Monoterpene concentrations in fresh,senescent, and decaying foliage of singleleaf pinyon (Pinus monophylla Torr. & Frem.: Pinaceae) from the western Great Basin

Senescent foliage from pines is potentially a large contributor to the total monoterpene content of the litter layer, and the availability of these compounds as phytotoxins may result from release of these compounds into the vapor phase. In order to determine the fate of several monoterpene hydrocarbons in the natural environment, we examined their concentrations in fresh, senescent, and decaying needles from 32 single-leaf pinyon pine (Pinus monophylla Torr. & Frem.: Pinaceae) trees growing at two different locations. Total monoterpene content was highest in the fresh needles (mean=5.6 ± 2.2 mg/g extracted air dry weight), but also remained relatively high in senescent needles (mean=3.6 ±1.8 mg/g extracted air dry weight), either still attached to the tree or forming the freshest layer of understory litter. Decaying needles within a dark decomposing layer of litter material 5–20 cm from the surface were found to contain much lower amounts of total monoterpenes (average: =0.12 ±0.06 mg/g extracted air dry weight). Further investigation of the fate of these compounds in the pinyon understory is required to determine if these hydrocarbons are indeed exerting phytotoxic characteristics.     

Microorganisms and Cellulose Digestion in the Gut of the Woodlouse Porcellio scaber

In the common woodlouse Porcellio scaber different parts of the gut were observed with respect to microbial counts, cellulose activity, and degradation of cellulose. Cellulose is mainly digested in the anterior part of the hindgut, as was indicated by the distribution of cellulolytic activity and the decrease of cellulose content inside the gut. The cellulases woodlice utilize for the degradation of litter are mainly produced by endosymbiotic bacteria in the hepatopancreas rather than by microorganisms ingested with the food. Microorganisms ingested with the litter are digested in the anterior part of the hindgut and may provide an important food source. In the posterior hindgut, bacterial proliferation ensures microbial colonization of feces.     

电梯不同负载下的功能设置

围绕电梯负载时的功能设置命令编制 ,针对电梯不同负载情况设定相应的功能 ,使电梯的运行更加科学、合理、有效。     

Nitrogen budget for fescue pastures fertilized with broiler litter in Major Land Resource Areas of the southeastern US

The southeast US produces a tremendous number of broiler chickens (Gallus gallus), which in turn produce massive quantities of litter (manure and bedding materials). In the Southeast, litter is most often disposed of via land application to pastures, however, the ultimate fate of much of the applied nitrogen (N) is not known. We have constructed N budgets for three sites across the southeastern U.S. in an effort to determine how much of the applied N is useful for plant production and how much is left to be absorbed by the environment. Study sites were located in the Coastal Plain (Alabama), Piedmont (Georgia), and Cumberland Plateau (Tennessee) Major Land Resource Areas (MLRA) of the southeastern US. Litter was applied in the Spring of two consecutive years at a rate to supply 70 kg of available N ha^–1. The total amount of N applied ranged from 103 to 252 kg N ha^–1 depending on site and year. Nitrogen fluxes monitored in this study were broiler litter N, ammonia (NH₃) volatilization, denitrification, plant uptake, and leaching. Plant uptake represented the largest flux of applied N, averaging 43% of applied N. Losses due to NH₃ volatilization and denitrification combined were only 6% of applied N on average. Loss of N due to NO₃-N leaching appeared to be significant only at the Coastal Plain site where NO₃-N concentrations in the groundwater peaked at 38 mg N l^–1. We believe the majority of excess N shown in these budgets is likely accounted for by leaching losses and soil accumulation. Regardless of these assumptions and low gaseous losses, it is apparent that on average, 57% of applied N is destined for a fate other than plant uptake. The results of this study indicate that land-application of broiler litter at currently recommended rates has the potential for negative impacts on the environment of the southeastern U.S. in the long-term.     

Evaluation of basidiomycetous fungi for pretreatment of contaminated soil

BACKGROUND: For most dioxin‐contaminated sawmill soils, combustion is recommended. However, the process may be inefficient if the soil has a high organic matter content. The use of saprotrophic basidiomycetous fungi is an alternative for pretreatment of this kind of soil. A total of 147 fungi were evaluated for their ability to grow in sawmill soil. From this screening, the best soil colonizing fungi were selected to study their enzyme activities and degradation of soil organic matter. Pine (Pinus sylvestris) bark was used as a co‐substrate to propagate the fungi into the soil. The activities of manganese peroxidase (MnP), laccase, endo‐1,4‐β‐glucanase, endo‐1,4‐β‐xylanase, and endo‐1,4‐β‐mannanase were analysed from the inocula and fungal treated soil. RESULTS: The screening revealed that 56 out of 147 fungi were able to grow in non‐sterile soil, and most of them were litter‐decomposing fungi (LDF). In pine bark cultures, the highest enzyme activities were observed with Phanerochaete velutina, which produced 5 U g^?1 of MnP. The activity of endo‐1,4‐β‐glucanase was generally higher than that of other hydrolytic enzymes. The highest carbon loss from soil with a high organic matter content was achieved by P. velutina (3.4%) and Stropharia rugosoannulata (2.4%). CONCLUSIONS: Many LDF, and in addition the white‐rot fungus P. velutina, are potential degraders of soil organic matter since they showed good growth and respiratory activity. Pine bark was a suitable lignocellulosic co‐substrate and a good promoter of MnP activity. Copyright © 2009 Society of Chemical Industry     

红松林地表凋落物层燃烧数值模拟

采用PyroSim建立红松林地表凋落物层大空间模型,对凋落物层的燃烧温度、热释放速率、烟气浓度等进行数值模拟。取红松林地表凋落物进行试验,探究其燃烧与蔓延过程。结果表明,红松林地表凋落物层燃烧时温度在100～490 ℃;随着高度增加,温度下降幅度由剧烈逐渐趋于平缓;燃烧150 s时,热释放速率HRR达到7.5×105 kW,且有继续上升趋势;燃烧烟气中CO2体积分数达8％～10％;火场内流动风速为2 m/s时,烟气体积分数下降65％左右。凋落物燃烧温度曲线与模拟结果相似,采用PyroSim软件能够近似地模拟红松林地表凋落物层燃烧的过程与发展趋势。     

Effects of Land Use on the Composition and Structure of Aquatic Invertebrate Community and Leaf Breakdown Process in Neotropical Streams

Different land uses directly affect the characteristics of a river basin and influence the aquatic biota and ecosystem processes. This study aimed to analyse the community structure and composition of aquatic invertebrates and the role of these organisms in the process of leaf litter breakdown in streams with different land uses. The study was conducted from September to December 2013 in five streams in the Neotropical region. At each stream, we placed 18 bags containing litter for colonization by aquatic invertebrates, and the bags were collected at different exposure times (5, 30, 45, 60, 75 and 90 days). We registered spatial differences in the aquatic invertebrate community structure and composition. There were no significant differences in the activity of invertebrates in the leaf litter breakdown process among streams with different land uses. However, the variability in mass decay rate was lower for the reference stream. This result may have been influenced by habitat quality, availability of organic matter and the structure and composition of benthic community present in the reference stream, which differs significantly among locations with different types of land use. The results of this study shows that human activities, particularly agriculture and urbanization, modify the structure and composition of the benthic community and acts on ecosystem processes, especially in the variability of the processing of allochthonous material invertebrates. However, we reject the hypothesis that land use negatively influences the decomposition of litter, measured by weight loss. Copyright © 2016 John Wiley & Sons, Ltd.     

Effects of Elevated CO<Subscript>2</Subscript> and Herbivore Damage on Litter Quality in a Scrub Oak Ecosystem

Atmospheric CO₂ concentrations have increased dramatically over the last century and continuing increases are expected to have significant, though currently unpredictable, effects on ecosystems. One important process that may be affected by elevated CO₂ is leaf litter decomposition. We investigated the interactions among atmospheric CO₂, herbivory, and litter quality within a scrub oak community at the Kennedy Space Center, Florida. Leaf litter chemistry in 16 plots of open-top chambers was followed for 3 years; eight were exposed to ambient levels of CO₂, and eight were exposed to elevated levels of CO₂ (ambient + 350 ppmV). We focused on three dominant oak species, Quercus geminata, Quercus myrtifolia, and Quercus chapmanii. Condensed tannin concentrations in oak leaf litter were higher under elevated CO₂. Litter chemistry differed among all plant species except for condensed tannins. Phenolic concentrations were lower, whereas lignin concentrations and lignin/nitrogen ratios were higher in herbivore-damaged litter independent of CO₂ concentration. However, changes in litter chemistry from year to year were far larger than effects of CO₂ or insect damage, suggesting that these may have only minor effects on litter decomposition.     

Consumption and production waste: another externality of tobacco use

OBJECTIVE: To describe the waste produced by and environmental implications of individual cigarette consumption (filter tips, packages, and cartons) and tobacco manufacturing. STUDY SELECTION: All available articles and reports published since 1970 related to cigarette consumption and production waste were reviewed. DATA SOURCES: Global cigarette consumption data were used to estimate cigarette butt and packaging waste quantities. Data from the Center for Marine Conservation's International Coastal Cleanup Project were used to describe some environmental impacts of tobacco-related trash. Data from the United States Environmental Protection Agency's (EPA's) Toxics Release Inventory and reported global cigarette consumption totals were used to estimate waste production from cigarette manufacturing. DATA EXTRACTION AND SYNTHESIS: In 1995, an estimated 5.535 trillion cigarettes (27,675 million cartons and 276,753 million packages) were sold by the tobacco industry globally. Some of the wastes from these products were properly deposited, but a large amount of tobacco consumption waste ends up in the environment. Some is recovered during environmental clean-up days. For the past eight years (1990-1997), cigarette butts have been the leading item found during the International Coastal Cleanup Project; they accounted for 19.1% of all items collected in 1997. The tobacco manufacturing process produces liquid, solid, and airborne waste. Among those wastes, some materials, including nicotine, are designated by the EPA as Toxics Release Inventory (TRI) chemicals. These are possible environmental health hazards. In 1995, the global tobacco industry produced an estimated 2262 million kilograms of manufacturing waste and 209 million kilograms of chemical waste. In addition, total nicotine waste produced in the manufacture of reduced nicotine cigarettes was estimated at 300 million kilograms. CONCLUSIONS: Laws against littering relative to cigarette butts could be better enforced. Additional taxes might be levied on cigarette products that would then be directed to environmental clean-up efforts. The tobacco industry should improve the biodegradability of filters, reduce packaging waste, and educate its customers. Worksites and public buildings should be encouraged or required to supply appropriate disposal mechanisms at all building entrances. Public awareness campaigns about the magnitude and prevention of cigarette consumption waste could be developed through partnerships among environmental groups, health organisations, and environmental protection agencies. Tobacco production waste should be a source of concern and regulation by governments throughout the world; it contains numerous chemicals which may be considered health hazards, not the least of which is nicotine produced in the manufacture of low-nicotine cigarettes.     

膨润土/沸石制备猫砂实验研究

本文利用X射线(衍)射、SEM及化学分析等方法,研究了北票膨润土及沸石特性.通过实验研究,找出了沸石改性较好的试验条件,确定了膨润土与沸石的最佳配比,制备的猫砂产品比国内猫砂性能好,接近国外进口猫砂的性能指标.