Rapid Microbial Production of Filamentous Sulfur Mats at Hydrothermal Vents

ABSTRACT During recent oceanographic cruises to Pacific hydrothermal vent sites (9°N and the Guaymas Basin), the rapid microbial formation of filamentous sulfur mats by a new chemoautotrophic, hydrogen sulfide-oxidizing bacterium was documented in both in situ and shipboard experiments. Observations suggest that formation of these sulfur mats may be a factor in the initial colonization of hydrothermal surfaces by macrofaunal Alvinella worms. This novel metabolic capability, previously shown to be carried out by a coastal strain in H2S continuous-flow reactors, may be an important, heretofore unconsidered, source of microbial organic matter production at deep-sea hydrothermal vents.

Download Full-text

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

10.1101/2020.11.29.402834 ◽

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.

Download Full-text

Scalable in Situ Diazomethane Generation in Continuous-Flow Reactors

Organic Process Research & Development ◽

10.1021/op200110a ◽

2011 ◽

Vol 16 (5) ◽

pp. 1146-1149 ◽

Cited By ~ 50

Author(s):

Emiliano Rossi ◽

Pierre Woehl ◽

Michele Maggini

Keyword(s):

Continuous Flow ◽

Flow Reactors ◽

Continuous Flow Reactors

Download Full-text

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

Applied and Environmental Microbiology ◽

10.1128/aem.02083-21 ◽

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.

Download Full-text

Reductive amination of levulinic acid or its derivatives to pyrrolidones over heterogeneous catalysts in the batch and continuous flow reactors: A review

Renewable and Sustainable Energy Reviews ◽

10.1016/j.rser.2021.110876 ◽

2021 ◽

Vol 143 ◽

pp. 110876

Author(s):

M.V. Bukhtiyarova ◽

G.A. Bukhtiyarova

Keyword(s):

Continuous Flow ◽

Levulinic Acid ◽

Heterogeneous Catalysts ◽

Reductive Amination ◽

Flow Reactors ◽

Continuous Flow Reactors

Download Full-text

Continuous flow reactors: a perspective

Green Chemistry ◽

10.1039/c1gc16022b ◽

2012 ◽

Vol 14 (1) ◽

pp. 38-54 ◽

Cited By ~ 430

Author(s):

Charlotte Wiles ◽

Paul Watts

Keyword(s):

Continuous Flow ◽

Flow Reactors ◽

Continuous Flow Reactors

Download Full-text

Development of an Easy-to-Operate Underwater Raman System for Deep-Sea Cold Seep and Hydrothermal Vent In Situ Detection

Sensors ◽

10.3390/s21155090 ◽

2021 ◽

Vol 21 (15) ◽

pp. 5090

Author(s):

Qingsheng Liu ◽

Jinjia Guo ◽

Wangquan Ye ◽

Kai Cheng ◽

Fujun Qi ◽

...

Keyword(s):

Deep Sea ◽

Hydrothermal Vent ◽

Methane Hydrate ◽

Sulfur Cycle ◽

Cold Seep ◽

Remotely Operated Vehicle ◽

Bacterial Mats ◽

Optical Module ◽

In Situ Detection

As a powerful in situ detection technique, Raman spectroscopy is becoming a popular underwater investigation method, especially in deep-sea research. In this paper, an easy-to-operate underwater Raman system with a compact design and competitive sensitivity is introduced. All the components, including the optical module and the electronic module, were packaged in an L362 × Φ172 mm titanium capsule with a weight of 20 kg in the air (about 12 kg in water). By optimising the laser coupling mode and focusing lens parameters, a competitive sensitivity was achieved with the detection limit of SO42− being 0.7 mmol/L. The first sea trial was carried out with the aid of a 3000 m grade remotely operated vehicle (ROV) “FCV3000” in October 2018. Over 20,000 spectra were captured from the targets interested, including methane hydrate, clamshell in the area of cold seep, and bacterial mats around a hydrothermal vent, with a maximum depth of 1038 m. A Raman peak at 2592 cm−1 was found in the methane hydrate spectra, which revealed the presence of hydrogen sulfide in the seeping gas. In addition, we also found sulfur in the bacterial mats, confirming the involvement of micro-organisms in the sulfur cycle in the hydrothermal field. It is expected that the system can be developed as a universal deep-sea survey and detection equipment in the near future.

Download Full-text

Design and analysis of continuous-flow reactors for copper sulfide precipitation process by a computational method

Environmental Science and Pollution Research ◽

10.1007/s11356-019-06512-0 ◽

2019 ◽

Vol 26 (33) ◽

pp. 34531-34551 ◽

Cited By ~ 2

Author(s):

Zhihui Yang ◽

Bo Li ◽

Weizhi Zeng ◽

Ken Li ◽

Shan Liu ◽

...

Keyword(s):

Copper Sulfide ◽

Continuous Flow ◽

Computational Method ◽

Precipitation Process ◽

Flow Reactors ◽

Sulfide Precipitation ◽

Continuous Flow Reactors

Download Full-text

Growth and Phylogenetic Properties of Novel Bacteria Belonging to the Epsilon Subdivision of the Proteobacteria Enriched fromAlvinella pompejana and Deep-Sea Hydrothermal Vents

Applied and Environmental Microbiology ◽

10.1128/aem.67.10.4566-4572.2001 ◽

2001 ◽

Vol 67 (10) ◽

pp. 4566-4572 ◽

Cited By ~ 102

Author(s):

Barbara J. Campbell ◽

Christian Jeanthon ◽

Joel E. Kostka ◽

George W. Luther ◽

S. Craig Cary

Keyword(s):

Deep Sea ◽

Hydrothermal Vent ◽

Hydrothermal Vents ◽

Heterotrophic Bacteria ◽

Geographic Location ◽

Optimal Growth ◽

Small Subunit ◽

Ribosomal Gene ◽

Moderately Thermophilic ◽

Novel Bacteria

ABSTRACT Recent molecular characterizations of microbial communities from deep-sea hydrothermal sites indicate the predominance of bacteria belonging to the epsilon subdivision of Proteobacteria(epsilon Proteobacteria). Here, we report the first enrichments and characterizations of four epsilonProteobacteria that are directly associated withAlvinella pompejana, a deep sea hydrothermal vent polychete, or with hydrothermal vent chimney samples. These novel bacteria were moderately thermophilic sulfur-reducing heterotrophs growing on formate as the energy and carbon source. In addition, two of them (Am-H and Ex-18.2) could grow on sulfur lithoautrotrophically using hydrogen as the electron donor. Optimal growth temperatures of the bacteria ranged from 41 to 45°C. Phylogenetic analysis of the small-subunit ribosomal gene of the two heterotrophic bacteria demonstrated 95% similarity to Sulfurospirillum arcachonense, an epsilon Proteobacteria isolated from an oxidized marine surface sediment. The autotrophic bacteria grouped within a deeply branching clade of the epsilonProteobacteria, to date composed only of uncultured bacteria detected in a sample from a hydrothermal vent along the mid-Atlantic ridge. A molecular survey of various hydrothermal vent environments demonstrated the presence of two of these bacteria (Am-N and Am-H) in more than one geographic location and habitat. These results suggest that certain epsilonProteobacteria likely fill important niches in the environmental habitats of deep-sea hydrothermal vents, where they contribute to overall carbon and sulfur cycling at moderate thermophilic temperatures.

Download Full-text

Pressure and Temperature Adaptation of Cytosolic Malate Dehydrogenases of Shallowand Deep-Living Marine Invertebrates: Evidence for High Body Temperatures in Hydrothermal Vent Animals

Journal of Experimental Biology ◽

10.1242/jeb.159.1.473 ◽

1991 ◽

Vol 159 (1) ◽

pp. 473-487 ◽

Cited By ~ 2

Author(s):

ELIZABETH DAHLHOFF ◽

GEORGE N. SOMERO

Keyword(s):

Deep Sea ◽

Hydrothermal Vents ◽

Elevated Temperatures ◽

Marine Invertebrates ◽

Distribution Patterns ◽

Pressure Effects ◽

Temperature Adaptation ◽

Body Temperatures ◽

Elevated Pressures

Effects of temperature and hydrostatic pressure were measured on cytosolic malate dehydrogenases (cMDHs) from muscle tissue of a variety of shallow- and deep-living benthic marine invertebrates, including seven species endemic to the deep-sea hydrothermal vents. The apparent Michaelis-Menten constant (Km) of coenzyme (nicotinamide adenine dinucleotide, NADH), used to index temperature and pressure effects, was conserved within a narrow range (approximately 15–25 μmoll−1) at physiological temperatures and pressures for all species. However, at elevated pressures, the Km of NADH rose sharply for cMDHs of shallow species (depths of occurrence >Approximately 500 m), but not for the cMDHs of deep-sea species. Cytosolic MDHs of invertebrates from the deep-sea hydrothermal vents generally were not perturbed by elevated temperatures (15–25°C) at in situ pressures, but cMDHs of cold-adapted deep-sea species were. At a single measurement temperature, the Km of NADH for cMDHs from invertebrates from habitats with well-characterized temperatures was inversely related to maximal sustained body temperature. This correlation was used to predict the maximal sustained body temperatures of vent invertebrates for which maximal habitat and body temperatures are difficult to estimate. Species occurring on the ‘smoker chimneys’, which emit waters with temperatures up to 380°C, are predicted to have sustained body temperatures that are approximately 20–25°C higher than vent species living in cooler vent microhabitats. We conclude that, just as adaptation of enzymes to elevated pressures is important in establishing species’ depth distribution patterns, adaptation of pressure-adapted enzymes to temperature is critical in enabling certain vent species to exploit warm-water microhabitats in the vent environment.

Download Full-text