Dataset Information

Autochthonous eukaryotic diversity in hydrothermal sediment and experimental microcolonizers at the Mid-Atlantic Ridge.

ABSTRACT: The diversity and mode of life of microbial eukaryotes in hydrothermal systems is very poorly known. We carried out a molecular survey based on 18S ribosomal RNA genes of eukaryotes present in different hydrothermal niches at the Mid-Atlantic Ridge. These included metal-rich and rare-earth-element-rich hydrothermal sediments of the Rainbow site, fluid-seawater mixing regions, and colonization devices (microcolonizers) containing organic, iron-rich, and porous mineral substrates that were exposed for 15 days to a fluid source. We identified considerable phylogenetic diversity, both at kingdom level and within kinetoplastids and alveolates. None of our sequences affiliates to photosynthesizing lineages, suggesting that we are targeting only autochthonous deep-sea communities. Although sediment harbored most phylogenetic diversity, microcolonizers predominantly contained bodonids and ciliates, indicating that these protists pioneer the colonization process. Given the large variety of divergent lineages detected within the alveolates in deep-sea plankton, hydrothermal sediments, and vents, alveolates seem to dominate the deep ocean in terms of diversity. Compared with data from the Pacific Guaymas basin, some protist lineages seem ubiquitous in hydrothermal areas, whereas others, notably kinetoplastid lineages, very abundant and diverse in our samples, so far have been detected only in Atlantic systems. Unexpectedly, although alvinellid polychaetes are considered endemic of Pacific vents, we detected alvinellid-related sequences at the fluid-seawater interface and in microcolonizers. This finding can boost further studies on deep-sea vent animal biology and biogeography.

SUBMITTER: Lopez-Garcia P

PROVIDER: S-EPMC141059 | biostudies-literature | 2003 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Autochthonous eukaryotic diversity in hydrothermal sediment and experimental microcolonizers at the Mid-Atlantic Ridge.

López-García Purificación P Philippe Hervé H Gail Françoise F Moreira David D

Proceedings of the National Academy of Sciences of the United States of America 20030109 2

The diversity and mode of life of microbial eukaryotes in hydrothermal systems is very poorly known. We carried out a molecular survey based on 18S ribosomal RNA genes of eukaryotes present in different hydrothermal niches at the Mid-Atlantic Ridge. These included metal-rich and rare-earth-element-rich hydrothermal sediments of the Rainbow site, fluid-seawater mixing regions, and colonization devices (microcolonizers) containing organic, iron-rich, and porous mineral substrates that were exposed ...[more]

PMID: 12522264

Similar Datasets

Project description:The slow-spreading Mid-Atlantic Ridge (MAR) forms geological heterogeneity throughout the ridge system by deep crustal faults and their resultant tectonic valleys, which results in the existence of different types of hydrothermal vent fields. Therefore, investigating MAR hydrothermal systems opens a gate to understanding the concentration ranges of ecosystem-limiting metals emanating from compositionally distinct fluids for both near-field chemosynthetic ecosystems and far-field transport into the ocean interiors. Here, we present novel data regarding onboard measured, size-fractionated soluble, colloidal, and particulate iron concentrations from the 2018 R/V L'Atalante - ROV Victor research expedition, during which samples were taken from the mixing zone of black smokers using a ROV-assisted plume sampling. Iron size fractionation (<20, 20-200, and >200nm) data were obtained from onboard sequential filtering, followed by measurement via ferrozine assay and spectrophotometric detection at 562nm. Our results showed the persistent presence of a nanoparticulate/colloidal phase (retained within 20-200nm filtrates) even in high-temperature samples. A significant fraction of this phase was retrievable only under treatment with HNO3 - a strong acid known to attack and dissolve pyrite nanocrystals. Upon mixing with colder bottom waters and removal of iron in the higher parts of the buoyant plume, the larger size fractions became dominant as the total iron levels decreased, but it was still possible to detect significant (micromolar) levels of nanoparticulate Fe even in samples collected 5m above the orifice in the rising plume. The coolest sample (<10°C) still contained more than 1μM of only nitric acid-leachable nanoparticle/colloidal, at least 200 times higher than a typical Fe concentration in the non-buoyant plume. Our results support previous reports of dissolved Fe in MAR vent plumes, and we propose that this recalcitrant Fe pool - surviving immediate precipitation - contributes to maintaining high hydrothermal iron fluxes to the deep ocean.

Project description:The phylogenetic diversity was determined for a microbial community obtained from an in situ growth chamber placed on a deep-sea hydrothermal vent on the Mid-Atlantic Ridge (23 degrees 22' N, 44 degrees 57' W). The chamber was deployed for 5 days, and the temperature within the chamber gradually decreased from 70 to 20 degrees C. Upon retrieval of the chamber, the DNA was extracted and the small-subunit rRNA genes (16S rDNA) were amplified by PCR using primers specific for the Archaea or Bacteria domain and cloned. Unique rDNA sequences were identified by restriction fragment length polymorphisms, and 38 different archaeal and bacterial phylotypes were identified from the 85 clones screened. The majority of the archaeal sequences were affiliated with the Thermococcales (71%) and Archaeoglobales (22%) orders. A sequence belonging to the Thermoplasmales confirms that thermoacidophiles may have escaped enrichment culturing attempts of deep-sea hydrothermal vent samples. Additional sequences that represented deeply rooted lineages in the low-temperature eurarchaeal (marine group II) and crenarchaeal clades were obtained. The majority of the bacterial sequences obtained were restricted to the Aquificales (18%), the epsilon subclass of the Proteobacteria (epsilon-Proteobacteria) (40%), and the genus Desulfurobacterium (25%). Most of the clones (28%) were confined to a monophyletic clade within the epsilon-Proteobacteria with no known close relatives. The prevalence of clones related to thermophilic microbes that use hydrogen as an electron donor and sulfur compounds (S(0), SO(4), thiosulfate) indicates the importance of hydrogen oxidation and sulfur metabolism at deep-sea hydrothermal vents. The presence of sequences that are related to sequences from hyperthermophiles, moderate thermophiles, and mesophiles suggests that the diversity obtained from this analysis may reflect the microbial succession that occurred in response to the shift in temperature and possible associated changes in the chemistry of the hydrothermal fluid.

Project description:In this study, sediments were collected from two different sites in the deep-sea hydrothermal region of the South Atlantic Ocean. Two microbial enrichment cultures (H7S and H11S), which were enriched from the sediments collected at two sample sites, could effectively degrade petroleum hydrocarbons. The bacterial diversity was analyzed by high-throughput sequencing method. The petroleum degradation ability were evaluated by gas chromatography-mass spectrometry and gravimetric analysis. We found that the dominant oil-degrading bacteria of enrichment cultures from the deep-sea hydrothermal area belonged to the genera Pseudomonas, Nitratireductor, Acinetobacter, and Brevundimonas. After a 14-day degradation experiment, the enrichment culture H11S, which was obtained near a hydrothermal vent, exhibited a higher degradation efficiency for alkanes (95%) and polycyclic aromatic hydrocarbons (88%) than the enrichment culture H7S. Interestingly, pristane and phytane as biomarkers were degraded up to 90% and 91% respectively by the enrichment culture H11S, and six culturable oil-degrading bacterial strains were isolated. Acinetobacter junii strain H11S-25, Nitratireductor sp. strain H11S-31 and Pseudomonas sp. strain H11S-28 were used at a density ratio of 95:4:1 to construct high-efficiency oil-degrading consortium H. After a three-day biodegradation experiment, consortium H showed high degradation efficiencies of 74.2% and 65.7% for total alkanes and PAHs, respectively. The degradation efficiency of biomarkers such as pristane and high-molecular-weight polycyclic aromatic hydrocarbons (such as CHR) reached 84.5% and 80.48%, respectively. The findings of this study indicate that the microorganisms in the deep-sea hydrothermal area are potential resources for degrading petroleum hydrocarbons. Consortium H, which was artificially constructed, showed a highly efficient oil-degrading capacity and has significant application prospects in oil pollution bioremediation.

Project description:BackgroundDeep-sea hydrothermal vents represent unique ecosystems that redefine our understanding of the limits of life. They are widely distributed in deep oceans and typically form along mid-ocean ridges. To date, the hydrothermal systems in the Mid-Atlantic Ridge south of 14°S remain barely explored, limiting our understanding of the microbial community in this distinct ecosystem. The Deyin-1 is a newly discovered hydrothermal field in this area. By applying the metagenomic analysis, we aim at gaining much knowledge of the biodiversity and functional capability of microbial community inhabiting this field.ResultsIn the current study, 219 metagenomic assembled genomes (MAGs) were reconstructed, unveiling a diverse and variable community dominated by Bacteroidetes, Nitrospirae, Alpha-, Delta-, and Gammaproteobacteria in the active and inactive chimney samples as well as hydrothermal oxide samples. Most of these major taxa were potentially capable of using reduced sulfur and hydrogen as primary energy sources. Many members within the major taxa exhibited potentials of metabolic plasticity by possessing multiple energy metabolic pathways. Among these samples, different bacteria were found to be the major players of the same metabolic pathways, further supporting the variable and functionally redundant community in situ. In addition, a high proportion of MAGs harbored the genes of carbon fixation and extracellular carbohydrate-active enzymes, suggesting that both heterotrophic and autotrophic strategies could be essential for their survival. Notably, for the first time, the genus Candidatus Magnetobacterium was shown to potentially fix nitrogen, indicating its important role in the nitrogen cycle of inactive chimneys. Moreover, the metabolic plasticity of microbes, diverse and variable community composition, and functional redundancy of microbial communities may represent the adaptation strategies to the geochemically complex and fluctuating environmental conditions in deep-sea hydrothermal fields.ConclusionsThis represents the first assembled-genome-based investigation into the microbial community and metabolism of a hydrothermal field in the Mid-Atlantic Ridge south of 14°S. The findings revealed that a high proportion of microbes could benefit from simultaneous use of heterotrophic and autotrophic strategies in situ. It also presented novel members of potential diazotrophs and highlighted the metabolic plasticity and functional redundancy across deep-sea hydrothermal systems. Video abstract.

Dataset Information

Autochthonous eukaryotic diversity in hydrothermal sediment and experimental microcolonizers at the Mid-Atlantic Ridge.

Publications

Autochthonous eukaryotic diversity in hydrothermal sediment and experimental microcolonizers at the Mid-Atlantic Ridge.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets