甲基一六O五降解菌J5的分离及其降解性状研究

从农药厂污水处理系统中分离到 1株降解甲基一六O五 (O ,O-二甲基 -O- 对硝基苯基 -硫代磷酸酯 ,简称MP)的芽胞杆菌 ,初步鉴定为蜡状芽胞杆菌 (Bacilluscereus)J5。J5能够高效降解MP ,但它不能利用MP作为唯一碳源生长 ,其代谢方式可能为共代谢。在有葡萄糖作为碳源的条件下 ,J5可以高效转化MP ,其转化效率可达 95 %以上。用薄层层析、紫外扫描和液相色谱法初步研究了J5对MP的降解性能及相关降解产物     

Key Features and Context‐Dependence of Fishery‐Induced Trophic Cascades

Abstract: Trophic cascades triggered by fishing have profound implications for marine ecosystems and the socioeconomic systems that depend on them. With the number of reported cases quickly growing, key features and commonalities have emerged. Fishery‐induced trophic cascades often display differential response times and nonlinear trajectories among trophic levels and can be accompanied by shifts in alternative states. Furthermore, their magnitude appears to be context dependent, varying as a function of species diversity, regional oceanography, local physical disturbance, habitat complexity, and the nature of the fishery itself. To conserve and manage exploited marine ecosystems, there is a pressing need for an improved understanding of the conditions that promote or inhibit the cascading consequences of fishing. Future research should investigate how the trophic effects of fishing interact with other human disturbances, identify strongly interacting species and ecosystem features that confer resilience to exploitation, determine ranges of predator depletion that elicit trophic cascades, pinpoint antecedents that signal ecosystem state shifts, and quantify variation in trophic rates across oceanographic conditions. This information will advance predictive models designed to forecast the trophic effects of fishing and will allow managers to better anticipate and avoid fishery‐induced trophic cascades.     

Structure of pathways in ecological networks: relationships between length and number

In ecosystems network, structure determines adjacent (direct) and non-adjacent (indirect) pathways over which energy, matter, and information can flow. The more pathways, the more possible ways the conservative substance can move in zero-sum transactions between network nodes that the pathways interconnect, and the more possible non-conservative, nonzero-sum relations can be secondarily derived from these. Structural analysis is a tool we employ, from a family of input–output methods for exploring zero- and nonzero-sum attributes of environmental networks, to count pathways of varying length between network nodes. In this paper, we examine the relationship between pathway length (k) and number (P_k) as determined by system size (n, number of nodes) and extent and pattern of connectance (C). We develop a measure (m_a) of pathway growth in numbers with increasing length, and then normalize this to the maximum rate possible (m_a/m_c) for a given system size. These measures apply to two pathway types—paths, m_a(0) and m_a(0)/m_c(0), which forbid adjacent node repetitions, and walks, m_a(1) and m_a(1)/m_c(1), which allow them. We find that network size has a curvilinear effect on the pathway number versus length relationship, and extent and pattern of connectance are convolved. Values computed for the paths and walks of three ecosystem models (oyster reef, freshwater marsh, and reservoir cove) are used to compare their pathway structure.     

乌江干流中上游水电梯级开发水温累积效应

以乌江流域洪家渡库尾至乌江渡坝下的水电工程干扰典型段为研究区域，利用建坝前后的水温实测资料，采用建坝前天然水温和建坝后下泄水温比较法，对乌江干流梯级水库水温时空分布特征进行分析。研究结果表明：对天然水温改变最大的电站为洪家渡和乌江渡，前者是受水库水温结构自身影响，后者是梯级联合运行的结果；梯级联合运行使库区水温分层有所减弱，随着时间的推移或上游梯级电站的建成，电站下泄水温年变化过程趋于均化，与天然水温的延迟也越加明显；不同的水库水温结构对水温累积效应的影响也各不相同，稳定分层型水库对水温累积具有正效应，混合型水库具有负效应，过渡型水库处于两者之间，体现了梯级电站的水温累积影响，为研究减缓下泄低温水的对策措施提供依据和参考。     

Planning for Biodiversity: the Role of Ecological Impact Assessment

Abstract:  Environmental impact assessment (EIA) is the process of identifying potential environmental effects of proposed development and the required mitigation measures. It is one of the most widely used planning tools today, but its ability to promote biodiversity conservation is largely unexplored. We studied the ecological component of the Israeli EIA system by reviewing a representative sample of 52 environmental impact statements (EISs) produced since 1995 and their corresponding guidelines issued by the Ministry of the Environment. Quality of both EISs and guidelines was determined using a simple scoring approach. Lack of quantitative data, meaningful analyses, and ecosystem perspective was apparent throughout. Many EISs failed to perform field surveys and their qualitative nature hampered meaningful impact prediction. Most EISs concentrated on aesthetic mitigation measures and did not assess their feasibility and likely success. Most of these flaws reflect poor standards rather than true scientific limitations. Guideline quality scores were the most important factor determining the quality of EISs; second was the involvement of an ecological consultant in preparing the EIS. We found a decreasing trend of EIS quality scores over time. Improvements in EIA procedures, particularly in ecological guidelines and the incorporation of ecological consultation, are important for upgrading ecological impact assessment so that the potential of EIA to advance biodiversity conservation can be realized.     

Spillover of functionally important organisms between managed and natural habitats

Land-use intensification has led to a landscape mosaic that juxtaposes human-managed and natural areas. In such human-dominated and heterogeneous landscapes, spillover across habitat types, especially in systems that differ in resource availability, may be an important ecological process structuring communities. While there is much evidence for spillover from natural habitats to managed areas, little attention has been given to flow in the opposite direction. This paper synthesizes studies published to date from five functionally important trophic groups, herbivores, pathogens, pollinators, predators, and seed dispersers, and discusses evidence for spillover from managed to natural systems in all five groups. For each of the five focal groups, studies in the natural to managed direction are common, often with multiple review articles on each subject which document dozens of examples. In contrast, the number of studies which examine movement in the managed to natural direction is generally less than five studies per trophic group. These findings suggest that spillover in the managed to natural direction has been largely underestimated. As habitat modification continues, resulting in increasingly fragmented landscapes, the likelihood and size of any spillover effect will only increase.     

粉煤灰基质滤料生物过滤处理生活污水研究

将粉煤灰基质滤料用于曝气生物滤池,该滤料具有较高的比表面积和孔隙率,吸附性能良好,挂膜后生物相丰富。对于中等浓度的生活污水,当水力负荷和COD有机物负荷分别控制在1.53 m3/(m2.h)、3.68 kg/(m3.d)以下时,该曝气生物滤池COD和NH3-N去除率能稳定在85%以上,出水COD和NH3-N达到排放标准要求。该曝气生物滤池对进水水质水量的变动具有较强的抗冲击负荷能力。     

厌氧生物滴滤法脱除冷煤气中硫化氢的研究

水煤气中硫化氢在燃烧时会转变成二氧化硫,对环境产生污染。文章采用厌氧生物滴滤塔法对冷煤气进行脱硫处理。因煤气对氧的严格限制,通过设计生物滴滤塔,经挂膜驯化后在厌氧条件下对浓度在1~5 g/m3左右的硫化氢进行脱除处理,考察滴滤塔运行条件对脱除效果的影响。结果表明,生物挂膜25 d后,生物滴滤塔达到稳定,喷淋液pH值为2.23,ORP值为283 mV,溶解氧为0.4 mg/L,对溶液中硫离子氧化效率达到94%。滴滤塔在液气比0.15,空塔气速0.088 m/s,pH值5.0~7.0,填料高度为82 cm,塔温为25~30℃左右时,达到较优的运行条件,此时该滴滤塔对以CO、CO2、H2和1 940 mg/m3H2S组成的模拟水煤气的脱硫效率达91.2%。     

大气细颗粒物(PM_(2.5))在环境科学中的研究简述

细颗粒物作为一种重要的大气污染物,其形态与组成非常复杂,本身所具有的毒性和对环境的有害性已日益受到重视。文章对细颗粒物PM2.5在环境科学中的研究进行了概括,提出了自己的一些见解。     

单级和两级串联臭氧-生物活性炭深度处理垃圾渗滤液的比较研究

使用单级和两级串联臭氧-生物活性炭(O3-BAC)处理垃圾焚烧渗滤液的二级生物处理尾水,比较研究了污染物去除效果.结果表明,臭氧投加量为200 mg·L-1时,两级串联O3-BAC对COD、UV254和色度的去除率分别为75.9%±2.1%、78.8%±2.9%和96.8%±0.9%,处理出水COD基本保持在100 mg·L-1以下,色度低于40倍,满足GB 16889-2008排放要求;而单级O3-BAC对COD、UV254和色度的去除率分别为68.2%±1.3%、69.7%±0.5%和92.5%±1.1%,处理出水COD和色度分别为150 mg·L-1和60倍,不能达到排放要求.单级O3-BAC在290 mg·L-1臭氧投加量下,才能达到两级串联O3-BAC在200mg·L-1臭氧投加量下的污染物去除效果.此外,两级串联O3-BAC在臭氧投加量200 mg·L-1时的总磷去除率为63.5%±4.4%,出水总磷浓度稳定在1 mg·L-1以下,直接满足GB 16889-2008排放要求.