We investigated the impact of pressure on thermophilic, chemolithoautotrophic NO3− reducing bacteria of the phyla Campylobacterota and Aquificota isolated from deep-sea hydrothermal vents. Batch incubations at 5 and 20 MPa resulted in decreased NO3− consumption, lower cell concentrations, and overall slower growth in Caminibacter mediatlanticus (Campylobacterota) and Thermovibrio ammonificans (Aquificota), relative to batch incubations near standard pressure (0.2 MPa) conditions. Nitrogen isotope fractionation effects from chemolithoautotrophic NO3− reduction by both microorganisms were, on the contrary, maintained under all pressure conditions. Comparable chemolithoautotrophic NO3− reducing activities between previously reported natural hydrothermal vent fluid microbial communities dominated by Campylobacterota at 25 MPa and Campylobacterota laboratory isolates at 0.2 MPa, suggest robust similarities in cell-specific NO3− reduction rates and doubling times between microbial populations and communities growing maximally under similar temperature conditions. Physiological and metabolic comparisons of our results with other studies of pressure effects on anaerobic chemolithoautotrophic processes (i.e., microbial S0-oxidation coupled to Fe(III) reduction and hydrogenotrophic methanogenesis) suggest that anaerobic chemolithoautotrophs relying on oxidation–reduction (redox) reactions that yield higher Gibbs energies experience larger shifts in cell-specific respiration rates and doubling times at increased pressures. Overall, our results advance understanding of the role of pressure, its relationship with temperature and redox conditions, and their effects on seafloor chemolithoautotrophic NO3− reduction and other anaerobic chemolithoautotrophic processes.
Microbial sulfur cycling in marine sediments often occurs in environments characterized by transient chemical gradients that affect both the availability of nutrients and the activity of microbes. High turnover rates of intermediate valence sulfur compounds and the intermittent availability of oxygen in these systems greatly impact the activity of sulfur‐oxidizing micro‐organisms in particular. In this study, the thiosulfate‐oxidizing hydrothermal vent bacterium Thiomicrospira thermophila strain EPR85 was grown in continuous culture at a range of dissolved oxygen concentrations (0.04–1.9 mM) and high pressure (5–10 MPa) in medium buffered at pH 8. Thiosulfate oxidation under these conditions produced tetrathionate, sulfate, and elemental sulfur, in contrast to previous closed‐system experiments at ambient pressure during which thiosulfate was quantitatively oxidized to sulfate. The maximum observed specific growth rate at 5 MPa pressure under unlimited O2 was 0.25 hr−1. This is comparable to the μmax (0.28 hr−1) observed at low pH (<6) at ambient pressure when T. thermophila produces the same mix of sulfur species. The half‐saturation constant for O2 (KO2) estimated from this study was 0.2 mM (at a cell density of 105 cells/ml) and was robust at all pressures tested (0.4–10 MPa), consistent with piezotolerant behavior of this strain. The cell‐specific KO2 was determined to be 1.5 pmol O2/cell. The concentrations of products formed were correlated with oxygen availability, with tetrathionate production in excess of sulfate production at all pressure conditions tested. This study provides evidence for transient sulfur storage during times when substrate concentration exceeds cell‐specific KO2 and subsequent consumption when oxygen dropped below that threshold. These results may be common among sulfur oxidizers in a variety of environments (e.g., deep marine sediments to photosynthetic microbial mats).
In this study, we integrated geochemical measurements, microbial diversity surveys and physiological characterization of laboratory strains to investigate substrate-attached filamentous microbial biofilms at Tor Caldara, a shallow-water gas vent in the Tyrrhenian Sea. At this site, the venting gases are mainly composed of CO2 and H2S and the temperature at the emissions is the same as that of the surrounding water. To investigate the composition of the total and active fraction of the Tor Caldara biofilm communities, we collected established and newly formed filaments and we sequenced the 16S rRNA genes (DNA) and the 16S rRNA transcripts (cDNA). Chemoautotrophic sulfur-oxidizing members of the Gammaproteobacteria (predominantly Thiotrichales) dominate the active fraction of the established microbial filaments, while Epsilonproteobacteria (predominantly Sulfurovum spp.) are more prevalent in the young filaments. This indicates a succession of the two communities, possibly in response to age, sulfide and oxygen concentrations. Growth experiments with representative laboratory strains in sulfide gradient medium revealed that Sulfurovum riftiae (Epsilonproteobacteria) grew closer to the sulfide source than Thiomicrospirasp. (Gammaproteobacteria, Thiotrichales). Overall, our findings show that sulfur-oxidizing Epsilonproteobacteria are the dominant pioneer colonizers of the Tor Caldara biofilm communities and that Gammaproteobacteria become prevalent once the community is established. This succession pattern appears to be driven – among other factors – by the adaptation of Epsilon– and Gammaproteobacteria to different sulfide concentrations.
Chemolithoautotrophic microorganisms use inorganic molecules such as H2 or H2S as energy sources to drive carbon fixation from CO2 into biomass. Such organisms dominate the microbiota of deep-sea hydrothermal vents, where they are well adapted to elevated pressure, sharp thermal gradients, and highly variable redox conditions. Considering the contribution of these microbial communities to the global biogeochemical cycles, it is striking how little we know about the function and physiological responses of piezophiles to physical and chemical conditions resembling deep-sea habitats. Here, we conducted a series of high-pressure culture to gain insight into the adaptation mechanisms of piezophilic microorganisms to the environmental and bioenergetics conditions of subsurface biosphere. The model organism is a strictly anaerobic, nitrate reducing, thermophilic Epsilonproteobacterium (Nautilia strain PV-1) that we recently isolated from fluids discharged from an active deep-sea vent at the East Pacific Rise. This novel deep-sea vent bacterium is the only autotrophic organism among the piezophilic organisms isolated. Genomic and proteomic analysis revealed that the PV-1’s adaptation strategies under high pressure may involve upregulation of genes encoding for membrane fluidity, ATP transport, motility and production/conservation of energy, competence along with the downregulation of enzymes linked to the reductive citric acid cycle. Adaptation strategies to pressure and bioenergetic stresses may also be closely related to the presence of a temperate bacteriophage in the genome of PV-1. In the course of this project, we also investigated the physiology and functions of a suite of deep-sea and shallow-water chemolithoautrophic bacteria as both pure and mixed environmental cultures.
NO3– reduction is a metabolism that is widespread among ε-Proteobacteria and Aquificae, two abundant classes of microorganisms found at deep-sea vents. In this study, we used Sulfurovum lithotrophicum, Caminibacter mediatlanticus and Thermovibrio ammonificans as representatives of these groups to study ecophysiological, metabolic and biogeochemical parameters associated with chemolithoautotrophic NO3– reduction under different temperature regimes. We observed that while S. lithotrophicum and C. mediatlanticus achieved higher cell densities than T. ammonificans, the overall NO3– consumption by the latter was on average ∼ 9 and ∼ 5 times faster on a per cell basis, respectively. Comparison with previously published data from other cultured vent ε-Proteobacteria and Aquificae suggests that the rate-yield trade-offs observed in our experiments are generally conserved between these two groups in line with their ecophysiologies. Kinetic isotope effects of N from NO3– reduction were 9.6 ± 2.7 ‰ for S. lithotrophicum, 6.4 ± 0.7 ‰ for C. mediatlanticus and 8.8 ± 0.6 ‰ for T. ammonificans. Our results help evaluate how metabolic partitioning between growth efficiency and reaction kinetics during chemolithoautotrophic NO3– reduction affect the concentration and isotope composition of N compounds at deep-sea hydrothermal vents.
We report measurements of resolved 12CH2D2 and 13CH3D at natural abundances in a variety of methane gases produced naturally and in the laboratory. The ability to resolve 12CH2D2 from 13CH3D provides unprecedented insights into the origin and evolution of CH4. The results identify conditions under which either isotopic bond order disequilibrium or equilibrium are expected. Where equilibrium obtains, concordant Δ12CH2D2 and Δ13CH3D temperatures can be used reliably for thermometry. We find that concordant temperatures do not always match previous hypotheses based on indirect estimates of temperature of formation nor temperatures derived from CH4/H2 D/H exchange, underscoring the importance of reliable thermometry based on the CH4 molecules themselves. Where Δ12CH2D2 and Δ13CH3D values are inconsistent with thermodynamic equilibrium, temperatures of formation derived from these species are spurious. In such situations, while formation temperatures are unavailable, disequilibrium isotopologue ratios nonetheless provide novel information about the formation mechanism of the gas and the presence or absence of multiple sources or sinks. In particular, disequilibrium isotopologue ratios may provide the means for differentiating between methane produced by abiotic synthesis vs. biological processes. Deficits in 12CH2D2 compared with equilibrium values in CH4 gas made by surface-catalyzed abiotic reactions are so large as to point towards a quantum tunneling origin. Tunneling also accounts for the more moderate depletions in 13CH3D that accompany the low 12CH2D2 abundances produced by abiotic reactions. The tunneling signature may prove to be an important tracer of abiotic methane formation, especially where it is preserved by dissolution of gas in cool hydrothermal systems (e.g., Mars). Isotopologue signatures of abiotic methane production can be erased by infiltration of microbial communities, and Δ12CH2D2 values are a key tracer of microbial recycling.
| URL | https://www.bco-dmo.org/dataset/474322 |
|---|---|
| Download URL | https://www.bco-dmo.org/dataset/474322/data/download |
| Media Type | text/tab-separated-values |
| Created | January 13, 2014 |
| Modified | August 19, 2016 |
| State | Final no updates expected |
| Brief Description | Concentrations of anions, cations, and trace elements/metals from vents near Milos I., Greece. |
Fluid samples were collected from the water column close to the shallow-water venting sites and from the interstitial waters of all cores at 2 cm intervals. Fluids and gases were also sampled from the subaerial sites. Samples returned to the Geophysical Lab were analyzed to determine dissolved concentrations of: organic acids and a range of major anions/cations species (e.g. SO42-, PO42-, SNH3, NO3-, Cl-, Na+, K+, Ca2+, and Mg2+) including trace elements and metals. We used ion chromatography (Metrohm “MIC-3 Advanced IC, Metrosep A supp 7-250/16-250; C4- 250 columns). Fluids were analyzed for metal and trace element concentrations at the MC-ICP-MS facility of Prof. Michael Bizimis at the University of South Carolina.
Relevant References:
Mustafa Yücel, Stefan M. Sievert, Costantino Vetriani, Dionysis I. Foustoukos, Donato Giovannelli, Nadine Le Bris. Eco-geochemical dynamics of a shallow-water hydrothermal vent system at Milos Island, Aegean Sea (Eastern Mediterranean). Chemical Geology 356 (2013) 11-20.
Hand-held temperature probe
date; generally reported in GMT as YYYYMMDD (year; month; day); also as MMDD (month; day); EqPac dates are local Hawaii time. ISO_Date format is YYYY-MM-DD (http://www.iso.org/iso/home/standards/iso8601.htm)
latitude, in decimal degrees, North is positive, negative denotes South; Reported in some datasets as degrees, minutes
longitude, in decimal degrees, East is positive, negative denotes West; Reported in some datsets as degrees, minutes
Observation/sample depth below the sea surface. Units often reported as: meters, feet.
When used in a JGOFS/GLOBEC dataset the depth is a best estimate; usually but not always calculated from pressure; calculated either from CTD pressure using Fofonoff and Millard (1982; UNESCO Tech Paper #44) algorithm adjusted for 1980 equation of state for seawater (EOS80) or simply equivalent to nominal depth as recorded during sampling if CTD pressure was unavailable.
unique sample identification or number; any combination of alpha numeric characters; precise definition is file dependent
Ammonium and ammonia concentration parameters in any body of fresh or salt water.
Nitrate concentration in the water column
Orthophosphate (phosphate, reactive phosphorus), Various units.
Concentration of sulfate (SO4) per unit volume
Cesium ion concentration as measured by the USC lab
Ba (Barium). May be reported in parts per million, nanomoles per Liter, or other units. Refer to dataset metadata for units.
Iron (Fe). Concentrations may be reported in parts per million, nanomoles per liter, or other units. Refer to dataset metadata for units.
| Name | Affiliation | Contact |
|---|---|---|
| Dionysis I. Foustoukos | Carnegie Institution for Science (CIS) | ✓ |
| Nancy Copley | Carnegie Institution for Science (CIS) | ✓ |
| Project Title | Autotrophic carbon fixation at a shallow-water hydrothermal system: Constraining microbial activity, isotopic and geochemical regimes |
|---|---|
| Acronym | Hydrothermal Autotrophic Carbon Fixation |
| URL | https://www.bco-dmo.org/project/473892 |
| Created | January 8, 2014 |
| Modified | June 3, 2015 |
In this project we studied the shallow-water hydrothermal vent sites at Milos Island (Greece) to better understand the extent of autotrophic carbon fixation and its chemical and isotopic signature along environmental (redox/thermal) gradients. This was a 12-day long expedition (May 18 to 30, 2012) to sample vent fluids, gases and retrieve sediment cores at Paleochori Bay by using SCUBA diving at 8-10 m depth. In addition to the submarine vent sites, two subaerial locations of venting were identified at 36o 40′ 28″N – 24o 31′ 14″ E and 36o 40′ 25″ N – 24o 30′ 44″ E. Both the subaerial and submarine sites are located on the same fracture zone that likely controls the hydrothermal circulation of evolved meteoritic water and seawater within the magmatic zone of Milos Island. To this end, the geochemistry of the fluids and gases emitted from subaerial sites provide important information towards identifying the linkage between the subaerial and submarine magmatic activity and provide insights on the metabolic functions (e.g. H2 oxidation, Fe(III) reduction, C and S cycling) of the subsurface microbial community.
Abstract:
Currently, there is only limited information on the identity and activity of the microorganisms carrying out CO2-fixation in situ, despite the fact that these organisms form the basis of their respective ecosystems. Representatives that are able to grow autotrophically are known to exist in almost all major groups of prokaryotes, and these organisms play essential roles in ecosystems by providing a continuous supply of organic carbon for heterotrophs. Microorganisms present in extreme environments utilize CO2- fixation pathways other than the Calvin-Benson-Bassham (CBB) cycle. At present, five alternative autotrophic CO2 fixation pathways are known. Different carbon fixation pathways result in distinct isotopic signatures of the produced biomass due to the isotopic discrimination between light (12C) and heavy (13C) carbon by the carboxylating enzymes. Thus, inferences about the carbon fixation pathway predominantly utilized by the microbial community can also be made based on the stable carbon isotopic composition of the organic matter, in extant systems as well as in the geological record. However, at present little is known about the systematics and extents of fractionation during carbon fixation by prokaryotic organisms, and to our knowledge no studies exist that have systematically studied the relationship between the operation of different carbon fixation pathways and how this is reflected in the stable carbon isotopic composition in a natural system. This is a 2-year interdisciplinary, international research program that employs a powerful combination of cutting-edge research tools aiming to improve our understanding of autotrophic carbon fixation and its chemical and isotopic signature along environmental gradients in a natural hydrothermal system. The following hypotheses are addressed:
1. The diversity of microorganisms present along a thermal and redox gradient, and rates of CO2 fixation, will reflect adaptation to in situ temperatures and geochemical conditions
2. Microorganisms utilizing the CBB cycle for autotrophic CO2-fixation will represent a smaller percentage of the chemolithoautotrophic community at higher temperatures, where microorganisms utilizing alternative CO2-fixation pathways dominate
3. Isotopic values of biomass and specific biomarker molecules will vary along a thermal and redox gradient from zones characterized by a higher hydrothermal fluid flux and thus higher temperatures to the surrounding, cooler areas, corresponding to the physiology of the microorganisms utilizing different pathways for carbon fixation
The PIs will use a multidisciplinary approach to delineate the relative contribution of the different carbon fixation pathways along an environmental gradient by combining metagenomic analyses coupled with: 1) an assessment of the frequency and the expression of specific key genes involved in carbon fixation, and 2) with the measurement of carbon fixation rates. These data will be integrated with the determination of stable C isotopic composition of biomass, DIC, and specific hydrocarbons/lipids. Due to its easy accessibility, well-established environmental gradients, and extensive background information, the shallow-water vents off Milos (Greece) will be used as a natural laboratory to perform these studies.
Intellectual Merit. The data generated in this study will allow constraints on the relationship between autotrophic carbon fixation and the resulting isotopic signatures of biomass and specific biomarker molecules (e.g. CH4, C2+ alkanes, lipids) in a natural system. This has implications for assessing the importance of carbon fixation in extant ecosystems, and it will also provide a tool to improve the interpretation of isotopic values in the geological record.
| Name | Affiliation | Role |
|---|---|---|
| Costantino Vetriani | Rutgers University | Co-Principal Investigator |
| Stefan M. Sievert | Woods Hole Oceanographic Institution (WHOI) | Co-Principal Investigator |
| Dionysis I. Foustoukos | Carnegie Institution for Science (CIS) | Co-Principal Investigator |
| URL | https://www.bco-dmo.org/dataset/628993 |
|---|---|
| Download URL | https://www.bco-dmo.org/dataset/628993/data/download |
| Media Type | text/tab-separated-values |
| Created | December 16, 2015 |
| Modified | February 13, 2017 |
| State | Final no updates expected |
| Brief Description | Results of on-board incubations of microbes in diffuse flow vent fluids collected from Crab Spa and Alvinella patch |
From AT26-10 cruise report (01/29/2014):
DOB: An Integrated Study of Energy Metabolism, Carbon Fixation, and Colonization Mechanisms in Chemosynthetic Microbial Communities at Deep-Sea Vents
Cruise Report by the CIW research team: Dr. Ileana Perez-Rodriguez, Mr. Matt Rawls and Dr. Dionysis I. Foustoukos
The CIW team was responsible for the shipboard continuous culturing incubations of vent fluids collected from Crab Spa and Tica hot springs during the AT26-10 expedition at 9oN EPR by utilizing our high-pressure bioreactor (Fig. 1). This was accomplished through a collaborative effort with Jeff Seewald and Sean Sylva (WHOI), who deployed isobaric gas-tight samplers (IGTs) to collect hydrothermal vent fluids at the diffuse flow sites. Experiments were designed to study the cycling to N through the metabolic processes of denitrification and dissimilatory nitrate reduction to ammonia (DNRA) under in-situ deep-sea vent temperature and pressure conditions.
We studied the evolution of nitrate reducing microorganisms at mesophilic (30oC) and thermophilic (50oC) conditions at pressures ranging from 5 to 250 bar. Vent fluids (16 IGTs) were delivered in the bioreactor and homogeneously mixed with aqueous media solution enriched in dissolved nitrate, hydrogen and 13C labeled bicarbonate to facilitate the growth of nitrate reducing microorganisms (Fig. 2). The two distinct sets of experiments were lasted for 356 and 100 hours. In short, experimental results constrained the function and metabolic rates of the denitrifying microbial communities in the Crab Spa fluids, while DNRA metabolic pathways were identified for the populations residing in the moderate temperature vent fluids (60oC) of the Alvinella colony at Tica.
During the course of the experiments we monitored the growth of deep-sea microbial communities by measuring the concentrations of dissolved aqueous species directly involved in nitrate based metabolism, such as NO3, NH4, H2 and H2S. We also monitored cell densities by utilizing an epi-fluorescence microscope (Sievert, WHOI). Dissolved gas and NH4+ concentrations were attained by gas and ion chromatography (Seewald – Sylva, WHOI). Subsamples were also collected for a number of offshore analysis to determine: i) the 15N/14N isotope composition of NO3-,/NH4+ and constrain kinetic isotope effects associated with denitrification/DNRA (Perez-Rodriguez, CIW), ii) to study the rates of autotrophic carbon fixation by NanoSIMS (Musat, UFZ), iii) to perform single cell genomics on the microbial populations grown in the bioreactor (Ramunas, Bigelow) and (iv) to isolate and characterize novel microogranisms from the communities cultured in our experiments (Perez-Rodriguez, CIW and Vetriani, Rutgers).
BCO-DMO Processing:
Isobaric Gas Tight (IGT) samplers, designed and built by scientists and engineers at WHOI, are titanium instruments designed to be used with deep submergence vehicles to sample corrosive hydrothermal vent fluids at high temperature and high pressure. The IGT prevents the sampled fluid from degassing as pressure decreases during the vehicle’s ascent to the surface.
The integrated system allows for the culturing of microorganisms under hydrostatic pressures from 0.1 to 69 MPa (and up to 138 MPa with ongoing developments) and at temperatures ranging from 25 to 120°C. For full description, see Foustoukos and Perez-Rodriguez (2015), Applied and Environmental Microbiology, 81, 6850
A device mounted on a ship that holds water samples under conditions of controlled temperature or controlled temperature and illumination.
Olympus BX61 microscope with a UPlanF1 100x (numerical aperture, 1.3) oil immersion objective
Instruments that generate enlarged images of samples using the phenomena of reflection and absorption of visible light. Includes conventional and inverted instruments. Also called a "light microscope".
JSM-6500F field emission scanning electron microscope (JEOL)
Instruments that generate enlarged images of samples using the phenomena of reflection and absorption of electrons behaving as waves.
start date of incubation in yyyy-mm-dd format
date sampling starts such as YYYYMMDD
end date of incubation in yyyy-mm-dd format
water pressure at measurement; depth reported as pressure; positive number increasing with water depth
ammonium concentration
Ammonium and ammonia concentration parameters in any body of fresh or salt water.
hydrogen concentration
methane concentration
cell_concentration
Concentration of cells; often determined by spectrophotometry, flow cytometry, or using a microscope.
d15N_NO3_ppt
delta 15N (d15N) is a measure of the ratio of stable isotopes 15N:14N. It is commonly reported in parts per thousand (per mil, 0/00).
| Name | Affiliation | Contact |
|---|---|---|
| Dionysis I. Foustoukos | Carnegie Institution for Science (CIS) | ✓ |
| Nancy Copley | Carnegie Institution for Science (CIS) | ✓ |
| Project Title | An Integrated Study of Energy Metabolism, Carbon Fixation, and Colonization Mechanisms in Chemosynthetic Microbial Communities at Deep-Sea Vents |
|---|---|
| Acronym | Microbial Communities at Deep-Sea Vents |
| URL | https://www.bco-dmo.org/project/2216 |
| Created | June 11, 2012 |
| Modified | June 11, 2012 |
Deep-sea hydrothermal vents, first discovered in 1977, are poster child ecosystems where microbial chemosynthesis rather than photosynthesis is the primary source of organic carbon. Significant gaps remain in our understanding of the underlying microbiology and biogeochemistry of these fascinating ecosystems. Missing are the identification of specific microorganisms mediating critical reactions in various geothermal systems, metabolic pathways used by the microbes, rates of the catalyzed reactions, amounts of organic carbon being produced, and the larger role of these ecosystems in global biogeochemical cycles. To fill these gaps, the investigators will conduct a 3-year interdisciplinary, international hypothesis-driven research program to understand microbial processes and their quantitative importance at deep-sea vents. Specifically, the investigators will address the following objectives: 1. Determine key relationships between the taxonomic, genetic and functional diversity, as well as the mechanisms of energy and carbon transfer, in deep-sea hydrothermal vent microbial communities. 2. Identify the predominant metabolic pathways and thus the main energy sources driving chemoautotrophic production in high and low temperature diffuse flow vents. 3. Determine energy conservation efficiency and rates of aerobic and anaerobic chemosynthetic primary productivity in high and low temperature diffuse flow vents. 4. Determine gene expression patterns in diffuse-flow vent microbial communities during attachment to substrates and the development of biofilms.
Integration: To address these objectives and to characterize the complexity of microbially-catalyzed processes at deep-sea vents at a qualitatively new level, we will pursue an integrated approach that couples an assessment of taxonomic diversity using cultivation-dependent and -independent approaches with methodologies that address genetic diversity, including a) metagenomics (genetic potential and diversity of community), b) single cell genomics (genetic potential and diversity of uncultured single cells), c) meta-transcriptomics and -proteomics (identification and function of active community members, realized potential of the community). To assess function and response to the environment, these approaches will be combined with 1) measurement of in situ rates of chemoautotrophic production, 2) geochemical characterization of microbial habitats, and 3) shipboard incubations under simulated in situ conditions (hypothesis testing under controlled physicochemical conditions). Network approaches and mathematical simulation will be used to reconstruct the metabolic network of the natural communities. A 3-day long project meeting towards the end of the second year will take place in Woods Hole. This Data Integration and Synthesis meeting will allow for progress reports and presentations from each PI, postdoc, and/or student, with the aim of synthesizing data generated to facilitate the preparation of manuscripts.
Intellectual Merit. Combining the community expression profile with diversity and metagenomic analyses as well as process and habitat characterization will be unique to hydrothermal vent microbiology. The approach will provide new insights into the functioning of deep-sea vent microbial communities and the constraints regulating the interactions between the microbes and their abiotic and biotic environment, ultimately enabling us to put these systems into a quantitative framework and thus a larger global context.
Broader Impacts. This is an interdisciplinary and collaborative effort between 4 US and 4 foreign institutions, creating unique opportunities for networking and fostering international collaborations. This will also benefit the involved students (2 graduate, several undergraduate) and 2 postdoctoral associates. This project will directly contribute to many educational and public outreach activities of the involved PIs, including the WHOI Dive & Discover program; single cell genomics workshops and Cafe Scientifique (Bigelow); REU (WHOI, Bigelow, CIW); COSEE and RIOS (Rutgers), and others. The proposed research fits with the focus of a number of multidisciplinary and international initiatives, in which PIs are active members (SCOR working group on Hydrothermal energy and the ocean carbon cycle, http://www.scorint. org/Working_Groups/wg135.htm; Deep Carbon Observatory at CIW, https://dco.gl.ciw.edu/; Global Biogeochemical Flux (GBF) component of the Ocean Observatories Initiative (OOI), http://www.whoi.edu/GBF-OOI/page.do?pid=41475)
| Name | Affiliation | Role |
|---|---|---|
| Stefan M. Sievert | Woods Hole Oceanographic Institution (WHOI) | Lead Principal Investigator |
| Costantino Vetriani | Rutgers University | Principal Investigator |
| Dionysis I. Foustoukos | Carnegie Institution for Science (CIS) | Principal Investigator |
| Ramunas Stepanauskas | Bigelow Laboratory for Ocean Sciences | Principal Investigator |
| Craig Taylor | Woods Hole Oceanographic Institution (WHOI) | Co-Principal Investigator |
| Jeffrey S. Seewald | Max Planck Institute for Marine Microbiology (MPI) | International Collaborator |
| Nadine Le Bris | University of Greifswald | International Collaborator |
| Niculina Musat | Shanghai Jiao Tong University (SJTU) | International Collaborator |
| Thomas Schweder | Laboratoire d'Écogéochimie des Environnements Benthiques (LECOB) | International Collaborator |
| Fengping Wang | Woods Hole Oceanographic Institution (WHOI) | Co-Principal Investigator |
| URL | https://www.bco-dmo.org/dataset/529026 |
|---|---|
| Download URL | https://www.bco-dmo.org/dataset/529026/data/download |
| Media Type | text/tab-separated-values |
| Created | September 30, 2014 |
| Modified | February 13, 2017 |
| State | Final no updates expected |
| Brief Description | Chemical composition of diffuse flow vent fluids collected from Crab Spa, 9N on the East Pacific Rise |
These samples were collected with Isobaric-Gas-Tight samplers and processed onboard R/V Atlantis. The IGT samplers were deployed by Dr. Jeff Seewald from WHOI. Chemical analysis of the major cation/anion species was conducted at the Geophysical Lab, Carnegie Institution of Washington
BCO-DMO Processing:
Metrohm/Dionex, for cation and anion species.
Ion chromatography is a form of liquid chromatography that measures concentrations of ionic species by separating them based on their interaction with a resin. Ionic species separate differently depending on species type and size. Ion chromatographs are able to measure concentrations of major anions, such as fluoride, chloride, nitrate, nitrite, and sulfate, as well as major cations such as lithium, sodium, ammonium, potassium, calcium, and magnesium in the parts-per-billion (ppb) range. (from http://serc.carleton.edu/microbelife/research_methods/biogeochemical/ic.html)
Isobaric Gas Tight (IGT) samplers, designed and built by scientists and engineers at WHOI, are titanium instruments designed to be used with deep submergence vehicles to sample corrosive hydrothermal vent fluids at high temperature and high pressure. The IGT prevents the sampled fluid from degassing as pressure decreases during the vehicle’s ascent to the surface.
sampling date. Format: YYYY-MM-DD
date; generally reported in GMT as YYYYMMDD (year; month; day); also as MMDD (month; day); EqPac dates are local Hawaii time. ISO_Date format is YYYY-MM-DD (http://www.iso.org/iso/home/standards/iso8601.htm)
latitude, in decimal degrees, North is positive, negative denotes South; Reported in some datasets as degrees, minutes
longitude, in decimal degrees, East is positive, negative denotes West; Reported in some datsets as degrees, minutes
unique sample identification or number; any combination of alpha numeric characters; precise definition is file dependent
Sodium (Na). Concentrations may be reported in parts per million, nanomoles per liter, or other units. Refer to dataset metadata for units.
K (potassium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Mg (magnesium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Calcium (Ca). Concentrations may be reported in parts per million, nanomoles per liter, or other units. Refer to dataset metadata for units.
depth where sample was taken
Observation/sample depth below the sea surface. Units often reported as: meters, feet.
When used in a JGOFS/GLOBEC dataset the depth is a best estimate; usually but not always calculated from pressure; calculated either from CTD pressure using Fofonoff and Millard (1982; UNESCO Tech Paper #44) algorithm adjusted for 1980 equation of state for seawater (EOS80) or simply equivalent to nominal depth as recorded during sampling if CTD pressure was unavailable.
| Name | Affiliation | Contact |
|---|---|---|
| Dionysis I. Foustoukos | Carnegie Institution for Science (CIS) | ✓ |
| Nancy Copley | Carnegie Institution for Science (CIS) | ✓ |
| Project Title | An Integrated Study of Energy Metabolism, Carbon Fixation, and Colonization Mechanisms in Chemosynthetic Microbial Communities at Deep-Sea Vents |
|---|---|
| Acronym | Microbial Communities at Deep-Sea Vents |
| URL | https://www.bco-dmo.org/project/2216 |
| Created | June 11, 2012 |
| Modified | June 11, 2012 |
Deep-sea hydrothermal vents, first discovered in 1977, are poster child ecosystems where microbial chemosynthesis rather than photosynthesis is the primary source of organic carbon. Significant gaps remain in our understanding of the underlying microbiology and biogeochemistry of these fascinating ecosystems. Missing are the identification of specific microorganisms mediating critical reactions in various geothermal systems, metabolic pathways used by the microbes, rates of the catalyzed reactions, amounts of organic carbon being produced, and the larger role of these ecosystems in global biogeochemical cycles. To fill these gaps, the investigators will conduct a 3-year interdisciplinary, international hypothesis-driven research program to understand microbial processes and their quantitative importance at deep-sea vents. Specifically, the investigators will address the following objectives: 1. Determine key relationships between the taxonomic, genetic and functional diversity, as well as the mechanisms of energy and carbon transfer, in deep-sea hydrothermal vent microbial communities. 2. Identify the predominant metabolic pathways and thus the main energy sources driving chemoautotrophic production in high and low temperature diffuse flow vents. 3. Determine energy conservation efficiency and rates of aerobic and anaerobic chemosynthetic primary productivity in high and low temperature diffuse flow vents. 4. Determine gene expression patterns in diffuse-flow vent microbial communities during attachment to substrates and the development of biofilms.
Integration: To address these objectives and to characterize the complexity of microbially-catalyzed processes at deep-sea vents at a qualitatively new level, we will pursue an integrated approach that couples an assessment of taxonomic diversity using cultivation-dependent and -independent approaches with methodologies that address genetic diversity, including a) metagenomics (genetic potential and diversity of community), b) single cell genomics (genetic potential and diversity of uncultured single cells), c) meta-transcriptomics and -proteomics (identification and function of active community members, realized potential of the community). To assess function and response to the environment, these approaches will be combined with 1) measurement of in situ rates of chemoautotrophic production, 2) geochemical characterization of microbial habitats, and 3) shipboard incubations under simulated in situ conditions (hypothesis testing under controlled physicochemical conditions). Network approaches and mathematical simulation will be used to reconstruct the metabolic network of the natural communities. A 3-day long project meeting towards the end of the second year will take place in Woods Hole. This Data Integration and Synthesis meeting will allow for progress reports and presentations from each PI, postdoc, and/or student, with the aim of synthesizing data generated to facilitate the preparation of manuscripts.
Intellectual Merit. Combining the community expression profile with diversity and metagenomic analyses as well as process and habitat characterization will be unique to hydrothermal vent microbiology. The approach will provide new insights into the functioning of deep-sea vent microbial communities and the constraints regulating the interactions between the microbes and their abiotic and biotic environment, ultimately enabling us to put these systems into a quantitative framework and thus a larger global context.
Broader Impacts. This is an interdisciplinary and collaborative effort between 4 US and 4 foreign institutions, creating unique opportunities for networking and fostering international collaborations. This will also benefit the involved students (2 graduate, several undergraduate) and 2 postdoctoral associates. This project will directly contribute to many educational and public outreach activities of the involved PIs, including the WHOI Dive & Discover program; single cell genomics workshops and Cafe Scientifique (Bigelow); REU (WHOI, Bigelow, CIW); COSEE and RIOS (Rutgers), and others. The proposed research fits with the focus of a number of multidisciplinary and international initiatives, in which PIs are active members (SCOR working group on Hydrothermal energy and the ocean carbon cycle, http://www.scorint. org/Working_Groups/wg135.htm; Deep Carbon Observatory at CIW, https://dco.gl.ciw.edu/; Global Biogeochemical Flux (GBF) component of the Ocean Observatories Initiative (OOI), http://www.whoi.edu/GBF-OOI/page.do?pid=41475)
| Name | Affiliation | Role |
|---|---|---|
| Stefan M. Sievert | Woods Hole Oceanographic Institution (WHOI) | Lead Principal Investigator |
| Costantino Vetriani | Rutgers University | Principal Investigator |
| Dionysis I. Foustoukos | Carnegie Institution for Science (CIS) | Principal Investigator |
| Ramunas Stepanauskas | Bigelow Laboratory for Ocean Sciences | Principal Investigator |
| Craig Taylor | Woods Hole Oceanographic Institution (WHOI) | Co-Principal Investigator |
| Jeffrey S. Seewald | Max Planck Institute for Marine Microbiology (MPI) | International Collaborator |
| Nadine Le Bris | University of Greifswald | International Collaborator |
| Niculina Musat | Shanghai Jiao Tong University (SJTU) | International Collaborator |
| Thomas Schweder | Laboratoire d'Écogéochimie des Environnements Benthiques (LECOB) | International Collaborator |
| Fengping Wang | Woods Hole Oceanographic Institution (WHOI) | Co-Principal Investigator |
| Project Title | Autotrophic carbon fixation at a shallow-water hydrothermal system: Constraining microbial activity, isotopic and geochemical regimes |
|---|---|
| Acronym | Hydrothermal Autotrophic Carbon Fixation |
| URL | https://www.bco-dmo.org/project/473892 |
| Created | January 8, 2014 |
| Modified | June 3, 2015 |
In this project we studied the shallow-water hydrothermal vent sites at Milos Island (Greece) to better understand the extent of autotrophic carbon fixation and its chemical and isotopic signature along environmental (redox/thermal) gradients. This was a 12-day long expedition (May 18 to 30, 2012) to sample vent fluids, gases and retrieve sediment cores at Paleochori Bay by using SCUBA diving at 8-10 m depth. In addition to the submarine vent sites, two subaerial locations of venting were identified at 36o 40′ 28″N – 24o 31′ 14″ E and 36o 40′ 25″ N – 24o 30′ 44″ E. Both the subaerial and submarine sites are located on the same fracture zone that likely controls the hydrothermal circulation of evolved meteoritic water and seawater within the magmatic zone of Milos Island. To this end, the geochemistry of the fluids and gases emitted from subaerial sites provide important information towards identifying the linkage between the subaerial and submarine magmatic activity and provide insights on the metabolic functions (e.g. H2 oxidation, Fe(III) reduction, C and S cycling) of the subsurface microbial community.
Abstract:
Currently, there is only limited information on the identity and activity of the microorganisms carrying out CO2-fixation in situ, despite the fact that these organisms form the basis of their respective ecosystems. Representatives that are able to grow autotrophically are known to exist in almost all major groups of prokaryotes, and these organisms play essential roles in ecosystems by providing a continuous supply of organic carbon for heterotrophs. Microorganisms present in extreme environments utilize CO2- fixation pathways other than the Calvin-Benson-Bassham (CBB) cycle. At present, five alternative autotrophic CO2 fixation pathways are known. Different carbon fixation pathways result in distinct isotopic signatures of the produced biomass due to the isotopic discrimination between light (12C) and heavy (13C) carbon by the carboxylating enzymes. Thus, inferences about the carbon fixation pathway predominantly utilized by the microbial community can also be made based on the stable carbon isotopic composition of the organic matter, in extant systems as well as in the geological record. However, at present little is known about the systematics and extents of fractionation during carbon fixation by prokaryotic organisms, and to our knowledge no studies exist that have systematically studied the relationship between the operation of different carbon fixation pathways and how this is reflected in the stable carbon isotopic composition in a natural system. This is a 2-year interdisciplinary, international research program that employs a powerful combination of cutting-edge research tools aiming to improve our understanding of autotrophic carbon fixation and its chemical and isotopic signature along environmental gradients in a natural hydrothermal system. The following hypotheses are addressed:
1. The diversity of microorganisms present along a thermal and redox gradient, and rates of CO2 fixation, will reflect adaptation to in situ temperatures and geochemical conditions
2. Microorganisms utilizing the CBB cycle for autotrophic CO2-fixation will represent a smaller percentage of the chemolithoautotrophic community at higher temperatures, where microorganisms utilizing alternative CO2-fixation pathways dominate
3. Isotopic values of biomass and specific biomarker molecules will vary along a thermal and redox gradient from zones characterized by a higher hydrothermal fluid flux and thus higher temperatures to the surrounding, cooler areas, corresponding to the physiology of the microorganisms utilizing different pathways for carbon fixation
The PIs will use a multidisciplinary approach to delineate the relative contribution of the different carbon fixation pathways along an environmental gradient by combining metagenomic analyses coupled with: 1) an assessment of the frequency and the expression of specific key genes involved in carbon fixation, and 2) with the measurement of carbon fixation rates. These data will be integrated with the determination of stable C isotopic composition of biomass, DIC, and specific hydrocarbons/lipids. Due to its easy accessibility, well-established environmental gradients, and extensive background information, the shallow-water vents off Milos (Greece) will be used as a natural laboratory to perform these studies.
Intellectual Merit. The data generated in this study will allow constraints on the relationship between autotrophic carbon fixation and the resulting isotopic signatures of biomass and specific biomarker molecules (e.g. CH4, C2+ alkanes, lipids) in a natural system. This has implications for assessing the importance of carbon fixation in extant ecosystems, and it will also provide a tool to improve the interpretation of isotopic values in the geological record.
| Name | Affiliation | Role |
|---|---|---|
| Costantino Vetriani | Rutgers University | Co-Principal Investigator |
| Stefan M. Sievert | Woods Hole Oceanographic Institution (WHOI) | Co-Principal Investigator |
| Dionysis I. Foustoukos | Carnegie Institution for Science (CIS) | Co-Principal Investigator |
| Project Title | An Integrated Study of Energy Metabolism, Carbon Fixation, and Colonization Mechanisms in Chemosynthetic Microbial Communities at Deep-Sea Vents |
|---|---|
| Acronym | Microbial Communities at Deep-Sea Vents |
| URL | https://www.bco-dmo.org/project/2216 |
| Created | June 11, 2012 |
| Modified | June 11, 2012 |
Deep-sea hydrothermal vents, first discovered in 1977, are poster child ecosystems where microbial chemosynthesis rather than photosynthesis is the primary source of organic carbon. Significant gaps remain in our understanding of the underlying microbiology and biogeochemistry of these fascinating ecosystems. Missing are the identification of specific microorganisms mediating critical reactions in various geothermal systems, metabolic pathways used by the microbes, rates of the catalyzed reactions, amounts of organic carbon being produced, and the larger role of these ecosystems in global biogeochemical cycles. To fill these gaps, the investigators will conduct a 3-year interdisciplinary, international hypothesis-driven research program to understand microbial processes and their quantitative importance at deep-sea vents. Specifically, the investigators will address the following objectives: 1. Determine key relationships between the taxonomic, genetic and functional diversity, as well as the mechanisms of energy and carbon transfer, in deep-sea hydrothermal vent microbial communities. 2. Identify the predominant metabolic pathways and thus the main energy sources driving chemoautotrophic production in high and low temperature diffuse flow vents. 3. Determine energy conservation efficiency and rates of aerobic and anaerobic chemosynthetic primary productivity in high and low temperature diffuse flow vents. 4. Determine gene expression patterns in diffuse-flow vent microbial communities during attachment to substrates and the development of biofilms.
Integration: To address these objectives and to characterize the complexity of microbially-catalyzed processes at deep-sea vents at a qualitatively new level, we will pursue an integrated approach that couples an assessment of taxonomic diversity using cultivation-dependent and -independent approaches with methodologies that address genetic diversity, including a) metagenomics (genetic potential and diversity of community), b) single cell genomics (genetic potential and diversity of uncultured single cells), c) meta-transcriptomics and -proteomics (identification and function of active community members, realized potential of the community). To assess function and response to the environment, these approaches will be combined with 1) measurement of in situ rates of chemoautotrophic production, 2) geochemical characterization of microbial habitats, and 3) shipboard incubations under simulated in situ conditions (hypothesis testing under controlled physicochemical conditions). Network approaches and mathematical simulation will be used to reconstruct the metabolic network of the natural communities. A 3-day long project meeting towards the end of the second year will take place in Woods Hole. This Data Integration and Synthesis meeting will allow for progress reports and presentations from each PI, postdoc, and/or student, with the aim of synthesizing data generated to facilitate the preparation of manuscripts.
Intellectual Merit. Combining the community expression profile with diversity and metagenomic analyses as well as process and habitat characterization will be unique to hydrothermal vent microbiology. The approach will provide new insights into the functioning of deep-sea vent microbial communities and the constraints regulating the interactions between the microbes and their abiotic and biotic environment, ultimately enabling us to put these systems into a quantitative framework and thus a larger global context.
Broader Impacts. This is an interdisciplinary and collaborative effort between 4 US and 4 foreign institutions, creating unique opportunities for networking and fostering international collaborations. This will also benefit the involved students (2 graduate, several undergraduate) and 2 postdoctoral associates. This project will directly contribute to many educational and public outreach activities of the involved PIs, including the WHOI Dive & Discover program; single cell genomics workshops and Cafe Scientifique (Bigelow); REU (WHOI, Bigelow, CIW); COSEE and RIOS (Rutgers), and others. The proposed research fits with the focus of a number of multidisciplinary and international initiatives, in which PIs are active members (SCOR working group on Hydrothermal energy and the ocean carbon cycle, http://www.scorint. org/Working_Groups/wg135.htm; Deep Carbon Observatory at CIW, https://dco.gl.ciw.edu/; Global Biogeochemical Flux (GBF) component of the Ocean Observatories Initiative (OOI), http://www.whoi.edu/GBF-OOI/page.do?pid=41475)
| Name | Affiliation | Role |
|---|---|---|
| Stefan M. Sievert | Woods Hole Oceanographic Institution (WHOI) | Lead Principal Investigator |
| Costantino Vetriani | Rutgers University | Principal Investigator |
| Dionysis I. Foustoukos | Carnegie Institution for Science (CIS) | Principal Investigator |
| Ramunas Stepanauskas | Bigelow Laboratory for Ocean Sciences | Principal Investigator |
| Craig Taylor | Woods Hole Oceanographic Institution (WHOI) | Co-Principal Investigator |
| Jeffrey S. Seewald | Max Planck Institute for Marine Microbiology (MPI) | International Collaborator |
| Nadine Le Bris | University of Greifswald | International Collaborator |
| Niculina Musat | Shanghai Jiao Tong University (SJTU) | International Collaborator |
| Thomas Schweder | Laboratoire d'Écogéochimie des Environnements Benthiques (LECOB) | International Collaborator |
| Fengping Wang | Woods Hole Oceanographic Institution (WHOI) | Co-Principal Investigator |
A novel thermophilic, anaerobic, mixotrophic bacterium, designated strain MAG-PB1T, was isolated from a shallow-water hydrothermal vent system in Palaeochori Bay off the coast of the island of Milos, Greece. The cells were Gram-negative, rugose, short rods, approximately 1.0 μm long and 0.5 μm wide. Strain MAG-PB1T grew at 30–70 °C (optimum 60 °C), 0–50 g NaCl l− 1 (optimum 15–20 g l− 1) and pH 5.5–8.0 (optimum pH 6.0). Generation time under optimal conditions was 2.5 h. Optimal growth occurred under chemolithoautotrophic conditions with H2 as the energy source and CO2 as the carbon source. Fe(III), Mn(IV), arsenate and selenate were used as electron acceptors. Peptone, tryptone, Casamino acids, sucrose, yeast extract, d-fructose, α-d-glucose and ( − )-d-arabinose also served as electron donors. No growth occurred in the presence of lactate or formate. The G+C content of the genomic DNA was 66.7 mol%. Phylogenetic analysis of the 16S rRNA gene sequence indicated that this organism is closely related to Deferrisoma camini, the first species of a recently described genus in the Deltaproteobacteria. Based on the 16S rRNA gene phylogenetic analysis and on physiological, biochemical and structural characteristics, the strain was found to represent a novel species, for which the name Deferrisoma palaeochoriense sp. nov. is proposed. The type strain is MAG-PB1T ( = JCM 30394T = DSM 29363T).
Continuous culture under elevated pressures is an important technique for expanding the exploration of microbial growth and survival in extreme environments associated with the deep biosphere. Here we present a benchtop stirred continuous culture bioreactor capable of withstanding temperatures ranging from 25 to 120°C and pressures as high as 69 MPa. The system is configured to allow the employment of media enriched in dissolved gases, under oxic or anoxic conditions, while permitting periodic sampling of the incubated organisms with minimal physical/chemical disturbance inside the reactor. In a pilot experiment, the fermentative growth of the thermopiezophilic bacterium Marinitoga piezophila was investigated continuously for 382 h at 65°C and at pressures ranging from 0.1 to 40 MPa while the medium flow rate was varied from 2 to 0.025 ml/min. The enhanced growth observed at 30 and 40 MPa and 0.025 ml/min supports the pressure preferences of M. piezophila when grown fermentatively. This assay successfully demonstrates the capabilities of the bioreactor for continuous culturing at a variety of dilution rates, pressures, and temperatures. We anticipate that this technology will accelerate our understanding of the physiological and metabolic status of microorganisms under temperature, pressure, and energy regimes resembling those of the Earth’s piezosphere.
The optimization of microbial metabolism has been described as the result of the balance between efficiency, or biomass yields, during anabolism and the kinetics of energy yielding reactions, or respiration rates, during catabolism. Through my C-DEBI postdoctoral research I have obtained experimental data that will help us understand how environmental factors relevant to deep-sea hydrothermal systems affect the trade-offs between efficiency and kinetics in deep-sea vent metabolisms. Particularly, I have been studying the metabolic trade-offs during chemosynthetic NO3- reduction, as well as its associated stable N isotope signatures, in endemic vent ε-Proteobacteria and Aquificae under different temperature regimes. We found, through culture-based approaches, that these bioenergetic traits were generally conserved between these two groups along with their physiologies, with no substantive overall differences in their N isotope effects. Further laboratory culturing of representative members of each group (Caminibacter mediatlanticus and Thermovibrio ammonificans) under seafloor pressures (20MPa) showed that N isotope effects were independent of pressure effects, while growth rates and NO3- reduction kinetic rate constants were significantly decreased under increased pressures. Currently, we are complementing our pure culture research with new studies using natural vent microbial communities to further constrain the role of NO3- reduction at in-situ seafloor temperatures and pressures. Additionally, I worked towards the isolation and characterization of a novel Fe(III) reducing microorganism, Deferrisoma paleochorii, in order to start research activities in the bioenergetics of Fe-based metabolisms. The goal is to increase our understanding of the relationship between bioenergetic landscapes, biogeography and biogeochemistry in these seafloor regions.
