scholarly journals Sulfur and Methane-Oxidizing Microbial Community in a Terrestrial Mud Volcano Revealed by Metagenomics

2020 ◽  
Vol 8 (9) ◽  
pp. 1333
Author(s):  
Andrey V. Mardanov ◽  
Vitaly V. Kadnikov ◽  
Alexey V. Beletsky ◽  
Nikolai V. Ravin

Mud volcanoes are prominent geological structures where fluids and gases from the deep subsurface are discharged along a fracture network in tectonically active regions. Microbial communities responsible for sulfur and methane cycling and organic transformation in terrestrial mud volcanoes remain poorly characterized. Using a metagenomics approach, we analyzed the microbial community of bubbling fluids retrieved from an active mud volcano in eastern Crimea. The microbial community was dominated by chemolithoautotrophic Campylobacterota and Gammaproteobacteria, which are capable of sulfur oxidation coupled to aerobic and anaerobic respiration. Methane oxidation could be enabled by aerobic Methylococcales bacteria and anaerobic methanotrophic archaea (ANME), while methanogens were nearly absent. The ANME community was dominated by a novel species of Ca. Methanoperedenaceae that lacked nitrate reductase and probably couple methane oxidation to the reduction of metal oxides. Analysis of two Ca. Bathyarchaeota genomes revealed the lack of mcr genes and predicted that they could grow on fatty acids, sugars, and proteinaceous substrates performing fermentation. Thermophilic sulfate reducers indigenous to the deep subsurface, Thermodesulfovibrionales (Nitrospirae) and Ca. Desulforudis (Firmicutes), were found in minor amounts. Overall, the results obtained suggest that reduced compounds delivered from the deep subsurface support the development of autotrophic microorganisms using various electron acceptors for respiration.

Author(s):  
C. Jatu

Mud volcanoes in Grobogan are referred as the Grobogan Mud Volcanoes Complex in Central Java where there is evidence of oil seepages. This comprehensive research is to determine the characteristics and hydrocarbon potential of the mud volcanoes in the Central Java region as a new opportunity for hydrocarbon exploration. The Grobogan Mud Volcano Complex consists of eight mud volcanoes that have its characteristics based on the study used the geological surface data and seismic literature as supporting data on eight mud volcanoes. The determination of geological surface characteristics is based on geomorphological analysis, laboratory analysis such as petrography, natural gas geochemistry, water analysis, mud geochemical analysis and biostratigraphy. Surface data and subsurface data are correlated, interpreted, and validated to make mud volcano system model. The purpose of making the mud volcanoes system model is to identify the hydrocarbon potential in Grobogan. This research proved that each of the Grobogan Mud Volcanoes has different morphological forms. Grobogan Mud Volcanoes materials are including muds, rock fragments, gas, and water content with different elemental values. Based on this research result, there are four mud volcano systems models in Central Java, they are Bledug Kuwu, Maesan, Cungkrik, and Crewek type. The source of the mud is from Ngimbang and Tawun Formation (Middle Eocene to Early Miocene) from biostratigraphy data and it been correlated with seismic data. Grobogan Mud Volcanoes have potential hydrocarbons with type III kerogen of organic matter (gas) and immature to early mature level based on TOC vs HI cross plot. The main product are thermogenic gas and some oil in relatively small quantities. Water analysis shows that it has mature sodium chloride water. This analysis also shows the location was formed within formations that are deposited in a marine environment with high salinity. Research of mud volcanos is rarely done in general. However, this comprehensive research shows the mud volcano has promising hydrocarbon potential and is a new perspective on hydrocarbon exploration.


2020 ◽  
Vol 8 (3) ◽  
pp. 386 ◽  
Author(s):  
Maxim Muravyov ◽  
Anna Panyushkina

A two-step process, which involved ferric leaching with biologically generated solution and subsequent biooxidation with the microbial community, has been previously proposed for the processing of low-grade zinc sulfide concentrates. In this study, we carried out the process of complete biological oxidation of the product of ferric leaching of the zinc concentrate, which contained 9% of sphalerite, 5% of chalcopyrite, and 29.7% of elemental sulfur. After 21 days of biooxidation at 40 °C, sphalerite and chalcopyrite oxidation reached 99 and 69%, respectively, while the level of elemental sulfur oxidation was 97%. The biooxidation residue could be considered a waste product that is inert under aerobic conditions. The results of this study showed that zinc sulfide concentrate processing using a two-step treatment is efficient and promising. The microbial community, which developed during biooxidation, was dominated by Acidithiobacillus caldus, Leptospirillum ferriphilum, Ferroplasma acidiphilum, Sulfobacillus thermotolerans, S. thermosulfidooxidans, and Cuniculiplasma sp. At the same time, F. acidiphilum and A. caldus played crucial roles in the oxidation of sulfide minerals and elemental sulfur, respectively. The addition of L. ferriphilum to A. caldus during biooxidation of the ferric leach product proved to inhibit elemental sulfur oxidation.


The Holocene ◽  
2019 ◽  
Vol 29 (6) ◽  
pp. 975-991 ◽  
Author(s):  
Lisa Borgatti ◽  
Bosi Giovanna ◽  
Bracci Antonio Edoardo ◽  
Cremonini Stefano ◽  
Falsone Gloria ◽  
...  

Among natural hazards, mud volcanoes can damage property and infrastructures and affect hillslope evolution at different spatial and temporal scales. The results of 10-year-long multidisciplinary investigations performed on a Roman-age archaeological site, La Rovina di Montegibbio, are presented, showing a peculiar example of mutual interplay between human settlement and geological forcing in the mud-volcanic environment. The site (350 m a.s.l.) lies at the termination of the upper Secchia River catchment, near the town of Sassuolo (Modena Province). Here, a 4-km-long mud volcano belt borders the Apennines chain front, comprising one of the most prominent mud volcanoes of Italy ( Salsa di Montegibbio), and the still-active chain hinge tectonics gives origin to gas and oil seeps. Based on geological, geoarchaeological, palaeobotanical, geochemical, geophysical records and analytical data, we unravel the onset, the evolution and the abandonment of the settlement in relation to the existence of a previously unknown mud volcano, belonging to the larger Montegibbio mud volcano system. The damages affecting the Roman-age buildings record the ground deformations in the context of mud volcano tectonics. In particular, the pattern of faults set buried under the archaeological site is shown and compared with that of the main mud volcano conduit. At least two Roman-age eruptive episodes have been recorded, whose ejected muds are geochemically characterized. The first recorded eruption must be regarded as the reason for the initial location and function of the sacred ancient settlement. The final site abandonment was because of subsequent severe ground deformations affecting the hillslope as a consequence of mud volcano activity.


2020 ◽  
Vol 5 (1) ◽  
pp. 64-77
Author(s):  
L. I. Ryabushko ◽  
A. V. Bondarenko

Mud volcanoes are one of unique natural phenomena widely spread around the world. They can be found in Crimea, including the Bulganak sopochnoe field – the largest cluster of active mud volcanoes on the peninsula (45°25′29.04″N, 36°27′51.64″E). Study of mud volcano microalgae in Crimea, as well as in other regions of Russia, has not been conducted so far. Therefore, scientific interest is caused by need and urgency of the study of these volcanoes. First data on microalgae species composition of active mud volcanoes are presented in this article. Samples collected by O. Yu. Eremin (03.08.2012 and 13.04.2013) in the upper 2–3-cm layer of suspension and in surface water were investigated. The ranges of salinity and water temperature were 27–32 g per L and +28…+31 °C, respectively. Microalgae species composition was determined in water preparations using Axioskop 40 (Carl Zeiss) light microscope at magnification of 10×40 with software AxioVision Rel. 4.6. Totally 16 taxa were found: Cyanobacteria (1), Dinophyta (2), Bacillariophyta (6), and Euglenophyta (7). Of these, cyanobacteria Chamaecalyx swirenkoi (Schirshov) Komárek et Anagnostidis, 1986 was found by us in the mud volcano in August 2012. Pennate species of diatoms were also identified – single living (of genera Cylindrotheca (Ehrenberg) Reimann & J. C. Lewin, Lyrella Karajeva, and Nitzschia Hassall) and colonial species (of genera Berkeleya Greville and Pseudo-nitzschia H. Peragallo). The brackish-water, benthic, boreal-tropical species Nitzschia thermaloides Hustedt was recorded for the algal flora of Crimea, the Black Sea, and the Sea of Azov for the first time. Euglenophytes were also found in the samples – 5 species of the genus Trachelomonas Ehrenberg and 2 species of the genus Strombomonas Deflandre. Of all the species found in the mud volcano ecotope, 7 species are common for the Black Sea, and 9 species, including 3 euglenophytes, are common for the Sea of Azov. It is shown that by characteristics of halobility, species found in the mud volcano belong to freshwater complex (53 %), with a significant share of marine (27 %) and brackish-water (20 %) species. Of the phytogeographic flora elements, boreal species make up 33 %, boreal-tropical – 47 %, and cosmopolites – 20 %. Three species of potentially toxic algae are recorded: diatom Pseudo-nitzschia prolongatoides (Hasle) Hasle, 1993, as well as dinophytes Prorocentrum lima (Ehrenberg) Dodge, 1975 and Alexandrium tamiyavanichii Balech, 1994. The last species is marine, boreal-tropical, and new to the algology of Crimea, the Black Sea, and the Sea of Azov. In the article, own and literary data on morphology, ecology, and phytogeography of species, as well as on their general distribution in different waterbodies of the world, are also presented. Some microalgae species are indicators of saprobity; they are able to participate in purification of water from organic substances. Photos of mud volcanoes and micrographs of some species are presented.


2020 ◽  
Author(s):  
Yuri Fialko

Abstract Strength of the upper brittle part of the Earth's lithosphere controls deformation styles in tectonically active regions, surface topography, seismicity, and the occurrence of plate tectonics, yet it remains one of the least constrained and most debated quantities in geophysics. Seismic data (in particular, earthquake focal mechanisms) have been used to infer orientation of the principal stress axes. Here I show that the focal mechanism data can be combined with information from precise earthquake locations to place robust constraints not only on the orientation, but also on the magnitude of absolute stress at depth. The proposed method uses machine learning to identify quasi-linear clusters of seismicity associated with active faults. A distribution of the relative attitudes of conjugate faults carries information about the amplitude and spatial heterogeneity of the deviatoric stress and frictional strength in the seismogenic zone. The observed diversity of dihedral angles between conjugate faults in the Ridgecrest (California, USA) area that hosted a recent sequence of strong earthquakes suggests the effective coefficient of friction of 0.4-0.6, and depth-averaged shear stresses on the order of 25-40 MPa, intermediate between predictions of the "strong" and "weak" fault theories.


2019 ◽  
Author(s):  
Tuna Eken

Abstract. Proper estimate of moment magnitude that is a physical measure of the energy released at earthquake source is essential for better seismic hazard assessments in tectonically active regions. Here a coda wave modeling approach that enables the source displacement spectrum modeling of examined event was used to estimate moment magnitude of central Anatolia earthquakes. To achieve this aim, three component waveforms of local earthquakes with magnitudes 2.0 ≤ ML ≤ 5.2 recorded at 72 seismic stations which have been operated between 2013 and 2015 within the framework of the CD-CAT passive seismic experiment. An inversion on the coda wave traces of each selected single event in our database was performed in five different frequency bands between 0.75 and 12 Hz. Our resultant moment magnitudes (MW-coda) exhibit a good agreement with routinely reported local magnitude (ML) estimates for study area. Finally, we present an empirical relation between MW-coda and ML for central Anatolian earthquakes.


2020 ◽  
Vol 185 ◽  
pp. 103083 ◽  
Author(s):  
S.A. Binnie ◽  
K.R. Reicherter ◽  
P. Victor ◽  
G. González ◽  
A. Binnie ◽  
...  

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