scholarly journals Discriminative biogeochemical signatures of methanotrophs in different chemosynthetic habitats at an active mud volcano in the Canadian Beaufort Sea

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Dong-Hun Lee ◽  
Yung Mi Lee ◽  
Jung-Hyun Kim ◽  
Young Keun Jin ◽  
Charles Paull ◽  
...  
Keyword(s):  
Methane Oxidation ◽  
Microbial Mats ◽  
Methane Flux ◽  
Beaufort Sea ◽  
Mud Volcano ◽  
Remotely Operated Vehicle ◽  
Geochemical Properties ◽  
Lipid Biomarker ◽  
Methyl Sterols ◽  
Methanotrophic Communities

AbstractSeveral mud volcanoes are active in the Canadian Beaufort Sea. In this study, we investigated vertical variations in methanotrophic communities in sediments of the mud volcano MV420 (420 m water depth) by analyzing geochemical properties, microbial lipids, and nucleic acid signatures. Three push cores were collected with a remotely operated vehicle from visually discriminative habitats that were devoid of megafauna and/microbial mats (DM) to the naked eye, covered with bacterial mats (BM), or colonized by siboglinid tubeworms (ST). All MV420 sites showed the presence of aerobic methane oxidation (MOx)- and anaerobic methane oxidation (AOM)-related lipid biomarkers (4α-methyl sterols and sn-2-hydroxyarchaeol, respectively), which were distinctly different in comparison with a reference site at which these compounds were not detected. Lipid biomarker results were in close agreement with 16S rRNA analyses, which revealed the presence of MOx-related bacteria (Methylococcales) and AOM-related archaea (ANME-2 and ANME-3) at the MV420 sites. 4α-methyl sterols derived from Methylococcales predominated in the surface layer at the BM site, which showed a moderate methane flux (0.04 mmol cm−2 y−1), while their occurrence was limited at the DM (0.06 mmol cm−2 y−1) and ST (0.01 mmol cm−2 y−1) sites. On the other hand, 13C-depleted sn-2-hydroxyarchaeol potentially derived from ANME-2 and/or ANME-3 was abundant in down-core sediments at the ST site. Our study indicates that a niche diversification within this mud volcano system has shaped distinct methanotrophic communities due to availability of electron acceptors in association with varying degrees of methane flux and bioirrigation activity.

scholarly journals Geochemical and Microbial Signatures of Siboglinid Tubeworm Habitats at an Active Mud Volcano in the Canadian Beaufort Sea

2021 ◽  
Vol 8 ◽  
Author(s):  
Dong-Hun Lee ◽  
Jung-Hyun Kim ◽  
Yung Mi Lee ◽  
Ji-Hoon Kim ◽  
Young Keun Jin ◽  
...  
Keyword(s):  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Methane Flux ◽  
Beaufort Sea ◽  
Lipid Biomarkers ◽  
Mud Volcano ◽  
Anaerobic Oxidation Of Methane ◽  
Community Characteristics ◽  
Oxidation Of Methane ◽  
Geochemical Properties

During the ARA08C expedition in 2017, sediment push cores were collected at an active mud volcano (420 m water depth) in the Canadian Beaufort Sea from two visually discriminative siboglinid tubeworm (ST) habitats that were colonized densely and less densely (ST1 and ST2, respectively). In this study, we investigated the biogeochemical and microbial community characteristics at ST1 by analyzing the geochemical properties, microbial lipids, and nucleic acid signatures, and comparing them with the data previously reported from ST2. The two ST sites showed distinct differences in vertical geochemical gradients [methane, sulfate, dissolved inorganic carbon (DIC), total organic carbon, and total sulfur], with a higher methane flux recorded at ST1 (0.05 mmol cm–2 y–1) than at ST2 (0.01 mmol cm–2 y–1). Notably, the δ13C values of DIC were more depleted at ST1 than at ST2, resulting in a higher proportion of DIC derived from the anaerobic oxidation of methane (AOM) at ST1 than at ST2. Moreover, both the ST1 and ST2 sites revealed the dominance of AOM-related lipid biomarkers (especially sn-2-hydroxyarchaeol), showing highly 13C-depleted values. The 16S rRNA analyses showed the presence of AOM-related archaea, predominantly anaerobic methanotrophic archaea (ANME)-3 at ST1 and ST2. Our results suggest that AOM-related byproducts (sulfide and DIC) potentially derived from ANME-3 were more abundant at ST1 than at ST2. This variation was attributed to the intensity and persistence of ascending methane. Therefore, our study suggests that AOM-derived byproducts are possibly an essential energy source for tubeworms during chemosynthetic metabolism, shaping different colony types on the seafloor.

scholarly journals Biogeochemistry and Community Composition of Iron- and Sulfur-Precipitating Microbial Mats at the Chefren Mud Volcano (Nile Deep Sea Fan, Eastern Mediterranean)

2008 ◽  
Vol 74 (10) ◽  
pp. 3198-3215 ◽  
Author(s):  
Enoma O. Omoregie ◽  
Vincent Mastalerz ◽  
Gert de Lange ◽  
Kristina L. Straub ◽  
Andreas Kappler ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Microbial Mats ◽  
Eastern Mediterranean ◽  
Sulfide Oxidation ◽  
Mud Volcano ◽  
Rrna Gene ◽  
Anaerobic Oxidation Of Methane ◽  
Gene Sequences ◽  
16S Rrna Gene Sequences

ABSTRACT In this study we determined the composition and biogeochemistry of novel, brightly colored, white and orange microbial mats at the surface of a brine seep at the outer rim of the Chefren mud volcano. These mats were interspersed with one another, but their underlying sediment biogeochemistries differed considerably. Microscopy revealed that the white mats were granules composed of elemental S filaments, similar to those produced by the sulfide-oxidizing epsilonproteobacterium “Candidatus Arcobacter sulfidicus.” Fluorescence in situ hybridization indicated that microorganisms targeted by a “Ca. Arcobacter sulfidicus”-specific oligonucleotide probe constituted up to 24% of the total the cells within these mats. Several 16S rRNA gene sequences from organisms closely related to “Ca. Arcobacter sulfidicus” were identified. In contrast, the orange mat consisted mostly of bright orange flakes composed of empty Fe(III) (hydr)oxide-coated microbial sheaths, similar to those produced by the neutrophilic Fe(II)-oxidizing betaproteobacterium Leptothrix ochracea. None of the 16S rRNA gene sequences obtained from these samples were closely related to sequences of known neutrophilic aerobic Fe(II)-oxidizing bacteria. The sediments below both types of mats showed relatively high sulfate reduction rates (300 nmol·cm−3·day−1) partially fueled by the anaerobic oxidation of methane (10 to 20 nmol·cm−3·day−1). Free sulfide produced below the white mat was depleted by sulfide oxidation within the mat itself. Below the orange mat free Fe(II) reached the surface layer and was depleted in part by microbial Fe(II) oxidation. Both mats and the sediments underneath them hosted very diverse microbial communities and contained mineral precipitates, most likely due to differences in fluid flow patterns.

Physiological status and microbial diversity assessment of microbial mats: The signature lipid biomarker approach

Ophelia ◽  
2004 ◽  
Vol 58 (3) ◽  
pp. 165-173 ◽  
Author(s):  
Laura Villanueva ◽  
Antoni Navarrete ◽  
Jordi Urmeneta ◽  
David C. White ◽  
Ricardo Guerrero
Keyword(s):  
Microbial Diversity ◽  
Microbial Mats ◽  
Physiological Status ◽  
Lipid Biomarker ◽  
Diversity Assessment

scholarly journals Cultivation and Genomic, Nutritional, and Lipid Biomarker Characterization of Roseiflexus Strains Closely Related to Predominant In Situ Populations Inhabiting Yellowstone Hot Spring Microbial Mats

2010 ◽  
Vol 192 (12) ◽  
pp. 3033-3042 ◽  
Author(s):  
Marcel T. J. van der Meer ◽  
Christian G. Klatt ◽  
Jason Wood ◽  
Donald A. Bryant ◽  
Mary M. Bateson ◽  
...  
Keyword(s):  
National Park ◽  
Microbial Mats ◽  
Hot Spring ◽  
Small Subunit ◽  
Small Subunit Rrna ◽  
Anoxygenic Phototrophs ◽  
Lipid Biomarker ◽  
Genes Encoding

ABSTRACT Roseiflexus sp. strains were cultivated from a microbial mat of an alkaline siliceous hot spring in Yellowstone National Park. These strains are closely related to predominant filamentous anoxygenic phototrophs found in the mat, as judged by the similarity of small-subunit rRNA, lipid distributions, and genomic and metagenomic sequences. Like a Japanese isolate, R. castenholzii, the Yellowstone isolates contain bacteriochlorophyll a, but not bacteriochlorophyll c or chlorosomes, and grow photoheterotrophically or chemoheterotrophically under dark aerobic conditions. The genome of one isolate, Roseiflexus sp. strain RS1, contains genes necessary to support these metabolisms. This genome also contains genes encoding the 3-hydroxypropionate pathway for CO2 fixation and a hydrogenase, which might enable photoautotrophic metabolism, even though neither isolate could be grown photoautotrophically with H2 or H2S as a possible electron donor. The isolates exhibit temperature, pH, and sulfide preferences typical of their habitat. Lipids produced by these isolates matched much better with mat lipids than do lipids produced by R. castenholzii or Chloroflexus isolates.

scholarly journals Lake overturn as a key driver for methane oxidation

2019 ◽  
Author(s):  
M. Zimmermann ◽  
M. J. Mayr ◽  
D. Bouffard ◽  
W. Eugster ◽  
T. Steinsberger ◽  
...  
Keyword(s):  
Methane Oxidation ◽  
Microbial Growth ◽  
Methane Flux ◽  
Strong Wind ◽  
Surface Cooling ◽  
Data Set ◽  
Stratified Lakes ◽  
Methane Oxidizing Bacteria ◽  
Key Driver ◽  
Oxidation Efficiency

AbstractMany seasonally stratified lakes accumulate substantial amounts of the greenhouse gas methane in the anoxic zone. Methane oxidizing bacteria in the water column act as a converter, oxidizing methane into carbon dioxide and biomass before it reaches the atmosphere. Current observations and estimates of this methane oxidation efficiency are diverging, especially for the lake overturn period. Here we combine a model of turbulent mixing, gas exchange and microbial growth with a comprehensive data set for autumn mixing to quantify the relevant physical and microbial processes. We show that the microbial methane converter is effectively transforming the increased methane flux during the overturn period. Only rare events of pronounced surface cooling in combination with persistently strong wind can trigger substantial outgassing. In the context of climate change, these results suggest that changes in the frequency of storms may be even more important for methane emissions from temperate lakes than gradual warming.

scholarly journals Methane distribution and oxidation around the Lena Delta in summer 2013

2017 ◽  
Author(s):  
Ingeborg Bussmann ◽  
Steffen Hackbusch ◽  
Patrick Schaal ◽  
Antje Wichels
Keyword(s):  
Methane Oxidation ◽  
Methane Flux ◽  
Methanotrophic Bacteria ◽  
Riverine Water ◽  
Lena River ◽  
Methane Distribution ◽  
Methane Oxidation Rate ◽  
Mixed Water ◽  
Polar Water ◽  
Lena Delta

Abstract. The Lena River is one of the biggest Russian rivers draining into the Laptev Sea. Due to predicted increasing temperatures, the permafrost areas surrounding the Lena Delta will melt at increasing rates. With this melting, high amounts of methane will reach the waters of the Lena and the adjacent Laptev Sea. Methane oxidation by methanotrophic bacteria is the only biological way to reduce methane concentrations within the system. However, the polar estuary of the Lena River is a challenging environment for bacteria, with strong fluctuations in salinity and temperature. We determined the activity (tracer method) and the abundance (qPCR) of aerobic methanotrophic bacteria. We described the methanotrophic population with MISA; as well as the methane distribution (head space) and other abiotic parameters in the Lena Delta in September 2013. In riverine water (S < 5) we found a median methane concentration of 22 nM, in mixed water (5 < S < 20) the median methane concentration was 19 nM and in polar water (S > 20) a median 28 nM was observed. The Lena River was not the methane source for surface water, and bottom water methane concentrations were mainly influenced by the concentration in surface sediments. However, the methane oxidation rate in riverine and polar water was very similar (0.419 and 0.400 nM/d), but with a higher relative abundance of methanotrophs and a higher estimated diversity with respect to MISA OTUs in the rivine water as compared to polar water. The turnover times of methane ranged from 167 d in mixed water, 91 d in riverine water and only 36 d in polarwater. Also the environmental parameters influencing the methane oxidation rate and the methanotrophic population differed between the water masses. Thus we postulate a riverine methanotrophic population limited by sub-optimal temperatures and substrate concentrations and a polar methanotrophic population being well adapted to the cold and methane poor environment, but limited by the nitrogen content. The diffusive methane flux into the atmosphere ranged from 4–163 µmol m2 d−1 (median 24). For the total methane inventory of the investigated area, the diffusive methane flux was responsible for 8 % loss, compared to only 1 % of the methane consumed by the methanotrophic bacteria within the system.

scholarly journals Interaction between hydrocarbon seepage, chemosynthetic communities and bottom water redox at cold seeps of the Makran accretionary prism: insights from habitat-specific pore water sampling and modeling

2011 ◽  
Vol 8 (5) ◽  
pp. 9763-9811 ◽  
Author(s):  
D. Fischer ◽  
H. Sahling ◽  
K. Nöthen ◽  
G. Bohrmann ◽  
M. Zabel ◽  
...  
Keyword(s):  
Hydrogen Sulfide ◽  
Pore Water ◽  
Bottom Water ◽  
Microbial Mats ◽  
Lower Boundary ◽  
Accretionary Prism ◽  
Anaerobic Oxidation Of Methane ◽  
Cold Seeps ◽  
Remotely Operated Vehicle ◽  
Geochemical Environment

Abstract. The interaction between fluid seepage, bottom water redox, and chemosynthetic communities was studied at cold seeps across one of the world's largest oxygen minimum zones (OMZ) located at the Makran convergent continental margin. Push cores were obtained from seeps within and at the lower boundary of the core-OMZ with a remotely operated vehicle. Extracted pore water was analyzed for sulfide and sulfate contents. Depending on oxygen availability, seeps were either colonized by microbial mats or by mats and macrofauna. The latter, including ampharetid polychaetes and vesicomyid clams, occurred in distinct benthic habitats which were arranged in a concentric fashion around gas orifices. At most sites colonized by microbial mats, hydrogen sulfide was exported into the bottom water. Where macrofauna was widely abundant, hydrogen sulfide was consumed within the sediment. Numerical modeling of pore water profiles was performed in order to assess rates of fluid advection and bioirrigation. While the magnitude of upward fluid flow decreased from 11 cm yr−1 to <1 cm yr−1 and the sulfate/methane transition zone (SMTZ) deepened with increasing distance from the central gas orifice, the fluxes of sulfate into the SMTZ did not significantly differ (6.6–9.3 mol m−2 yr−1). Depth-integrated rates of bioirrigation increased from 162 cm yr−1 in central habitats characterized by microbial mats and sparse macrofauna to 348 cm yr−1 in habitats of large and small vesicomyid clams. These results reveal that chemosynthetic macrofauna inhabiting the outer seep habitats at the lower boundary of the OMZ efficiently bioirrigate and thus transport sulfate into the upper 10 to 15 cm of the sediment. In this way bioirrigation compensates for the lower upward flux of methane in outer habitats and stimulates rates of anaerobic oxidation of methane (AOM) with sulfate high enough to provide sulfide for chemosynthesis. Through bioirrigation macrofauna engineer their geochemical environment and fuel upward sulfide flux via AOM. Due to the introduction of oxygenated bottom water into the sediment via bioirrigation the depth of the sulfide sink gradually deepens towards outer habitats. We therefore suggest that – in addition to the oxygen levels in the water column which determine whether macrofaunal communities can develop or not – it is rather the depth of the SMTZ and thus of sulfide production that determines which chemosynthetic communities are able to exploit the sulfide at depth. Moreover, large vesicomyid clams most efficiently expand the sulfate zone in the sediment and cut off smaller or immobile organisms from the sulfide source.

scholarly journals Interaction between hydrocarbon seepage, chemosynthetic communities, and bottom water redox at cold seeps of the Makran accretionary prism: insights from habitat-specific pore water sampling and modeling

2012 ◽  
Vol 9 (6) ◽  
pp. 2013-2031 ◽  
Author(s):  
D. Fischer ◽  
H. Sahling ◽  
K. Nöthen ◽  
G. Bohrmann ◽  
M. Zabel ◽  
...  
Keyword(s):  
Hydrogen Sulfide ◽  
Pore Water ◽  
Bottom Water ◽  
Microbial Mats ◽  
Accretionary Prism ◽  
Anaerobic Oxidation Of Methane ◽  
Cold Seeps ◽  
Remotely Operated Vehicle ◽  
Geochemical Environment ◽  
The Core

Abstract. The interaction between fluid seepage, bottom water redox, and chemosynthetic communities was studied at cold seeps across one of the world's largest oxygen minimum zones (OMZ) located at the Makran convergent continental margin. Push cores were obtained from seeps within and below the core-OMZ with a remotely operated vehicle. Extracted sediment pore water was analyzed for sulfide and sulfate concentrations. Depending on oxygen availability in the bottom water, seeps were either colonized by microbial mats or by mats and macrofauna. The latter, including ampharetid polychaetes and vesicomyid clams, occurred in distinct benthic habitats, which were arranged in a concentric fashion around gas orifices. At most sites colonized by microbial mats, hydrogen sulfide was exported into the bottom water. Where macrofauna was widely abundant, hydrogen sulfide was retained within the sediment. Numerical modeling of pore water profiles was performed in order to assess rates of fluid advection and bioirrigation. While the magnitude of upward fluid flow decreased from 11 cm yr−1 to <1 cm yr−1 and the sulfate/methane transition (SMT) deepened with increasing distance from the central gas orifice, the fluxes of sulfate into the SMT did not significantly differ (6.6–9.3 mol m−2 yr−1). Depth-integrated rates of bioirrigation increased from 120 cm yr−1 in the central habitat, characterized by microbial mats and sparse macrofauna, to 297 cm yr−1 in the habitat of large and few small vesicomyid clams. These results reveal that chemosynthetic macrofauna inhabiting the outer seep habitats below the core-OMZ efficiently bioirrigate and thus transport sulfate down into the upper 10 to 15 cm of the sediment. In this way the animals deal with the lower upward flux of methane in outer habitats by stimulating rates of anaerobic oxidation of methane (AOM) with sulfate high enough to provide hydrogen sulfide for chemosynthesis. Through bioirrigation, macrofauna engineer their geochemical environment and fuel upward sulfide flux via AOM. Furthermore, due to the introduction of oxygenated bottom water into the sediment via bioirrigation, the depth of the sulfide sink gradually deepens towards outer habitats. We therefore suggest that – in addition to the oxygen levels in the water column, which determine whether macrofaunal communities can develop or not – it is the depth of the SMT and thus of sulfide production that determines which chemosynthetic communities are able to exploit the sulfide at depth. We hypothesize that large vesicomyid clams, by efficiently expanding the sulfate zone down into the sediment, could cut off smaller or less mobile organisms, as e.g. small clams and sulfur bacteria, from the sulfide source.

Sign in / Sign up

Export Citation Format

Share Document