Input from the Deep: Hot Vents and Cold Seeps

Herzig, Peter; Hannington, Mark D.

doi:10.1007/3-540-32144-6_13

Cited by 18 publications

(14 citation statements)

References 115 publications

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“…In our experiments, fractal growth can occur over a wide range of conditions, at pH values between 9.5 and 11.3 and [Ba] between 1.25 and 40 mmol/L (see Figure ), while the curvilinear growth of helicoidal biomorphs is restricted between pH 10.1 and 11.3, and [Ba] between 10 and 40 mmol/L. These barium concentrations are much higher than that of modern seawater ([Ba] = 0.15 μmol/kg, Herzig & Hannington, ), and modern hydrothermal fluids ([Ba] = 1.3–54 μmol/kg, (Charlou et al., ; Ludwig, Kelley, Butterfield, Nelson, & Früh‐Green, ; Von Damm, ). However, in Archean hydrothermal fluids that leached predominantly ultramafic crust, the barium concentration may have been higher.…”

Section: Discussionmentioning

confidence: 53%

A morphogram for silica‐witherite biomorphs and its application to microfossil identification in the early earth rock record

et al. 2018

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Archean hydrothermal environments formed a likely site for the origin and early evolution of life. These are also the settings, however, were complex abiologic structures can form. Low‐temperature serpentinization of ultramafic crust can generate alkaline, silica‐saturated fluids in which carbonate–silica crystalline aggregates with life‐like morphologies can self‐assemble. These “biomorphs” could have adsorbed hydrocarbons from Fischer–Tropsch type synthesis processes, leading to metamorphosed structures that resemble carbonaceous microfossils. Although this abiogenic process has been extensively cited in the literature and has generated important controversy, so far only one specific biomorph type with a filamentous shape has been discussed for the interpretation of Archean microfossils. It is therefore critical to precisely determine the full distribution in morphology and size of these biomorphs, and to study the range of plausible geochemical conditions under which these microstructures can form. Here, a set of witherite‐silica biomorph synthesis experiments in silica‐saturated solutions is presented, for a range of pH values (from 9 to 11.5) and barium ion concentrations (from 0.6 to 40 mmol/L BaCl2). Under these varying conditions, a wide range of life‐like structures is found, from fractal dendrites to complex shapes with continuous curvature. The size, spatial concentration, and morphology of the biomorphs are strongly controlled by environmental parameters, among which pH is the most important. This potentially limits the diversity of environments in which the growth of biomorphs could have occurred on Early Earth. Given the variety of the observed biomorph morphologies, our results show that the morphology of an individual microstructure is a poor criterion for biogenicity. However, biomorphs may be distinguished from actual populations of cellular microfossils by their wide, unimodal size distribution. Biomorphs grown by diffusion in silica gel can be differentiated by their continuous gradient in size, spatial density, and morphology along the direction of diffusion.

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Section: Discussionmentioning

confidence: 53%

A morphogram for silica‐witherite biomorphs and its application to microfossil identification in the early earth rock record

et al. 2018

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“…Subsamples of the chimney structure were obtained from vertical and horizontal sections distinguished on the basis of morphological features. In the case of hydrothermal vents with slowly flowing effluent, it has often been observed that the top part of the chimney is covered with weakly packed materials, consisting of chalcopyrite, pyrrhotite, and anhydrite on solid sulfide materials (21,22,33). The chimney investigated in the present study was obtained from a black smoker with vigorously flowing effluent, and no such soft head-structure was observed.…”

Section: Resultsmentioning

confidence: 74%

“…At the shallow marine hydrothermal vent site, temperature and pH ranging from approximately 70°C at pH 5 to 20°C at pH 7 were formed over a distance of several meters (47). The potential impact of the environment on a microbial community might be much more intense in deep-sea hydrothermal systems, since gradients are expected to exist in the range of approximately 300°C at pH 3 to 4°C at pH 6 to 7 in the case of a black smoker investigated (16,17) and from 350 to 400°C to 4°C in the case of the typical midocean-ridge systems (21). In the range of such extraordinary thermal gradients of the deep-sea vents, the archaeal components may play a much more important role in the formation and activity of a microbial community than in the shallow vents.…”

Section: Discussionmentioning

confidence: 99%

Distribution of Archaea in a Black Smoker Chimney Structure

Takai¹,

Komatsu²,

Inagaki³

et al. 2001

Appl Environ Microbiol

260

279

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Archaeal community structures in microhabitats in a deep-sea hydrothermal vent chimney structure were evaluated through the combined use of culture-independent molecular analyses and enrichment culture methods. A black smoker chimney was obtained from the PACMANUS site in the Manus Basin near Papua New Guinea, and subsamples were obtained from vertical and horizontal sections. The elemental composition of the chimney was analyzed in different subsamples by scanning electron microscopy and energy-dispersive X-ray spectroscopy, indicating that zinc and sulfur were major components while an increased amount of elemental oxygen in exterior materials represented the presence of oxidized materials on the outer surface of the chimney. Terminal restriction fragment length polymorphism analysis revealed that a shift in archaeal ribotype structure occurred in the chimney structure. Through sequencing of ribosomal DNA (rDNA) clones from archaeal rDNA clone libraries, it was demonstrated that the archaeal communities in the chimney structure consisted for the most part of hyperthermophilic members and extreme halophiles and that the distribution of such extremophiles in different microhabitats of the chimney varied. The results of the culture-dependent analysis supported in part the view that changes in archaeal community structures in these microhabitats are associated with the geochemical and physical dynamics in the black smoker chimney.Since the discovery of deep-sea hydrothermal vents in 1979 (12, 15), various microorganisms have been isolated from global deep-sea hydrothermal vent environments (26,27,29). Hyperthermophiles and thermophiles, including members of both the bacterial and archaeal domains, are the most frequently isolated microorganisms, and their physiological properties likely reflect the extraordinary environmental settings of the deep-sea hydrothermal vents (9,10,18,23,28,42,43,53,56,60). In addition, recent culture-independent molecular approaches have revealed the presence of as-yet-uncultivated thermophiles showing substantial phylogenetic diversity in the deep-sea hydrothermal vent environments (27,38,39,44,51). Relatively little is known about the ecological significance and geomicrobiological function of the extremophilic microbial communities found, as the occurrence, abundance, and distribution of the microbial communities associated with the formation of diverse geochemical and physical gradients remain to be elucidated.A deep-sea hydrothermal vent chimney, formed by chemical interaction between cold seawater and hot vent water, is a distinctive structure in the deep-sea hydrothermal fields and is largely composed of sulfide materials. In the chimney structures and the underlying sulfide mounds, steep environmental gradients of temperature, pH, oxidation-redox potential, and various chemicals can be formed by equilibration between the vent water and the seawater, and these provide diverse micro-

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“…As is well known, because of the narrow margin of stability of clathrates regarding pressure and temperature, sequestration should be made for depth values of around 1-3 km, making the process considerably more expensive. Another problem associated with this method is that the natural destabilization of clathrates in continental slopes (cold seeps) is a geologically frequent phenomenon (Herzig and Hannington, 1999); this is one of the natural factors that apparently contributes significantly to the greenhouse effect, so this method does not guarantee long-term sequestration.…”

Section: Introductionmentioning

confidence: 99%

Geochemical potentiality of glauconitic shelf sediments for sequestering atmospheric CO2 of anthropogenic origin

Fernández-Bastero

Garcı́a²,

Santos

et al. 2005

Cienc. Mar.

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ResumenEn este estudio se analizó experimentalmente la velocidad de disolución de la glauconita en función del pH. Los resultados se utilizaron para modelar la evolución geoquímica de sedimentos marinos glauconíticos de la plataforma continental, ante una inyección de CO 2 , y estimar las posibilidades y limitaciones para su fijación en forma de minerales a través de reacciones de carbonatación. Los resultados experimentales muestraron como, en condiciones ácidas, la glauconita es ligeramente más soluble que otros silicatos, dando lugar a productos carbonatados más insolubles. El mecanismo de disolución es incongruente a valores de pH muy ácidos y tiende a ser congruente para valores intermedios y neutros. La superficie reactiva disminuye en el curso del proceso como resultado de la formación de un residuo amorfo. Los datos cinéticos se han empleado para modelar las reacciones de carbonatación en sedimentos marinos mediante cálculos especiación-reacción. En el estudio se evidencia que, para el caso de la glauconita, la eficacia en la fijación de CO 2 depende principalmente de dos factores: la propia cinética de disoluciónespeciación del CO 2 en los sedimentos y la cinética de liberación del Fe 2+ . La mayor limitación del proceso de cara a su implementación, es la evolución del pH hacia valores ácidos. Los resultados sugieren que, a mediano plazo, este proceso podría ser optimizado de forma técnica modificando la respuesta de neutralización de los sedimentos mediante la inyección de agentes alcalinizantes y con una selección adecuada, tanto del modo de inyección como de la composición de los sedimentos y de las zonas diagenéticas más favorables.Palabras clave: disolución de glauconita, baño de flujo continuo, fijación de CO 2 , reacciones de carbonatación, modelos especiación-reacción. AbstractAn experimental analysis was made of the glauconite dissolution rate as a function of pH. The results were used to model the geochemical evolution of glauconitic shelf sediments injected with CO 2 and estimate the possibilities and limitations for sequestering CO 2 in the form of minerals through carbonation reactions. The experimental results show how, under acidic conditions, glauconite is slightly more soluble than other silicates, producing more insoluble carbonated products. The dissolution mechanism is incongruent at very acidic pH values and tends to be congruent at intermediate and neutral values. The reactive surface decreases during the process as a result of the formation of an amorphous residue. Kinetic data were used to model the reactions of carbonation in marine sediments using reaction/speciation calculations. This study shows that, in the case of glauconite, the efficiency of CO 2 sequestration depends primarily on two factors: the dissolution/speciation kinetics of CO 2 in sediments and the kinetics of Fe 2+ release. The greatest limitation for the implementation of this process is that pH evolves to more acidic values. The results suggest that, in the medium term, this process could be technically optimiz...

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Input from the Deep: Hot Vents and Cold Seeps

Cited by 18 publications

References 115 publications

A morphogram for silica‐witherite biomorphs and its application to microfossil identification in the early earth rock record

A morphogram for silica‐witherite biomorphs and its application to microfossil identification in the early earth rock record

Distribution of Archaea in a Black Smoker Chimney Structure

Geochemical potentiality of glauconitic shelf sediments for sequestering atmospheric CO2 of anthropogenic origin

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