共查询到20条相似文献，搜索用时 31 毫秒
1.
Data on the morphology and radiocarbon ages of humus of dark vertic quasigley nonsaline clayey soils with alternating bowl-shaped (Pellic Vertisols (Humic, Stagnic)) and diapiric (Haplic Vertisols (Stagnic, Protocalcic)) structures are discussed, and the genetic concept for these soils is suggested. The studied soils develop on loesslike medium clay in the bottom of a large closed depression on the Eisk Peninsula in the lowest western part of the Kuban–Azov Lowland. The lateral and vertical distribution of humus in the studied gilgai catena displays a lateral transition of a relatively short humus profile of the accumulative type with a maximum near the surface and with a sharp increase in 14C dates of humus in the deeper layers within the diapiric structure to the extremely deep humus profile with a maximum at the depth of 40–80 cm, with similar mean residence time of carbon within this maximum, and with a three times slower increase in 14C dates of humus down the profile within the bowl-shaped structure. The development of the gilgai soil combination is specified by the joint action of the lateral–upward squeezing of the material of the lower horizons from the nodes with an increased horizontal stress toward the zones a decreased horizontal stress, local erosional loss of soil material from the microhighs and its accumulation in the adjacent microlows, leaching of carbonates from the humus horizons in the microlows, and the vertical and lateral ascending capillary migration of the soil solutions with precipitation of calcium carbonates in the soils of microhighs. 相似文献
2.
《European Journal of Soil Biology》2008,44(2):198-201
The term domicole, derived from the Latin domus (house) and colere (to inhabit), applies to species that are able (or adapted) to live in urban dwellings. Examples of domicole species include, for example, Psocoptera (dust lice) and Arachnida (spiders). However, so far, no earthworm species has been described as being capable of adapting to this type of niche. It seems, however, that the tropical species Dichogaster bolaui (Michaelsen, 1891) might be the first earthworm species to be defined as a domicole species.D. bolaui is native to eastern Africa. However, it has a wide distribution in tropical and subtropical regions. Additionally, it has been recorded in greenhouses in temperate countries and has also been observed in bathtubs and toilet bowls in Finland and Sweden. We collected data regarding the abundant presence of this species in bathtubs, showers, and sewer pipes in a student dormitory in Szombathely, Hungary, and in a private house in Haifa, Israel. Our data suggest that D. bolaui independently colonized the sewerage systems several times and established breeding populations and, therefore, has become a domicole. 相似文献
3.
Janet Mitchell 《Biological conservation》1976,9(1):25-28
Growth layers in the dentine of about 75 dugong, Dugong dugon (Müller), unworn permanent incisor teeth have been examined with a view to absolute age determination. Thirteen of these teeth come from complete skulls which had previously been allocated relative ages within three arbitrary life stage groups (Mitchell, 1973). The layer numbers found range from zero to , with a continuous scatter between the two extremes. It appears that the layers are either annual or biannual, and it is suggested that the dugong can attain an age of just under 60 or just under 30 years and reaches sexual maturity at about 10 or 5 years. A full account of this work is in preparation. 相似文献
4.
Eurasian Soil Science - Clay minerals are regarded as the most critical chemical and weathering components in ground. To establish the origin and distribution of the clay mineral associations of... 相似文献
5.
《CATENA》2004,58(1):23-40
Clays on the steep slopes of a small artificial sedimentary basin (sandpit quarry) alternately desiccate/crack and erode during hot dry and rainy seasons, respectively. Small irregular blocks of clay (IBC) predefined by cracks are released by gully erosion. The IBCs are quickly transported to the slope base and then rolled down the basin bottom by runoff. Due to rotation about a randomly changing axis and under an effect of deformation forces, the IBCs are transformed into spherical clay balls (SCB). The SCBs are transported, in general, towards the depositional base where they are buried by assorted sandy/clayey sediment. As soon as the kinetic energy of the runoff has decreased, the SCBs remain spread along transport path. From their distribution, the shaping process was evaluated. Based on data processing, the dependency,relating the clay ball projection sphericity, ψ, to the effective diameter, def, and to the distance from the steep slope base, λ, was found. Based on this equation, the length of clay ball transport can be estimated if the projection sphericity and effective diameter are known. 相似文献
6.
A battery of eight biomarkers was used on the freshwater bivalve Dreissena polymorpha in order to evaluate potential sub-lethal effects of the nonsteroidal anti-inflammatory drug diclofenac (DCF; 2-[(2,6-dichlorophenyl)amino]phenylacetic acid). By an in vivo approach, mussels were exposed for 96 h to increasing concentrations (0.3, 1, and 2 nM) of DCF perfectly comparable with current surface water levels. We determined the single cell gel electrophoresis assay, the apoptotic frequency (DNA Diffusion assay), the micronucleus test (MN test), and the lysosomal membrane stability (Neutral Red Retention Assay) in mussel hemocytes. Moreover, the activity of catalase, superoxide dismutase, glutathione peroxidase, and the phase II detoxifying enzyme glutathione S-transferase was measured in the cytosolic fraction extracted from a pool of entire bivalves to reveal possible alterations of the oxidative status of exposed specimens. The biomarker battery pointed out a negligible cyto- and genotoxicity on zebra mussel hemocytes since only a slight decrease of lysosomal membrane stability from baseline levels was measured at the end of exposures at the highest concentration (2 nM). In addition, environmental concentrations of DCF seem to have a negligible effect on the activities of antioxidant and detoxifying enzymes. 相似文献
7.
8.
Mariusz Czop Jacek Motyka Ondra Sracek Marek Szuwarzy��ski 《Water, air, and soil pollution》2011,214(1-4):423-434
The Gorka pit lake was formed in an inactive Jurassic limestone quarry after cessation of open-pit dewatering. The main problem of the water quality in this area is linked to a large volume of extremely alkaline leachate disposed in the flooded quarry. The lake is meromictic due to a large density contrast between shallow and deep water layers. Water in the lake is of the Na?CCO3?COH type, pH is in the range from 11.5 to 13.3, and there are high concentrations of sulfate and several toxic elements (Al, As, Cr, Mo, P, and V). The chemical composition of the extremely alkaline leachate was formed as a result of the groundwater interaction with the industrial red mud wastes containing 5?C10 wt.% of sodium carbonate. There is a trend of increasing concentrations and pH values with depth, mainly due to the in-gassing of atmospheric CO2 into the surface layer and due to density stratification in the water column. Similar stratification is observed in groundwater wells around the lake. High dissolved concentrations of oxyanionic contaminants such as As, Cr, and V are caused by their high mobility and desorption under extremely alkaline conditions. In spite of reducing conditions at the bottom of the lake, caused by high concentrations of dumped organic matter, sulfate behaves conservatively because sulfate reducing bacteria do not survive in this pH range. 相似文献
9.
Gold mining is the principal polluting activity in themunicipality of Poconé at the northern limit ofthe Pantanal of Mato Grosso, Brasil and ischaracterized by the inadequate use of mercury in thegold extraction process. A way to contribute to theassessment of the environmental impact of mercuryrelease in the Pantanal is to make use of bioaccumulation. Thus, determinations of total mercuryin 188 Gastropods of three different species were madein seven different sampling sites during the dry andwet periods. Increase of mercury levels in the snailswas restricted to the gold mining area and adjacentsedimentation areas. The largest mercuryconcentrations were found at the Tanque dos Padressite, reaching 2.04 g g-1 in individuals ofPomacea scalaris. In the other sampling sites,molluscs collected in the Araras/Piuval Bay complex,a mercury retention area, showed the largest mercuryconcentration, reaching up to 1.12 g g-1. 相似文献
10.
The salinization process was investigated with hydrogeochemical tools to evaluate the origin of salinity in the Selçuk Plain. Na/Cl and Cl/Br molar ratios of coastal zone that covers an alluvial aquifer, karstic discharges, and a wetland are similar to the local seawater ratio. According to mixing ratios, seawater addition can reach 9–18% in both seasons at the coastal zone especially in karstic springs that are a kind of seawater–freshwater mixing points. A thematic map of the Salinization zone was constructed for the Selçuk Plain using geographical information system tools with different parameters such as major ion ratios, EC values, mixing ratios, and sodium adsorption ratio values. High correlation between Cl and Br, B, Li and Sr explains the salinization process that comes from marine intrusion. The δ 18O and δD composition of water samples varies between ?6.7‰ and ?2.9‰; ?37‰ and ?20‰, respectively. The coastal zone waters are plotted on the mixing line due to the effects of the salinization process in the plain. 相似文献
11.
A. Martin 《Biology and Fertility of Soils》1991,11(3):234-238
Summary This study aimed to establish the effects of Millsonia anomala, a tropical geophagous earthworm common in the humid savannas of Lamto (Ivory Coast), on soil organic matter dynamics over different time scales under laboratory conditions. The texture of casts produced by the worms fed on a shrub savanna soil was not significantly different from that of the soil, which showed that M. anomala ingested soil particles without selection. Physical fractionation of soil organic matter showed that the coarse organic fraction (250–2000 m) was depleted by 25–30% in fresh casts compared to the control noningested soil; this was mainly due to a fragmentation of coarse organic debris. Incubation of casts and a 2-mm sieved control soil under laboratory conditions for more than 1 year showed that the C mineralisation rate was almost four times lower in the casts (3% year-1) than in the control soil (11% year-1). We therefore concluded that on a long time scale M. anomala populations may significantly reduce the decomposition rate of soil organic matter in Lamto savannas. 相似文献
12.
13.
14.
Avelar W. E. P. Mantelatto F. L. M. Tomazelli A. C. Silva D. M. L. Shuhama T. Lopes J. L. C. 《Water, air, and soil pollution》2000,118(1-2):65-72
Heavy metal levels were determined in marine mussels Perna perna collected from Ubatuba Bay, northern coast of the State of SãoPaulo, Brazil, during the period from January toOctober 1995. The objective of the present study wasto analyze the seasonal concentrations of some metalsof toxicological interest (Cd, Cu, Cr, Pb and Zn) inUbatuba Bay using the bivalve Perna perna(Linnaeus, 1758) as a biological monitor. Collectionswere performed at three month intervals at Itaguábeach. In the laboratory, the frozen specimens werethawed at room temperature, removed from their shells,partially dried on filter paper, weighed andindividually submitted to acid digestion with sulfuricacid and hidrogen peroxide. The analyses for thedetection of Cd, Cu, Cr, Pb and Zn were carried out byflame atomic absorption spectrophotometer. The resultsshowed higher metal accumulation during July. Thevalues detected for Pb and Cr were relatively high inall seasons, especially in January and July (vacationperiods) in Ubatuba Bay, with the consequent risk ofcontamination by mussel ingestion for the localpopulation and for tourists from other regions. 相似文献
15.
T. S. Demkina A. V. Borisov V. A. Demkin T. E. Khomutova T. V. Kuznetsova M. V. El’tsov S. N. Udal’tsov 《Eurasian Soil Science》2017,50(7):791-804
Diagnostic features of a catastrophic aridization of climate, desertification, and paleoecological crisis in steppes of the Lower Volga region have been identified on the basis of data on the morphological, chemical, and microbiological properties of paleosols under archeological monuments (burial mounds) of the Middle Bronze Age. These processes resulted in a certain convergence of the soil cover with transformation of zonal chestnut (Kastanozems) paleosols and paleosolonetzes (Solonetz Humic) into specific chestnut-like eroded saline calcareous paleosols analogous to the modern brown desert-steppe soils (Calcisols Haplic) that predominated in this region 4300–3800 years ago.1 In the second millennium BC, humidization of the climate led to the divergence of the soil cover with secondary formation of the complexes of chestnut soils and solonetzes. This paleoecological crisis had a significant effect on the economy of the tribes in the Late Catacomb and Post-Catacomb time stipulating their higher mobility and transition to the nomadic cattle breeding. 相似文献
16.
Effect of 2(N‐morpholino)ethane)sulfonic acid (MES) on the growth and tissue composition of cucumber
The effect of 2(N‐morpholino)ethane)sulfonic acid (MES) on the growth of cucumber (Cucumis sativa L. var. Marketer) in hydroponic culture was determined at 0, 1, 5, and 10 mM concentrations. The effect of adding the MES to the solution at the time of transfer to hydroponic culture or waiting one week was also determined. MES was observed to strongly affect plant growth with increasing concentration in nutrient solution. Tissue and nutrient solution analysis determined that MES affects manganese (Mn) uptake. MES appears to be reduced by Mn, precipitating the Mn out of solution. The suitability of MES as a pH buffer in hydroponic culture is discussed in terms of this effect. 相似文献
17.
《CATENA》2002,47(2):151-173
The area of the Jacupiranga Alkaline Complex and its surroundings is characterized by a variety of slope forms. Their spatial differentiation and the differences in relative relief and hilltop heights are a function of lithology. Significant contrasts exist, particularly between the ultramafic rocks of the Alkaline Complex and the quartz-rich rocks of the surrounding Precambrian basement. Although climatic conditions are uniform, the physical and chemical properties of the weathering products formed on the various rock types are very different. Through their properties, they affect the hillslope processes and thereby influence the hillslope development. Slope-forming processes on deeply weathered ultramafic rocks are slow mass movements and chemical denudation. On the more resistant ultramafic rocks, wash processes appear to be more important. Wash and rapid mass movements predominate on gneisses, granites and mica schists.The geomorphological development of the Jacupiranga Alkaline Complex can be explained in terms of a long, continuous downwearing. The large differences in elevation within the Alkaline Complex suggest that the development towards a more differentiated relief may extend well back into the Tertiary. The mutual adjustment of slope forms, processes and lithological controls favoured the development of rock-dependent summit heights, where heights are determined by the steepness of the slopes and the spacing of the drainage lines. Climatic fluctuations in the Pleistocene failed to produce any fundamental change in the long-term development of the hillslopes as their duration was too short with respect to the relaxation time of the hillslopes or their influence was not great enough to alter the overall trend of slope development. 相似文献
18.
19.
Khalil Rezaei Bernard Guest Anke Friedrich Farajollah Fayazi Mohamad Nakhaei Seyed Mahmoud Fatemi Aghda Ali Beitollahi 《Journal of Soils and Sediments》2009,9(1):23-32
Background, aim, and scope
The rapid growth of the world’s population over the past few decades has led to a concentration of people, buildings, and infrastructure in urban areas. The tendency of urban areas to develop in sedimentary valleys has increased their vulnerability to earthquakes due to the presence of soft soil and sediment. Several earthquakes have clearly demonstrated that local soil and sediment conditions can have a significant influence on earthquake-induced ground motion and damage pattern, respectively. Many studies confirm the relationship between site effect and ground motion (Borcherdt in Bull Seismol Soc Am 60:29–61, 1970; Bouckovalas et al. in Geotech Geolog Eng (Historical Archive) 14(2):111–128, 1996; Fäh et al. in Seismology 1:87–10, 1997; Atakan et al. in Nat Hazards 15(2–3):139–164, 1997; Christaras et al. in Geodynamics 26(2–4):393–411, 1998; Raptakis et al. in Bull Earthquake Eng 2(3):285–301, 2004a; Raptakis et al. in Soil Dyn Earthq Eng 25:871–887, 2005; Marka et al. in Pure Appl Geophys 158:2349–2367, 2001; Marka et al. in Soil Dyn Earthq Eng 25(4):303–315, 2005; Importa et al. in Seismology 9(2):191–210, 2005; Tyagunov et al. in Nat Hazards 38:199–214, 2006; Lombardo et al. in Nat Hazards 38:339–354, 2006; Rayhani et al. in Geotech Geol Eng 21(1):91–100, 2008). In order to classify the suitability of the soil and subsurface sediment units for urban planning and compare their mechanical behavior with the non-uniform damage observed in the 2003 earthquake, we performed some geotechnical and geophysical analyses of soil and sediment samples collected from different locations in Bam City.Methodology
Geophysical and geotechnical properties, such as grain size distribution, sorting, plasticity, Poison’s ratio, shear strength, compression index, permeability, and P and S wave velocities in soil and subsurface sediments, were measured. Maps (in GIS environment) and cross-sections were prepared for the study area.Results
According to our observations, a great number of buildings were damaged in areas of the city where silty and clayey soils dominate, presenting very low permeability, low wave velocity together with high plasticity, and compressibility. In the study area, we recognized eight sediment types. Shear wave propagation velocities allowed for the identification of four seismic layers referred to as the surface layer, second layer, and third layer and seismic bedrock. We found that the damages observed in the Bam area were related to the physical and mechanical properties of the soil and subsurface sediment units. We also found that the soil thickness that was estimated by geophysical surveying shows a direct relationship with damage rate observations. Furthermore, we observed that landslide and qanat collapses have occurred in some areas where sand and silty sand soils and subsurface sediments dominate.Discussion
The distribution of the damage shows a microzonation that is very serious in some points in the city along the main fault, especially where it is located on thick, fine, medium, and loose soil and sediments. In general, there is a discernable west to east increase in the damage across the city. The average level of destruction for the entire city was ~75%, while the eastern part of the city locally reached 100% destruction level. The major factors that influenced the damage and destruction in the Bam region were the distance of a given site from the seismic source, the quality of foundation soil and subsurface sediment, and the type of building. The Bam earthquake occurred on a single fault network comprising the Bam and Arg-e-Bam faults (Funning et al. in J Geophys Res 100(B09406):1–23, 2005). The sediments and soil of the area (unconsolidated silty sand and sandy gravel) belong to braided fluvial and alluvial facies. Most of the buildings near the epicenter area were old and constructed of mud bricks using mud cement.Recommendations and perspectives
A combined sedimentological, geological, neotectonic, geotechnical, paleoseismological, and geophysical investigation in urban areas (especially in alluvial valleys) will give the detailed knowledge of the subsurface structure required for the accurate and precise seismic hazard assessments needed for effective earthquake protection planning. This paper shows that for the Bam situation, sedimentological data are required to provide an interpretive context for the geophysical data. 相似文献20.