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31.
Background, aim, and scope Exploited gas fields and underground gasholders are specific sources of increasing methane concentration. Methane migrates
into the soils by diffusion and convection through natural and technogenic cracks in geological structures and influences
the function of the soils. Soil cover of gas-bearing area functions as a specific, bilateral, periodically penetrating, geomembrane.
Soils shield, transform, and differentiate migrating fluxes of technogenic-allochthonous methane, preventing its emission
to the atmosphere. Problems of methane’s emission are rather current at the present, as methane is the second in importance
after CO2 greenhouse gas, since its concentration in the atmosphere annually grows by approximately 1%. By global estimations, methane
emissions in the gas industry make about 8% of annual receipt to the atmosphere, equal on the average to 500 Тg per a year
(Cicerone and Oremland, Global Biogeochem Cy 2:299–327, 1988). But these calculations are based on the account of the technological losses making 3–12% from the mining of natural gas.
The contribution of migratory methane fluxes to the atmosphere, as a rule, is not considered. The need for research of soil
cover functioning on gas-bearing areas is explained by the fact that processes of methane oxidation, its transformation in
soils, and emission to the atmosphere at these objects are now practically not being studied. The aim of our study was to
reveal specific processes of soil function and formation on gas-bearing areas by an example of underground gasholder.
Materials and methods The material was sampled in 1998–2003 at the territory of underground gasholder located in Albeluvisol’s zone in Russia. According
to the comparative-geographical method, 51 soil profiles have been studied in similar litologically geomorphological conditions
in various geochemical zones: in the industrial zone, in the zone of gas dissipation, and at the regional background. The
total square of investigated territory is about 60 km2. Six soil profiles were investigated in seasonal dynamics. Samples of soils for physical, chemical, and microbiological analyses
were taken from each horizon of soil profiles (202 samples). Samples of soil air for a definition of methane concentration
were taken from depths of 20, 40, and 60 cm. Methane emission to the atmosphere was measured near soil’s cuts and, in addition,
on all area of the investigated territory at knots of squares network through 700–1,000 m, in total at 32–42 points in May,
July, and November. Years of investigation have been split by technological and hydrothermal conditions. The periods with
the normal and lowered compression of gas in gasholder, dry and warm, and damp and cool years have been allocated. It has
influenced the soil function processes and considered an interpretation of the data received.
Results The changes of functional parameters of soils at a gas-bearing area influenced by methane fluxes migrating from gas deposits,
in comparison with background soils, are revealed. Such functional parameters are methane concentration in the soils, activity
of its bacterial oxidation, methane emission to the atmosphere, and oxidation–reduction potential. Spatial and temporary dynamics
of these parameters at gas-bearing and background territory are investigated.
Discussion Methane interaction with soil’s air is in its ascending (descending) and lateral diffusion and convection in soils. Methane
fluxes dissipate in porous space of soils forming gas anomalies. The technogenic-allochthonous methane concentration strongly
varies in soil’s air on gas-bearing area (1–10,500 ppm) and, on average, exceeds the autochthonous, microbiologically produced
methane at background territories. Migratory methane is deposited on diffusion and sorption barriers. The capacity of diffusion
barrier depends on effective coefficient of diffusion, the attitude of air and general porosity, and granulometric composition
and sharply differs in auto-, semi-hydro-, and hydromorphic soils reaching maximum in hydromorphicity and among the soils
with identical water content—in heavy soils. The capacity of the sorption barrier is defined by abiotic methane absorption
and a specific surface of soils and grows with their increasing intensity in soils to a heavier granulometric composition
or into soils with peat and gleyic horizons. The low sorption capacity leads to an increase of methane concentration in the
soil’s air and decreases its utilization by microorganisms, in which its quantity depends on sorption properties. The central
component of functioning that promotes a number of essential transformations in soils on gas-bearing areas is methane interaction
with the biotic phase. The periods of methane deposition by diffusion and sorption barriers are used for biological methane
oxidation and formation of biogeochemical barriers in soils. The activity of bacterial methane oxidation is characterized
by spatial variability and depends on the entrance of methane, defined by granulometric composition, soil moisture, the attitude
of air and general porosity, Eh, organic matter content, and salinization. During interaction between technogenic-allochthonous
methane and soil on diffusion, sorption, and biogeochemical barriers, its transformation occurs, accompanied by a strengthening
of variability of oxidation–reduction potential and formation of pedogenic, bacteriomorphic, and nanodispersic magnetic oxides
of iron.
Conclusions and perspectives Specificity of soil functioning on a gas-bearing area is in interaction of technogenic-allochtonous methane with solid, liquid,
gaseous, and living substance of the soil system. Spatial laws of soils functioning on gas-bearing area in the Albeluvisol’s
zone are revealed. Distinctions of soil functions depending on litologically geomorphological conditions are shown. The greatest
changes of parameters of functioning under the influence of technogenic-allochthonous methane occur in automorphic soils,
and it is less in semi-hydromorphic soils. Activity of bacterial methane oxidation in soils, emission, and consumption from
the atmosphere and their spatial laws are characterized by the time dynamics depending on hydrothermal and technological conditions
of seasons and years. During oxidation in soils of gas-bearing areas, carbon of methane is concentrated on a biogeochemical
barrier that is shown in the increase of methylotrophic microorganisms’ biomass and leads to a high variability and decrease
of Eh and to the formation of magnetic oxides of iron.
Recommendations Results of research can be used for carrying out ecological monitoring and an estimation of tightness of objects of the gas
industry. Activity of bacterial methane oxidation, Eh, and magnetic oxides of iron can be used as diagnostic parameters of
soils on gas-bearing areas.
This paper has been developed from a presentation at the conference SUITMA-4 (Soils in Urban, Industrial, Traffic, Mining
and Military Areas) Nanjing, China, 2007 相似文献
32.
In this study the hydrological regime of Norway spruce (Picea abies) and birch (Betula pendula) growing on heavy soils in the south east of Austria was analysed. Results from the year 2003 characterised by an extremely hot and dry summer are presented in this paper. Due to the extreme weather conditions the soil water content in August 2003 was very low (0.10–0.25 m3 m−3) in the topsoil (0–50 cm) with no explicit difference between both tree species. 相似文献
33.
Variability with xylem depth in sap flow in trunks and branches of mature olive trees 总被引:1,自引:0,他引:1
Knowledge of sap flow variability in tree trunks is important for up-scaling transpiration from the measuring point to the whole-tree and stand levels. Natural variability in sap flow, both radial and circumferential, was studied in the trunks and branches of mature olive trees (Olea europea L., cv Coratina) by the heat field deformation method using multi-point sensors. Sapwood depth ranged from 22 to 55 mm with greater variability in trunks than in branches. Two asymmetric types of sap flow radial patterns were observed: Type 1, rising to a maximum near the mid-point of the sapwood; and Type 2, falling continuously from a maximum just below cambium to zero at the inner boundary of the sapwood. The Type 1 pattern was recorded more often in branches and smaller trees. Both types of sap flow radial patterns were observed in trunks of the sample trees. Sap flow radial patterns were rather stable during the day, but varied with soil water changes. A decrease in sap flow in the outermost xylem was related to water depletion in the topsoil. We hypothesized that the variations in sap flow radial pattern in a tree trunk reflects a vertical distribution of water uptake that varies with water availability in different soil layers. 相似文献
34.
Anastasia Frolova Nadezhda Aksenova Ivan Novikov Aitsana Maslakova Elvira Gafarova Yuri Efremov Polina Bikmulina Vadim Elagin Elena Istranova Alexandr Kurkov Anatoly Shekhter Svetlana Kotova Elena Zagaynova Peter Timashev 《Marine drugs》2021,19(12)
The growing applications of tissue engineering technologies warrant the search and development of biocompatible materials with an appropriate strength and elastic moduli. Here, we have extensively studied a collagenous membrane (GSCM) separated from the mantle of the Giant squid Dosidicus Gigas in order to test its potential applicability in regenerative medicine. To establish the composition and structure of the studied material, we analyzed the GSCM by a variety of techniques, including amino acid analysis, SDS-PAGE, and FTIR. It has been shown that collagen is a main component of the GSCM. The morphology study by different microscopic techniques from nano- to microscale revealed a peculiar packing of collagen fibers forming laminae oriented at 60–90 degrees in respect to each other, which, in turn, formed layers with the thickness of several microns (a basketweave motif). The macro- and micromechanical studies showed high values of the Young’s modulus and tensile strength. No significant cytotoxicity of the studied material was found by the cytotoxicity assay. Thus, the GSCM consists of a reinforced collagen network, has high mechanical characteristics, and is non-toxic, which makes it a good candidate for the creation of a scaffold material for tissue engineering. 相似文献
35.
Yespembetov Bolat A. Syrym Nazym S. Zinina Nadezhda N. Sarmykova Makhpal K. Konbayeva Gulshat M. Basybekov Sovetzhan Z. Mussayeva Assiya K. Kanatbayev Serik G. Bazarbayev Marat Siyabekov Sarsenbek T. 《Tropical animal health and production》2019,51(8):2361-2370
Tropical Animal Health and Production - The purposes of this study were to determine phenotypic and genotypic characteristics of Brucella isolates from the Republic of Kazakhstan and to determine... 相似文献
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Nadezhdina N 《Tree physiology》1999,19(13):885-891
Night and especially predawn tree water status is an important indicator of drought stress in trees. Leaf water potential (LWP) is frequently used as a measure of tree water status and hence drought stress; however, there are difficulties associated with sampling foliage from tall trees and determining LWP automatically. The current study was undertaken to determine whether sap flow index (SFI), which can be automatically and continuously recorded even during very low flows, can be used to estimate drought stress in trees caused by dry air under non-limiting soil water conditions. We made simultaneous measurements of LWP, heat pulse velocity (HPV) and SFI on apple trees (Malus domestica Borkh.) in the semiarid climate of southern Ukraine over several growing seasons. Predawn values of LWP were highly correlated with SFI. Over the range of low sap flow rates occurring at nighttime, where other methods of measuring sap flow are not sensitive, the SFI method was linear and very sensitive. Additional information about tree water status was obtained by comparing nighttime and daytime values of SFI. The ratio of predawn SFI to midday SFI and the period between the two daily SFI maxima (the first SFI peak occurred in the morning and the second peak occurred in the evening on cloudless days) can be used to characterize internal plant water balance. Although the daily course of SFI was variable, specific patterns were identified that reflected particular stages in the development of plant drought stress. An "air-drought-stress curve" was used to characterize the development of water stress in trees subjected to air drought during the growing season. 相似文献
39.
Kim HJ Graham DW DiSpirito AA Alterman MA Galeva N Larive CK Asunskis D Sherwood PM 《Science (New York, N.Y.)》2004,305(5690):1612-1615
Siderophores are extracellular iron-binding compounds that mediate iron transport into many cells. We present evidence of analogous molecules for copper transport from methane-oxidizing bacteria, represented here by a small fluorescent chromopeptide (C45N12O14H62Cu, 1216 daltons) produced by Methylosinus trichosporium OB3b. The crystal structure of this compound, methanobactin, was resolved to 1.15 angstroms. It is composed of a tetrapeptide, a tripeptide, and several unusual moieties, including two 4-thionyl-5-hydroxy-imidazole chromophores that coordinate the copper, a pyrrolidine that confers a bend in the overall chain, and an amino-terminal isopropylester group. The copper coordination environment includes a dual nitrogen- and sulfur-donating system derived from the thionyl imidazolate moieties. Structural elucidation of this molecule has broad implications in terms of organo-copper chemistry, biological methane oxidation, and global carbon cycling. 相似文献