SYNOPSIS. Shale oil retort water is obtained by centrifuging the oil/water emulsion produced by oil shale retorting. The ciliate Tetrahymena pyriformis was exposed to retort water; 2, 1, and 0.5% initially increased motility; longer exposures decreased motility. Three, 4, and 5% all decreased motility. Cell lysis was directly related to concentration; after 24 h, population densities were 0, 10, and 25% of controls for 2, 1, and 0.5% retort water, respectively. Oxygen consumption paralleled the motility pattern: at lower concentrations it increased initially but decreased with extended exposures while at higher concentrations it decreased rapidly. The most striking cytologic alteration of cells exposed to the toxicant occurred in the membranes; alterations of mucocysts and glycogen content were also observed, but mitochondrial changes were not. Population growth was affected at much lower concentrations than the other test indices. The growth of test populations reached a plateau at values inversely related to concentration: concentrations <0.4% had no effect on growth rate. 相似文献
The aim of the present study was to design and test a method allowing the detection and quantification of methanogenic consortia in organic‐rich rocks to determine the potential of methane biotransformation.
Methods and Results
Methanogen numbers in the rock are often below the detection levels of quantification methods. Biostimulation was tested as a means to specifically increase bacterial and archaeal numbers above the detection levels in microcosms. Biostimulation reveals the presence of active heterotrophic and syntrophic bacterial consortia, methane accumulation and methanogens in one of four rock samples. Syntrophs and heterotrophs were dominated by Firmicutes, whereas archaeal diversity was limited to methanogens. Methane‐producing microcosms were characterized by a higher Firmicutes diversity.
Conclusions
Biostimulation is a reliable tool for detection of methanogenic consortia in organic‐rich rocks. For routine and large scale experimentation, methane accumulation monitoring after biostimulation appears as the most time, work and cost efficient approach to detect the presence of active methanogenic consortia.
Significance and Impact of the Study
We report for the first time the presence of live methanogenic consortia in organic‐rich shales and their ability to mineralize the rock into methane. This approach will be instrumental to quantify the potential of these rocks to produce methane as a novel energy source. 相似文献
The upper Ordovician succession of Jordan was located 60°S, less than 100 km from the Hirnantian ice sheet margin. New graptolite dates indicate glaciation ended in Jordan in the late Hirnantian (persculptus Biozone). The succession records two glacial advances within the Ammar Formation and the subsequent deglaciations. Organic-rich black shales (Batra Formation) form part of the final deglacial transgressive succession that in-filled an existing low stand glacial continental shelf topography. The base of the black shale is coincident with the maximum flooding surface. During transgression, interfluves and sub-basin margins were breached and black shale deposition expanded rapidly across the region. The top of the black shales coincides with peak highstand. The “expanding puddle model” (sensu Wignall) for black shale deposition, adapted for the peri-glacial setting, provides the best explanation for this sequence of events.
We propose a hypothesis in which anoxic conditions were initiated beneath the halocline in a salinity stratified water column; a fresher surface layer resulted from ice meltwater generated during early deglaciation. During the initial stages of marine incursion, nutrients in the monimolimnion were isolated from the euphotic zone by the halocline. Increasing total organic carbon (TOC) and δ13Corg up section indicates the organic carbon content of the shales was controlled mainly by increasing bioproductivity in the mixolimnion (the Strakhov model). Mixolimnion nutrient levels were sustained by a continual and increasing supply of meltwater-derived nutrients, modulated by obliquity changes in high latitude insolation. Anoxia was sustained over tens to hundreds of thousands of years. The formation of black shales on the north Gondwana shelf was little different to those observed in modern black shale environments, suggesting that it was the nature of the Ordovician seas that pre-disposed them to anoxia. 相似文献
Pollution from the oil shale dump in Maoming, Guangdong Province, China, was a major social problem due to the great amount of environmental damage it caused. Therefore, a great deal of attention needed to be paid for the ecological restoration and reconstruction. The objective of this study was to investigate the species composition of soil fauna and its diversity in oil shale dumps after the application of different ecological restoration schemes in order to understand the impact they had on ecological restoration. Three plots were selected on an oil shale dump near the city of Maoming. The “north plot” was a newly-planted young forest mixed with various tree species, while the “south plot” was a 20-year-old Acacia auriculaeformis forest, and the “control plot” was a 20-year-old naturally-recovering grassland. Soil animals, mainly including macro-meso groups, were collected by hand-sorting and Tullgren funnel extraction. They were then identified to family or genus level with only a small portion to order (e.g. Chllopoda) or species (e.g. Isopoda) level. The specimens obtained in the present study was 11164 individuals, belonging to 27 orders and 110 families or genera. The Shannon index (H′), DGs (based on species) and DGg (based on groups) were used to analyze the diversity of soil animals between different plots. The major results were as follows: A total of 33 families or genera belonging to nine orders were found in the “north plot”. The main group was Caritermes, accounting for 63.4% of the total, followed by Tetramorium with 21.3%. Hymenoptera, mainly Formicidae, had more genera than others, accounting for 80% of the total genera in this group. The diversity of soil animals in this plot was very low because the H′ index was only 1.2, while the DGs index was 4.0 and the DGg index was 1.3. A total of 61 families or genera belonging to 23 orders were found in the “south plot”. Malmcoangelia and Tetramorium were the main groups, which accounted for 60.3% and 10.2%, respectively. Two genera of Annelda and two genera of Isopoda only accounted for 2.6% and 1.9%, respectively, but they were considered to be major groups due to their large body sizes and the distinct characteristics of their habitat. Acarina had a greater number of individuals and families or genera with its individual number accounting for 67.5% of the total, and the number of families or genera of this group account for 70% in this plot. The diversity indexes (H′, DGs and DGg) in this plot were significantly higher than those in the “north plot”, and were 1.65, 16.7 and 7.75, respectively. In the “control plot”, there were 67 families or genera of soil animals belonging to 23 orders. The main groups were Tetramorium (20%), Lasius (17.1%), Bothriomymex of Formicidae (13.8%), and Malmcoangelia of oribatid mites (14.5%). Formicidae of Hymenoptera was the group with the maximum number of individuals, accounting for 51.0%, while Diplopoda had the most families or genera. The H′ and DGs indexes, being 2.54 and 17.7, were higher than those in the “south plot”, while the DGg index of 7.20 was lower than that in the “south plot”. The results showed that the species composition and diversity indexes were higher in the “south plot” than in the “north plot” and the “control plot”, which demonstrated that using Acacia auriculaeformis forest to restore the oil shale dump was an effective approach in terms of soil biodiversity. 相似文献
In the process of shale gas fracturing, long time, high strength, and boring task could trigger psychological or physical operation fatigues, and then lead to downtime, sand blocking, or other accidents, which are the main problems in safety management. However, conventional studies either separately analyze risks without considering the interaction and relationship between humans or teams, or only form a qualitative framework for team analysis. These methods cannot be directly applied for the fracturing operators due to complex operation procedures and diversified human errors. An improved methodology, therefore, is proposed to assess human holistic risk during the whole cycle of fracturing operation. First, D-S evidence theory is introduced to obtain the individual risk, and team performance shaping factor is also presented to establish risk assessment model for fracturing teams. Second, individual and team risks are integrated to calculate the quantitative value of human holistic risk. A scatter diagram of human risk is finally designed, where the high-risk fracturing stages and human types can be clearly revealed. Results from a study of one shale gas well indicate that human holistic risk is more objective and practical, and improves accuracy of human reliability analysis. 相似文献
A study was conducted to evaluate the long‐term effects of biosolids amendment on restoration of disturbed sagebrush steppe habitat in northwestern Colorado. Twenty‐four years after biosolids amendment, soil fertility and plant community development were studied in replicated plots receiving various biosolids amendments on two different substrates. The two substrates used were a subsoil, determined to have low initial fertility, and a topsoil over retorted shale substrate, determined to have relatively high initial fertility. Results suggest that biosolids amendments have long‐lasting effects on soil fertility and plant community composition, but these effects vary between the two substrates that were utilized. Within the plots established on subsoil, the long‐term effect of biosolids was a reduction in plant species diversity and dominance by perennial grasses. On the topsoil substrate, there was a decrease in perennial grasses and an increase in shrub dominance with increasing biosolids. Results demonstrate the importance of considering initial soil conditions, seed mixture, and biosolids application rate when using biosolids for restoration of disturbed sagebrush steppe habitat. The long‐term effects of the biosolids treatments at this site demonstrate the need to consider restoration treatment effects over longer and more ecologically meaningful time frames. 相似文献