrothermal systems were mapped with culture-independent molecular techniques. Planktonic samples were obtained from the waters surrounding two geographically and geologically distinct hydrothermal systems, and the abundance of marine crenarchaeota group I was examined by 16S ribosomal DNA clone analysis, quantitative PCR, and whole-cell fluorescence in situ hybridization. A much higher proportion of marine crenarchaeota group I within the microbial community was detected in deep-sea hydrothermal environments than in normal deep and surface seawaters. The highest proportion was always obtained from the ambient seawater adjacent to hydrothermal emissions and chimneys but not from the hydrothermal plumes. These profiles were markedly different from the profiles of epsilon-Proteobacteria, which are abundant in the low temperatures of deep-sea hydrothermal environments.The members of marine crenarchaeota group I (MGI) are the most abundant and widely distributed Archaea in the global ocean biosphere from surface to bottom waters and from polar to tropical regions (6-8, 11, 12, 20, 19, 28, 29, 31, 36, 46, 48, 52, 54-56). Since the first discovery of the occurrence of MGI in coastal waters (6, 11), culture-independent molecular surveys have expanded the potential habitats for MGI from marine planktonic fractions to seafloor surfaces (20,55,56), deep subseafloor sediments (16, 17), marine hydrothermal systems (31,46,48), freshwater lakes (26, 39), and deep terrestrial subsurface aquifers (52). Despite their ubiquity in the global aquatic biosphere and the diversity of genes and genomic structures based on rRNA genes (rDNA) and genome fragments obtained directly from environments (3,4,40,44), their physiological features and ecological significance are still unclear due to the lack of success in cultivating them.Recent investigations have begun to provide insights into the metabolic modes and trophic types represented by the MGI. Ouverney and Fuhrman (33), with a technique called substrate tracking autoradiography fluorescence in situ hybridization, demonstrated that members of the MGI were capable of assimilating dissolved amino acids. In contrast, stable carbon isotopic analyses of archaeal membrane lipids (glycerol dibiphytanyl glycerol tetraethers) in the water columns and sediments suggested that most MGI members might be autotrophs, with bicarbonate as a primary carbon source (15,21,22,41,42). Analysis of the archaeal lipids recovered from sediments based on radiocarbon isotopes also supported the nonphototrophic bicarbonate-dependent carbon metabolism of the MGI members (35). Further evidence for autotrophy in MGI was clearly demonstrated by in situ [13 C]bicarbonate tracer experiments (58).In the absence of cultivated organisms, it has been difficult to discern much about the energy metabolism of the MGI members. One might hope that scrutiny of the distribution and abundance of MGI in various environments would provide insights i...

The metatranscriptome of a deep-sea hydrothermal plume is dominated by water column methanotrophs and lithotrophs

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Genome-enabled transcriptomics reveals archaeal populations that drive nitrification in a deep-sea hydrothermal plume

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Indian Ocean Hydrothermal Systems: Seafloor Hydrothermal Activities, Physical and Chemical Characteristics of Hydrothermal Fluids, and Vent-Associated Biological Communities

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“…Based on examination of the relative abundance of Marine Group I (Creanarchaeota and Epsilonproteobacteria) populations in the planktonic microbial communities of the hydrothermal plumes, the communities in the Kairei field showed much less abundant Epsilonproteobacteria populations compared to the Iheya North field of the Okinawa Trough. However, microbial populations other than Marine Group I, such as the SUP05 group Gammaproteobacteria, a cosmopolitan microbial population that dominates hydrothermal plume communities (Sunamura et al 2004;Dick and Tebo 2010), were not quantitatively estimated (Takai et al 2004b). In addition, La Duc et al (et al 2007) reported that many of the heterotrophic bacteria isolated from the Kairei hydrothermal plumes displayed high multi-stressor tolerance to desiccation, peroxide exposure, and UV and gamma ray irradiation.…”