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  • 1
    Electronic Resource
    Electronic Resource
    Novel microbial communities of the Haakon Mosby mud volcano and their role as a methane sink (2006)
    [s.l.] : Nature Publishing Group
    Nature 443 (2006), S. 854-858 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Mud volcanism is an important natural source of the greenhouse gas methane to the hydrosphere and atmosphere. Recent investigations show that the number of active submarine mud volcanoes might be much higher than anticipated (for example, see refs 3–5), and that gas emitted ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/nature05227
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    Paper (German National Licenses)
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  • 2
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    Microbial effects on biofilm calcification, ambient water chemistry and stable isotope records in a highly supersaturated setting (Westerhöfer Bach, Germany) (2008)
    Elsevier
    In:  Palaeogeography, Palaeoclimatology, Palaeoecology, 262 (1-2). pp. 91-106.
    Details
    Publication Date: 2018-11-07
    Description: Cyanobacteria-dominated biofilms in a CO2-degassing karst-water creek (Westerhöfer Bach, Germany) were investigated with regard to the effects of microbial activity on CaCO3 precipitation, water chemistry of micro- and macroenvironments, stable isotopic records, and tufa fabric formation. Ex situ microelectrode measurements of pH, O2, Ca2+ and CO32− revealed that annually laminated calcified biofilms composed mainly of filamentous cyanobacteria (tufa stromatolites) strongly induced CaCO3 precipitation by photosynthesis under illumination, but inhibited precipitation by respiration in the dark. In contrast, endolithic cyanobacterial biofilms and mosses did not cause photosynthesis-induced precipitation under experimental conditions. No spontaneous precipitation occurred on bare limestone substrates, despite high calcite supersaturation of the ambient water. Mass balance calculations suggest that biofilm photosynthesis was responsible for 10–20% of Ca2+ loss in the creek, while the remaining Ca2+ loss derived from physicochemical precipitation on branches, leaves and as fine-grained calcite particles. Neither analysis of bulk water chemistry nor oxygen nor carbon stable isotopic records of the tufa stromatolites confirmed photosynthetic effects, despite the evident photosynthesis-induced calcite precipitation. Oxygen stable isotopic values reflected seasonal changes in water temperature, and carbon stable isotope values probably recorded carbon isotopic composition of dissolved inorganic carbon in the creek water. Annual lamination and fabric formation of the tufa stromatolites is suggested to vary with photosynthesis-induced calcite precipitation rates that are affected by temperature dependency of diffusion coefficients. Photosynthesis-induced precipitation resulted in encrusted cyanobacterial sheaths, reflecting syntaxial overgrowth of microcrystalline cyanobacterial tubes by microspar, instead of microcrystalline sheath impregnation, which was previously suggested as an indicator of photosynthesis-induced precipitation. Therefore, sheath impregnation or encrustation by CaCO3 cannot be used to distinguish photosynthesis-induced from physicochemically-induced CaCO3 precipitation.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1016/j.palaeo.2008.02.011
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 3
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    Eruption of a deep-sea mud volcano triggers rapid sediment movement (2014)
    Nature Publishing Group
    In:  Nature Communications, 5 (5385).
    Details
    Publication Date: 2019-07-10
    Description: Submarine mud volcanoes are important sources of methane to the water column. However, the temporal variability of their mud and methane emissions is unknown. Methane emissions were previously proposed to result from a dynamic equilibrium between upward migration and consumption at the seabed by methane-consuming microbes. Here we show non-steady-state situations of vigorous mud movement that are revealed through variations in fluid flow, seabed temperature and seafloor bathymetry. Time series data for pressure, temperature, pH and seafloor photography were collected over 431 days using a benthic observatory at the active Hakon Mosby Mud Volcano. We documented 25 pulses of hot subsurface fluids, accompanied by eruptions that changed the landscape of the mud volcano. Four major events triggered rapid sediment uplift of more than a metre in height, substantial lateral flow of muds at average velocities of 0.4m per day, and significant emissions of methane and CO2 from the seafloor.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
    Format: text
    Format: text
    DOI: 10.1038/ncomms6385
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 4
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    Metabolically active microbial communities in marine sediment under high-CO2 and low-pH extremes (2013)
    Nature Publishing Group
    In:  The ISME Journal, 7 . pp. 555-567.
    Details
    Publication Date: 2019-09-23
    Description: Sediment-hosting hydrothermal systems in the Okinawa Trough maintain a large amount of liquid, supercritical and hydrate phases of CO2 in the seabed. The emission of CO2 may critically impact the geochemical, geophysical and ecological characteristics of the deep-sea sedimentary environment. So far it remains unclear whether microbial communities that have been detected in such high-CO2 and low-pH habitats are metabolically active, and if so, what the biogeochemical and ecological consequences for the environment are. In this study, RNA-based molecular approaches and radioactive tracer-based respiration rate assays were combined to study the density, diversity and metabolic activity of microbial communities in CO2-seep sediment at the Yonaguni Knoll IV hydrothermal field of the southern Okinawa Trough. In general, the number of microbes decreased sharply with increasing sediment depth and CO2 concentration. Phylogenetic analyses of community structure using reverse-transcribed 16S ribosomal RNA showed that the active microbial community became less diverse with increasing sediment depth and CO2 concentration, indicating that microbial activity and community structure are sensitive to CO2 venting. Analyses of RNA-based pyrosequences and catalyzed reporter deposition-fluorescence in situ hybridization data revealed that members of the SEEP-SRB2 group within the Deltaproteobacteria and anaerobic methanotrophic archaea (ANME-2a and -2c) were confined to the top seafloor, and active archaea were not detected in deeper sediments (13–30 cm in depth) characterized by high CO2. Measurement of the potential sulfate reduction rate at pH conditions of 3–9 with and without methane in the headspace indicated that acidophilic sulfate reduction possibly occurs in the presence of methane, even at very low pH of 3. These results suggest that some members of the anaerobic methanotrophs and sulfate reducers can adapt to the CO2-seep sedimentary environment; however, CO2 and pH in the deep-sea sediment were found to severely impact the activity and structure of the microbial community.
    Type: Article , PeerReviewed
    Format: text
    Format: other
    Format: text
    Format: text
    Format: text
    Format: text
    DOI: 10.1038/ismej.2012.124
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 5
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    Biological and chemical sulfide oxidation in a Beggiatoa inhabited marine sediment (2007)
    Nature Publishing Group
    In:  The ISME Journal, 1 (4). pp. 341-353.
    Details
    Publication Date: 2016-05-25
    Description: The ecological niche of nitrate-storing Beggiatoa, and their contribution to the removal of sulfide were investigated in coastal sediment. With microsensors a clear suboxic zone of 2-10cm thick was identified, where neither oxygen nor free sulfide was detectable. In this zone most of the Beggiatoa were found, where they oxidize sulfide with internally stored nitrate. The sulfide input into the suboxic zone was dominated by an upward sulfide flux from deeper sediment, whereas the local production in the suboxic zone was much smaller. Despite their abundance, the calculated sulfide-oxidizing capacity of the Beggiatoa could account for only a small fraction of the total sulfide removal in the sediment. Consequently, most of the sulfide flux into the suboxic layer must have been removed by chemical processes, mainly by precipitation with Fe2+ and oxidation by Fe(III), which was coupled with a pH increase. The free Fe2+ diffusing upwards was oxidized by Mn(IV), resulting in a strong pH decrease. The nitrate storage capacity allows Beggiatoa to migrate randomly up and down in anoxic sediments with an accumulated gliding distance of 4m before running out of nitrate. We propose that the steep sulfide gradient and corresponding high sulfide flux, a typical characteristic of Beggiatoa habitats, is not needed for their metabolic performance, but rather used as a chemotactic cue by the highly motile filaments to avoid getting lost at depth in the sediment. Indeed sulfide is a repellant for Beggiatoa.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1038/ismej.2007.50
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 6
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    Suitability analysis and revised strategies for marine environmental carbon capture and storage (CCS) monitoring (2021)
    Elsevier
    Details
    Publication Date: 2024-02-07
    Description: Highlights • Approaches for CO2 leakage detection, attribution and quantification monitoring exist. • Many approaches cover multiple monitoring tasks simultaneously. • Sonars and chemical sensors on ships or AUVs can cover large areas. • Newer, more specific technologies can detect, verify and quantify smaller, localised leaks. Environmental monitoring of offshore Carbon Capture and Storage (CCS) complexes requires robust methodologies and cost-effective tools to detect, attribute and quantify CO2 leakage in the unlikely event it occurs from a sub-seafloor reservoir. Various approaches can be utilised for environmental CCS monitoring, but their capabilities are often undemonstrated and more detailed monitoring strategies need to be developed. We tested and compared different approaches in an offshore setting using a CO2 release experiment conducted at 120 m water depth in the Central North Sea. Tests were carried out over a range of CO2 injection rates (6 - 143 kg d−1) comparable to emission rates observed from abandoned wells. Here, we discuss the benefits and challenges of the tested approaches and compare their relative cost, temporal and spatial resolution, technology readiness level and sensitivity to leakage. The individual approaches demonstrate a high level of sensitivity and certainty and cover a wide range of operational requirements. Additionally, we refer to a set of generic requirements for site-specific baseline surveys that will aid in the interpretation of the results. Critically, we show that the capability of most techniques to detect and quantify leakage exceeds the currently existing legal requirements.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
    Format: text
    Format: text
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 7
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    Evidence for fungal and chemodenitrification based N2O flux from nitrogen impacted coastal sediments (2017)
    Nature Publishing Group
    Details
    Publication Date: 2022-05-25
    Description: © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 8 (2017): 15595, doi:10.1038/ncomms15595.
    Description: Although increasing atmospheric nitrous oxide (N2O) has been linked to nitrogen loading, predicting emissions remains difficult, in part due to challenges in disentangling diverse N2O production pathways. As coastal ecosystems are especially impacted by elevated nitrogen, we investigated controls on N2O production mechanisms in intertidal sediments using novel isotopic approaches and microsensors in flow-through incubations. Here we show that during incubations with elevated nitrate, increased N2O fluxes are not mediated by direct bacterial activity, but instead are largely catalysed by fungal denitrification and/or abiotic reactions (e.g., chemodenitrification). Results of these incubations shed new light on nitrogen cycling complexity and possible factors underlying variability of N2O fluxes, driven in part by fungal respiration and/or iron redox cycling. As both processes exhibit N2O yields typically far greater than direct bacterial production, these results emphasize their possibly substantial, yet widely overlooked, role in N2O fluxes, especially in redox-dynamic sediments of coastal ecosystems.
    Description: D.D.B. acknowledges support from the Max Planck Institute for Marine Microbiology. This work was supported by the National Science Foundation grants to W.Z. and S.D.W. (OCE-1260373) and to S.D.W. (EAR-1252161).
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 8
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    Eruption of a deep-sea mud volcano triggers rapid sediment movement (2014)
    Nature Publishing Group
    Details
    Publication Date: 2022-05-26
    Description: © The Author(s), 2014. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 5 (2014): 5385, doi:10.1038/ncomms6385.
    Description: Submarine mud volcanoes are important sources of methane to the water column. However, the temporal variability of their mud and methane emissions is unknown. Methane emissions were previously proposed to result from a dynamic equilibrium between upward migration and consumption at the seabed by methane-consuming microbes. Here we show non-steady-state situations of vigorous mud movement that are revealed through variations in fluid flow, seabed temperature and seafloor bathymetry. Time series data for pressure, temperature, pH and seafloor photography were collected over 431 days using a benthic observatory at the active Håkon Mosby Mud Volcano. We documented 25 pulses of hot subsurface fluids, accompanied by eruptions that changed the landscape of the mud volcano. Four major events triggered rapid sediment uplift of more than a metre in height, substantial lateral flow of muds at average velocities of 0.4 m per day, and significant emissions of methane and CO2 from the seafloor.
    Description: Participation of the Sentry AUV and TETHYS team from WHOI was funded by the Arctic Research Initiative of WHOI’s Ocean and Climate Change Institute and the NASA ASTEP grant NNX09AB76G. Additional funds were made available by the AWI, the Max Planck Society and the DFG METEOR/MERIAN programme, as well as the Leibniz programme to A.B.
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
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