scholarly journals The uptake and excretion of partially oxidized sulfur expands the repertoire of energy resources metabolized by hydrothermal vent symbioses

2015 ◽  
Vol 282 (1806) ◽  
pp. 20142811 ◽  
Author(s):  
R. A. Beinart ◽  
A. Gartman ◽  
J. G. Sanders ◽  
G. W. Luther ◽  
P. R. Girguis
Keyword(s):  
Hydrothermal Vents ◽  
Carbon Fixation ◽  
Sulfide Oxidation ◽  
Sulfur Compounds ◽  
Spreading Center ◽  
Symbiotic Associations ◽  
Flow Through ◽  
Chemoautotrophic Bacteria ◽  
Animal Communities

Symbiotic associations between animals and chemoautotrophic bacteria crowd around hydrothermal vents. In these associations, symbiotic bacteria use chemical reductants from venting fluid for the energy to support autotrophy, providing primary nutrition for the host. At vents along the Eastern Lau Spreading Center, the partially oxidized sulfur compounds (POSCs) thiosulfate and polysulfide have been detected in and around animal communities but away from venting fluid. The use of POSCs for autotrophy, as an alternative to the chemical substrates in venting fluid, could mitigate competition in these communities. To determine whether ESLC symbioses could use thiosulfate to support carbon fixation or produce POSCs during sulfide oxidation, we used high-pressure, flow-through incubations to assess the productivity of three symbiotic mollusc genera—the snails Alviniconcha spp. and Ifremeria nautilei , and the mussel Bathymodiolus brevior —when oxidizing sulfide and thiosulfate. Via the incorporation of isotopically labelled inorganic carbon, we found that the symbionts of all three genera supported autotrophy while oxidizing both sulfide and thiosulfate, though at different rates. Additionally, by concurrently measuring their effect on sulfur compounds in the aquaria with voltammetric microelectrodes, we showed that these symbioses excreted POSCs under highly sulfidic conditions, illustrating that these symbioses could represent a source for POSCs in their habitat. Furthermore, we revealed spatial disparity in the rates of carbon fixation among the animals in our incubations, which might have implications for the variability of productivity in situ . Together, these results re-shape our thinking about sulfur cycling and productivity by vent symbioses, demonstrating that thiosulfate may be an ecologically important energy source for vent symbioses and that they also likely impact the local geochemical regime through the excretion of POSCs.

scholarly journals Group-Specific Carbon Fixation Activity Measurements Reveal Distinct Responses to Oxygen Among Hydrothermal vent Campylobacteria

2020 ◽  
Author(s):  
Jesse McNichol ◽  
Stefan Dyksma ◽  
Marc Mußmann ◽  
Jeffrey S. Seewald ◽  
Sean P. Sylva ◽  
...  
Keyword(s):  
Community Composition ◽  
Deep Sea ◽  
Hydrothermal Vent ◽  
Hydrothermal Vents ◽  
Carbon Fixation ◽  
Genomic Diversity ◽  
Sequence Variant ◽  
Activity Measurements ◽  
Initial Starting

AbstractMolecular surveys of low temperature deep-sea hydrothermal vent fluids have shown that Campylobacteria (prev. Epsilonproteobacteria) often dominate the microbial community and that three subgroups - Arcobacter, Sulfurimonas and Sulfurovum - frequently coexist. In this study, we used replicated radiocarbon incubations of deep-sea hydrothermal fluids to investigate the activities of each group under three distinct incubation conditions. In order to quantify group-specific radiocarbon incorporation, we used newly designed oligonucleotide probes for Arcobacter, Sulfurimonas, and Sulfurovum to quantify their activity using catalyzed-reporter deposition fluorescence in-situ hybridization (CARD-FISH) combined with fluorescence-activated cell sorting. All three groups actively fixed CO2 in short-term (~ 20 h) incubations with either nitrate, oxygen, or no additions (control) at similar per-cell carbon fixation rates. Oxygen additions had the largest effect on community composition and overall cell numbers, and caused a pronounced shift in community composition at the amplicon sequence variant (ASV) level after only 20 h of incubation for all three groups. Interestingly, the effect of oxygen on carbon fixation rates appeared to depend on the initial starting community. Higher carbon fixation rates in oxygen-amended treatments were noted for all three taxa after an unintended disturbance to the sample site that may have selected for more oxygen-tolerant phylotypes. When viewed from a coarse taxonomic level, our data support assertions that these chemoautotrophic groups are functionally redundant in terms of their core metabolic capabilities since they were simultaneously active under all incubation conditions. In contrast, the higher resolution of amplicon sequencing allowed us to reveal finer-scale differences in growth that likely reflect adaptation of physiologically-distinct subtypes to varying oxygen concentrations in situ. Despite this progress, we still know remarkably little about the factors that maintain genomic diversity and allow for stable co-existence among these three campylobacterial groups. Moving forward, we suggest that more subtle biological factors such as enzyme substrate specificity, motility, cell morphology, and tolerance to environmental stress should be more thoroughly investigated to better understand ecological niche differentiation at deep-sea hydrothermal vents.

scholarly journals In Situ Determination of Sulfide Turnover Rates in a Meromictic Alpine Lake

2000 ◽  
Vol 66 (2) ◽  
pp. 712-717 ◽  
Author(s):  
Lucas Lüthy ◽  
Markus Fritz ◽  
Reinhard Bachofen
Keyword(s):  
Sulfide Oxidation ◽  
Chemical Oxidation ◽  
Bacterial Photosynthesis ◽  
Sulfur Compounds ◽  
Turnover Rates ◽  
Sulfide Production ◽  
Chemolithotrophic Bacteria ◽  
Different Depths

ABSTRACT A push-pull method, previously used in groundwater analyses, was successfully adapted for measuring sulfide turnover rates in situ at different depths in the meromictic Lake Cadagno. In the layer of phototrophic bacteria at about 12 m in depth net sulfide consumption was observed during the day, indicating active bacterial photosynthesis. During the night the sulfide turnover rates were positive, indicating a net sulfide production from the reduction of more-oxidized sulfur compounds. Because of lack of light, no photosynthesis takes place in the monimolimnion; thus, only sulfide formation is observed both during the day and the night. Sulfide turnover rates in the oxic mixolimnion were always positive as sulfide is spontaneously oxidized by oxygen and as the rates of sulfide oxidation depend on the oxygen concentrations present. Sulfide oxidation by chemolithotrophic bacteria may occur at the oxicline, but this cannot be distinguished from spontaneous chemical oxidation.

scholarly journals Validating the Cyc2 neutrophilic Fe oxidation pathway using meta-omics of Zetaproteobacteria iron mats at marine hydrothermal vents

2019 ◽  
Author(s):  
Sean M. McAllister ◽  
Shawn W. Polson ◽  
David A. Butterfield ◽  
Brian T. Glazer ◽  
Jason B. Sylvan ◽  
...  
Keyword(s):  
Hydrothermal Vents ◽  
Carbon Fixation ◽  
Central Metabolism ◽  
Ideal Model ◽  
Oxidase Gene ◽  
Oxidation Pathway ◽  
Fe Oxidation ◽  
Mid Atlantic Ridge ◽  
Metabolism Gene

AbstractZetaproteobacteria create extensive iron (Fe) oxide mats at marine hydrothermal vents, making them an ideal model for microbial Fe oxidation at circumneutral pH. Comparison of neutrophilic Fe-oxidizer isolate genomes has revealed a hypothetical Fe oxidation pathway, featuring a homolog of the Fe oxidase Cyc2 from Acidithiobacillus ferrooxidans. However, Cyc2 function is not well verified in neutrophilic Fe-oxidizers, particularly in Fe-oxidizing environments. Toward this, we analyzed genomes and metatranscriptomes of Zetaproteobacteria, using 53 new high-quality metagenome assembled genomes reconstructed from Fe mats at Mid-Atlantic Ridge, Mariana Backarc, and Loihi Seamount (Hawaii) hydrothermal vents. Phylogenetic analysis demonstrated conservation of Cyc2 sequences among most neutrophilic Fe-oxidizers, suggesting a common function. We confirmed the widespread distribution of cyc2 and other model Fe oxidation pathway genes across all represented Zetaproteobacteria lineages. High expression of these genes was observed in diverse Zetaproteobacteria under multiple environmental conditions, and in incubations. The putative Fe oxidase gene, cyc2, was highly expressed in situ, often as the top expressed gene. The cyc2 gene showed increased expression in Fe(II)-amended incubations, with corresponding increases in carbon fixation and central metabolism gene expression. These results substantiate the Cyc2-based Fe oxidation pathway in neutrophiles and demonstrate its significance in marine Fe-mineralizing environments.

Genus-Specific Carbon Fixation Activity Measurements Reveal Distinct Responses to Oxygen Among Hydrothermal Vent Campylobacteria

2021 ◽  
Author(s):  
Jesse McNichol ◽  
Stefan Dyksma ◽  
Marc Mußmann ◽  
Jeffrey S. Seewald ◽  
Sean P. Sylva ◽  
...  
Keyword(s):  
Community Composition ◽  
Deep Sea ◽  
Hydrothermal Vent ◽  
Hydrothermal Vents ◽  
Carbon Fixation ◽  
Sequence Variant ◽  
Experimental Conditions ◽  
Activity Measurements ◽  
Initial Starting

Molecular surveys of low temperature deep-sea hydrothermal vent fluids have shown that Campylobacteria (prev. Epsilonproteobacteria ) often dominate the microbial community and that three genera - Arcobacter , Sulfurimonas and Sulfurovum - frequently coexist. In this study, we used replicated radiocarbon incubations of deep-sea hydrothermal fluids to investigate activity of each genus under three experimental conditions. To quantify genus-specific radiocarbon incorporation, we used newly designed oligonucleotide probes for Arcobacter , Sulfurimonas , and Sulfurovum to quantify their activity using catalyzed-reporter deposition fluorescence in-situ hybridization (CARD-FISH) combined with fluorescence-activated cell sorting. All three genera actively fixed CO 2 in short-term (∼ 20 h) incubations, but responded differently to the additions of nitrate and oxygen. Oxygen additions had the largest effect on community composition, and caused a pronounced shift in community composition at the amplicon sequence variant (ASV) level after only 20 h of incubation. The effect of oxygen on carbon fixation rates appeared to depend on the initial starting community. The presented results support the hypothesis that these chemoautotrophic genera possess functionally redundant core metabolic capabilities, but also reveal finer-scale differences in growth likely reflecting adaptation of physiologically-distinct phylotypes to varying oxygen concentrations in situ . Overall, our study provides new insights into how oxygen controls community composition and total chemoautotrophic activity, and underscores how quickly deep-sea vent microbial communities respond to disturbances. Importance: Sulfidic environments worldwide are often dominated by sulfur-oxidizing, carbon-fixing Campylobacteria . Environmental factors associated with this group's dominance are now understood, but far less is known about the ecology and physiology of members of subgroups of chemoautotrophic Campylobacteria . In this study, we used a novel method to differentiate the genus-specific chemoautotrophic activity of three subtypes of Campylobacteria. In combination with evidence from microscopic counts, chemical consumption/production during incubations, and DNA-based measurements, our data show that oxygen concentration affects both community composition and chemoautotrophic function in situ . These results help us better understand factors controlling microbial diversity at deep-sea hydrothermal vents, and provide first-order insights into the ecophysiological differences between these distinct microbial taxa.

Functional response of Fucus vesiculosus communities to tributyltin measured in an in situ continuous flow-through system

Hydrobiologia ◽  
1989 ◽  
Vol 188-189 (1) ◽  
pp. 277-283 ◽  
Author(s):  
C. Lindblad ◽  
U. Kautsky ◽  
C. André ◽  
N. Kautsky ◽  
M. Tedengren
Keyword(s):  
Functional Response ◽  
Continuous Flow ◽  
Fucus Vesiculosus ◽  
Flow Through

Simple flow through reaction cells for in situ transmission and fluorescence x-ray-absorption spectroscopy of heterogeneous catalysts

2006 ◽  
Vol 77 (2) ◽  
pp. 023105 ◽  
Author(s):  
Simon R. Bare ◽  
George E. Mickelson ◽  
Frank S. Modica ◽  
Andrzej Z. Ringwelski ◽  
N. Yang
Keyword(s):  
Absorption Spectroscopy ◽  
Heterogeneous Catalysts ◽  
X Ray ◽  
Flow Through ◽  
X Ray Absorption ◽  
Simple Flow

In situ determination of porewater gases by underwater flow-through membrane inlet mass spectrometry

2012 ◽  
Vol 10 (3) ◽  
pp. 117-128 ◽  
Author(s):  
Ryan J. Bell ◽  
William B. Savidge ◽  
Strawn K. Toler ◽  
Robert H. Byrne ◽  
R. Timothy Short
Keyword(s):  
Mass Spectrometry ◽  
Membrane Inlet Mass Spectrometry ◽  
Flow Through

In Situ Enhancement of Flow-through Porous Electrodes with Carbon Nanotubes via Flowing Deposition

2016 ◽  
Vol 206 ◽  
pp. 36-44 ◽  
Author(s):  
Marc-Antoni Goulet ◽  
Aronne Habisch ◽  
Erik Kjeang
Keyword(s):  
Carbon Nanotubes ◽  
Porous Electrodes ◽  
Flow Through

scholarly journals Niche partitioning in the Rimicaris exoculata holobiont: the case of the first symbiotic Zetaproteobacteria

Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Marie-Anne Cambon-Bonavita ◽  
Johanne Aubé ◽  
Valérie Cueff-Gauchard ◽  
Julie Reveillaud
Keyword(s):  
Hydrothermal Vents ◽  
Carbon Fixation ◽  
Iron Sulfide ◽  
Hydrogen Oxidation ◽  
Niche Partitioning ◽  
Sulfur Oxidation ◽  
Single Copy ◽  
Trophic Levels ◽  
Rimicaris Exoculata ◽  
Close Relatives

Abstract Background Free-living and symbiotic chemosynthetic microbial communities support primary production and higher trophic levels in deep-sea hydrothermal vents. The shrimp Rimicaris exoculata, which dominates animal communities along the Mid-Atlantic Ridge, houses a complex bacterial community in its enlarged cephalothorax. The dominant bacteria present are from the taxonomic groups Campylobacteria, Desulfobulbia (formerly Deltaproteobacteria), Alphaproteobacteria, Gammaproteobacteria, and some recently discovered iron oxyhydroxide-coated Zetaproteobacteria. This epibiotic consortium uses iron, sulfide, methane, and hydrogen as energy sources. Here, we generated shotgun metagenomes from Rimicaris exoculata cephalothoracic epibiotic communities to reconstruct and investigate symbiotic genomes. We collected specimens from three geochemically contrasted vent fields, TAG, Rainbow, and Snake Pit, to unravel the specificity, variability, and adaptation of Rimicaris–microbe associations. Results Our data enabled us to reconstruct 49 metagenome-assembled genomes (MAGs) from the TAG and Rainbow vent fields, including 16 with more than 90% completion and less than 5% contamination based on single copy core genes. These MAGs belonged to the dominant Campylobacteria, Desulfobulbia, Thiotrichaceae, and some novel candidate phyla radiation (CPR) lineages. In addition, most importantly, two MAGs in our collection were affiliated to Zetaproteobacteria and had no close relatives (average nucleotide identity ANI < 77% with the closest relative Ghiorsea bivora isolated from TAG, and 88% with each other), suggesting potential novel species. Genes for Calvin-Benson Bassham (CBB) carbon fixation, iron, and sulfur oxidation, as well as nitrate reduction, occurred in both MAGs. However, genes for hydrogen oxidation and multicopper oxidases occurred in one MAG only, suggesting shared and specific potential functions for these two novel Zetaproteobacteria symbiotic lineages. Overall, we observed highly similar symbionts co-existing in a single shrimp at both the basaltic TAG and ultramafic Rainbow vent sites. Nevertheless, further examination of the seeming functional redundancy among these epibionts revealed important differences. Conclusion These data highlight microniche partitioning in the Rimicaris holobiont and support recent studies showing that functional diversity enables multiple symbiont strains to coexist in animals colonizing hydrothermal vents.

scholarly journals In-Situ Metatranscriptomic Analyses Reveal the Metabolic Flexibility of the Thermophilic Anoxygenic Photosynthetic Bacterium Chloroflexusaggregans in a Hot Spring Cyanobacteria-Dominated Microbial Mat

2021 ◽  
Vol 9 (3) ◽  
pp. 652
Author(s):  
Shigeru Kawai ◽  
Joval N. Martinez ◽  
Mads Lichtenberg ◽  
Erik Trampe ◽  
Michael Kühl ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Environmental Conditions ◽  
Microbial Mats ◽  
Carbon Fixation ◽  
Hot Springs ◽  
Hot Spring ◽  
Photosynthetic Bacterium ◽  
Early Morning ◽  
Metabolic Flexibility

Chloroflexus aggregans is a metabolically versatile, thermophilic, anoxygenic phototrophic member of the phylum Chloroflexota (formerly Chloroflexi), which can grow photoheterotrophically, photoautotrophically, chemoheterotrophically, and chemoautotrophically. In hot spring-associated microbial mats, C. aggregans co-exists with oxygenic cyanobacteria under dynamic micro-environmental conditions. To elucidate the predominant growth modes of C. aggregans, relative transcription levels of energy metabolism- and CO2 fixation-related genes were studied in Nakabusa Hot Springs microbial mats over a diel cycle and correlated with microscale in situ measurements of O2 and light. Metatranscriptomic analyses indicated two periods with different modes of energy metabolism of C. aggregans: (1) phototrophy around midday and (2) chemotrophy in the early morning hours. During midday, C. aggregans mainly employed photoheterotrophy when the microbial mats were hyperoxic (400–800 µmol L−1 O2). In the early morning hours, relative transcription peaks of genes encoding uptake hydrogenase, key enzymes for carbon fixation, respiratory complexes as well as enzymes for TCA cycle and acetate uptake suggest an aerobic chemomixotrophic lifestyle. This is the first in situ study of the versatile energy metabolism of C. aggregans based on gene transcription patterns. The results provide novel insights into the metabolic flexibility of these filamentous anoxygenic phototrophs that thrive under dynamic environmental conditions.

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