Search Results (8)

Microbial communities of terrestrial mud volcanoes are involved in aerobic and anaerobic methane oxidation, but the biological mechanisms of these processes are still understudied. We have investigated the taxonomic composition, rates of methane oxidation, and metabolic potential of microbial communities in five mud volcanoes of the Taman Peninsula, Russia. Methane oxidation rates measured by the radiotracer technique varied from 2.0 to 460 nmol CH₄ cm⁻³ day⁻¹ in different mud samples. This is the first measurement of high activity of microbial methane oxidation in terrestrial mud volcanos. 16S rRNA gene amplicon sequencing has shown that Bacteria accounted for 65–99% of prokaryotic diversity in all samples. The most abundant phyla were Pseudomonadota, Desulfobacterota, and Halobacterota. A total of 32 prokaryotic genera, which include methanotrophs, sulfur or iron reducers, and facultative anaerobes with broad metabolic capabilities, were detected in relative abundance >5%. The most highly represented genus of aerobic methanotrophs was Methyloprofundus reaching 36%. The most numerous group of anaerobic methanotrophs was ANME-2a-b (Ca. Methanocomedenaceae), identified in 60% of the samples and attaining relative abundance of 54%. The analysis of the metagenome-assembled genomes of a community with high methane oxidation rate indicates the importance of CO₂ fixation, Fe(III) and nitrate reduction, and sulfide oxidation. This study expands current knowledge on the occurrence, distribution, and activity of microorganisms associated with methane cycle in terrestrial mud volcanoes. Full article

A novel aerotolerant anaerobic bacterium (strain M4Ah^T) was isolated from a terrestrial mud volcano (Taman Peninsula, Russia). Cells were small, cell-wall-less, non-motile cocci, 0.32–0.65 μm in diameter. The isolate was a mesophilic, neutrophilic chemoorganoheterotroph, growing on carbohydrates (D-glucose, D-trehalose, D-ribose, D-mannose, D-xylose, D-maltose, D-lactose, D-cellobiose, D-galactose, D-fructose, and D-sucrose), proteinaceous compounds (yeast extract, tryptone), and pyruvate. Strain M4Ah^T tolerated 2% oxygen in the gas phase, was catalase-positive, and showed sustainable growth under microaerobic conditions. The dominant cellular fatty acids of strain M4Ah^T were C_16:0 and C_18:0. The G+C content of the genomic DNA was 32.42%. The closest phylogenetic relative of strain M4Ah^T was Mariniplasma anaerobium from the family Acholeplasmataceae (order Acholeplasmatales, class Mollicutes). Based on the polyphasic characterization of the isolate, strain M4Ah^T is considered to represent a novel species of a new genus, for which the name Peloplasma aerotolerans gen. nov., sp. nov. is proposed. The type strain of Peloplasma aerotolerans is M4Ah^T (=DSM 112561^T = VKM B-3485^T = UQM 41475^T). This is the first representative of the order Acholeplasmatales, isolated from a mud volcano. Full article

The violent eruption of Karabetova Gora mud volcano on 6 May 2000 (Taman Peninsula, 45°12′16″ N; 36°47′05″ E) triggered gas ignition as a giant straight-flow vertical gas flare. The 400 m high, short-lived (~15 min) gas flare left no thermal halo on the ground surface, but the thermal shock caused melting or annealing of mud masses which became dispersed in ≤2 m³ blocks to distances within 30 m around the volcano conduit. The flare reached the maximum temperatures (~1400–1540 °C) at heights from 75 to 250 m, as estimated by a numerical simulation in SigmaFlow. Bulk melting of dehydrated mud masses was mostly limited to <1.5 cm near the surface of the blocks. Porous paralavas at the site consisted of low- and high-silica K-Al glasses (70%–80%) with residual unmolten grains of detrital quartz and fine (<30 µm) new phases: main intermediate members of the magnetite–ulvöspinel solid solutions and plagioclase (An_45-61Ab_37-44Or_2-11 to An_73-90Ab_10-27Or_0.5-1), minor cordierite (X_Fe = 26%–46%), pigeonite (X_Fe = 42%–60%), tridymite, cristobalite, and rare mullite. The metapelitic rocks affected by combustion metamorphism were heterogeneous in terms of phase composition and texture. They failed to attain homogeneity due to the high viscosity of anhydrous silicate melts and brevity of the thermal impact. The revealed features of rocks altered by a giant gas fire may serve as a proxy for phase transformation patterns in highly disequilibrium conditions of a thermal shock, far from the formation conditions of ordinary metamorphic rocks. Full article

Juniperus L. is the second-largest genus of conifers, having the widest distribution of all conifer genera. Its phytogeographic history is, however, obscure due to its very poor fossil record. We described a wood of Juniperus sp. from the lower Maeotian sediments of the Popov Kamen section, Taman Peninsula, South Russia, in order to clarify its taxonomic position shedding light on the phytogeographic history of the genus. This fossil wood was well-preserved by mummification, which allowed for it to be studied by the same methods as used for the anatomical examination of modern woods. The wood from the Popov Kamen section shows the greatest similarity to the extant Mediterranean species J. excelsa, belonging to the section Sabina. This is the first reliable macrofossil evidence of the sect. Sabina from Eurasia convincingly dated to the Miocene. The age of the mummified wood from the Popov Kamen section is consistent with molecular dating of diversification of the lineage comprising juniper species of the sect. Sabina from Europe, Asia and eastern Africa. The wood of Juniperus sp. has not been buried in situ, as it was found in the relatively deep-water marine sediments. The available coeval pollen series and macrofossils of Cupressaceae from the surrounding regions suggest that this wood was likely transferred by sea current from the northwestern side of the Black Sea, which was a part of the Eastern Paratethys. Full article

The introduction of modern methods for the mathematical processing of geological data is one of the promising areas of study and development in the field of geosciences. For example, today mathematical geology makes it possible to reliably identify astronomical cycles by measuring the scalar magnetic parameters of rocks (magnetic susceptibility). The main aim of this study is to develop a mathematical tool for identifying stable oscillation cycles (periods) in the dataset of the magnetic susceptibility of rocks in a geological section. The author’s method (algorithm) is based on the concept of discrete mathematical analysis—an innovative mathematical approach to the analysis of discrete geological and geophysical data. Its reliability is also demonstrated, by comparison with the results obtained by classical methods: Fourier analysis, Lomb periodogram, and REDFIT. The proposed algorithm was applied by the authors to analyze the material of field geological studies of the Zhelezny Rog section (Taman Peninsula). As a result, stable cycles were determined for the Pontian and Lower Maeotian sedimentary strata of the Black Sea Basin (Paratethys). Full article

Terrestrial mud volcanoes (TMVs) are important natural sources of methane emission. The microorganisms inhabiting these environments remain largely unknown. We studied the phylogenetic composition and metabolic potential of the prokaryotic communities of TMVs located in the Taman Peninsula, Russia, using a metagenomic approach. One of the examined sites harbored a unique community with a high abundance of anaerobic methane-oxidizing archaea belonging to ANME-3 group (39% of all 16S rRNA gene reads). The high number of ANME-3 archaea was confirmed by qPCR, while the process of anaerobic methane oxidation was demonstrated by radioisotopic experiments. We recovered metagenome-assembled genomes (MAGs) of archaeal and bacterial community members and analyzed their metabolic capabilities. The ANME-3 MAG contained a complete set of genes for methanogenesis as well as of ribosomal RNA and did not encode proteins involved in dissimilatory nitrate or sulfate reduction. The presence of multiheme c-type cytochromes suggests that ANME-3 can couple methane oxidation with the reduction of metal oxides or with the interspecies electron transfer to a bacterial partner. The bacterial members of the community were mainly represented by autotrophic, nitrate-reducing, sulfur-oxidizing bacteria, as well as by fermentative microorganisms. This study extends the current knowledge of the phylogenetic and metabolic diversity of prokaryotes in TMVs and provides a first insight into the genomic features of ANME-3 archaea. Full article

Mud volcanism is observed in many tectonically active regions worldwide. One of the typical areas of mud volcanic activity is the Taman Peninsula, Russia. In this article, we examine the possibilities of multiscale analysis of remote sensing and morphometric data of different origins, years, scales, and resolutions for studying mud volcanic landscapes. The research is exemplified by the central-northern margin of the Taman Peninsula, where mud volcanism has only been little studied. The data set included one arc-second gridded Advanced Land Observing Satellite World three-dimensional (3D) digital surface model (AW3D30 DSM); a Corona historical declassified satellite photography; high-resolution imagery from an unmanned aerial survey (UAS) conducted with a multi-copter drone DJI Phantom 4 Pro, as well as a series of 1-m gridded morphometric models, including 12 curvatures (minimal, maximal, mean, Gaussian, unsphericity, horizontal, vertical, difference, vertical excess, horizontal excess, accumulation, and ring one) derived from UAS-based images. The data analysis allowed us to clarify the conditions of neotectonic development in the central-northern margin of the Taman Peninsula, as well as to specify manifestations of the mud volcanism in this region. In particular, we were able to detect minor and weakly topographically expressed mud volcanic features (probably, inactive gryphons, and salses), which are hidden by long-term farming practice (e.g., ploughed and covered by soil). Full article

The coastal peloidis a peculiar and poorly-studied geological substance. Peloids occurin the Bugaz, Kiziltash, and Vityazevolimans and the Chemburka Lake on the southern coast of the Taman Peninsula. The studied peloids are dark-colored mud enriched in hydrogen sulfide and methane and constitute the uppermost 10–20 cm of bottom sediments. Being geologically unique, the coastal peloids of the Taman Peninsula can be recognized as ageoheritage site. Their uniqueness is linked to sediment type, biogeochemical processes, economic value, and depositional environment. The most typical peloids are found in the BugazLiman and the Chemburka Lake, proposed as geosites. The recognized coastal geoheritage site can be used for the purposes of science, education, and tourism, and its utility seems to be especially high because of its close location to the big resort area of Anapa. It appears to be important to balance management of this geoheritagesite with peloid extraction for balneological purposes. The studied coastal muds should be involved into the regional planning programs aimed at sustainable development (international experience and, particularly, some examples from the British coasts should be taken into consideration). Particularly, it is necessary to put peloid use into the context of regional planning and sustainable natural resource management. Full article