Trophic diversity in amphipods within a temperate eelgrass ecosystem as determined by gut contents and C and N isotope analysis

A conjoint analysis of gut contents and stable C and N isotopes was applied to determine the main food sources and feeding habits of dominant amphipods in an eelgrass bed (Zostera marina) in Gwangyang Bay, Korea. Gut content observations demonstrated that, while Gammaropsis japonicus and Jassa slatteryi are herbivorous, feeding on epiphytes and detritus, Pontogeneia rostrata and Monocorophium acherusicum are omnivorous, feeding on mesozooplankton fragments and detritus. Stable isotope data confirmed that epiphytes, detritus, and mesozooplankton fragments were major food sources for amphipods in the eelgrass bed. Isotopic mixing model calculations clearly showed an interspecific difference in diet composition. A high isotopic dissimilarity between amphipod taxa demonstrated interspecific trophic diversity, reflecting their herbivorous (G. japonicus and J. slatteryi) and omnivorous (P. rostrata and M. acherusicum) feeding habits and confirmed the detrivorous feeding habits of caprellids. Such trophic diversity at interspecific level of the amphipod species indicates that they use different food resources within their microhabitats and play species-specific functional roles as mediators in trophic pathways from producers to higher-level consumers of the eelgrass ecosystem. Finally, our findings suggest that information on the species-specific trophic ecology of amphipods is needed to better understand their potential role in the trophic dynamics and carbon flow of seagrass bed ecosystems.     

光催化膜反应器的设计及其在水处理中的应用

作为一种新型的水处理装置,光催化膜反应器具有反应迅速、降解效率高、降解彻底、无二次污染等特点,在节水减排、微污染水处理、中水回用等方面具有重要的应用价值。总结目前国内外各种不同类型的光催化膜反应器的设计、特点及在水处理中的应用情况,并对其今后的发展提出建议。     

基于Global-Malmquist-Luenberger指数的沿海地带陆海统筹发展水平测度及区域差异分析

沿海地区是陆海统筹发展的区域载体,基于沿海省市的陆海复合系统进行陆海统筹发展的区域评估对海洋强国建设的理论与实践具有重要意义。论文以陆海复合经济地域系统为前提,将沿海城市形成的区域作为沿海地带,基于各沿海城市的集合作为省级沿海地带进行比较分析,建立包括经济、社会、生态以及环境4个维度指标体系,在考虑“非期望”产出的情况下运用Global-Malmquist-Luenberger（GML）指数测算沿海地带陆海统筹发展水平并进行区域差异分析。结果表明：第一,总体上,沿海地带陆海统筹发展水平全要素生产增长率大多处于无效率状态,且不考虑非期望产出明显高估了全要素生产增长率的增长;时间上,陆域、海洋以及陆海综合GML指数的变动趋于一致,呈平稳的态势;效率分解,陆海统筹发展水平全要素生产率下降明显是由规模效率变动和技术规模变动的下降所影响。第二,沿海地带正经历从“重陆轻海”到逐步实现陆海统筹发展的过程;对沿海地带陆海统筹发展水平空间差异进行分类,浙江、福建及河北属于陆域效率驱动型,环渤海地区（除河北外）、江苏、广西和海南属于海洋效率驱动型,上海和广东属于陆海效率复合型;区域差异形成的原因主要有产业结构差异、海洋产业技术门槛、海洋资源承载力以及政府政策。     

脉冲电弧液相放电等离子体处理生活污水回用研究

利用脉冲电弧液相放电等离子体技术,采用某小区的生活污水,研究放电脉冲次数、放电峰值电压、曝气量对COD、氨氮去除的影响.随着放电脉冲次数的增加,COD与氨氮去除率逐渐升高,当放电脉冲次数为400次时,COD和氨氮的去除率分别为81.8％、80.3％.随着放电峰值电压的升高与曝气量的增加,COD、氨氮的去除效率增加.在相同放电处理时间下,当峰值电压为18 kV时,曝气量大于4m3/h,COD去除率大于96％,氨氮去除率大于90％,出水水质满足回用标准.     

A~2/O工艺在低温低浓度条件下处理效果及节能减耗研究

研究在低水温条件下,进厂污水中有机物浓度较低时(污水平均BOD5为45 mg/L左右),漳扎污水处理厂生化系统较优的运行工况。研究结果表明,在上述情况下,较优的连续运行工况为:污泥回流比为75%左右,MLSS为3 200~3 500 mg/L,生化池处的溶解氧在0.7~1.3 mg/L之间;较优的间歇运行工况为:以曝气3 h停曝3 h的方式运行,生化池处的溶解氧在3~5 mg/L之间,污泥回流比为75%左右,MLSS为3 200~3 500 mg/L。上述两种运行工况对污水中的污染物质都有较高的去除率,能成功避免污泥解絮的发生,使系统中的微生物平稳过冬;其中间歇曝气方式能达到节能减耗的目的,建议在旅游淡季时采用该方式运行。     

矿地复垦执行保证金的法治化问题研究

矿地复垦的市场调控失灵导致负外部性经济效果,政府命令与控制型因信息和寻租而同样失灵;保证金是弥补两个失灵时基于市场的政策工具,但要与矿地复垦协议共同使用。保证金的功能是担保矿地复垦合同的履行。复垦合同属行政管理中相对人自愿诺成行为,具有行政与民事的双重属性。行政机关的优益权和矿地验收决定等引起的争议属行政纠纷,救济要平衡合同主体双方,矿山利益和公共利益都要保护。这一切都要依靠理论研究、体制改革、培育中介机构等系列基础工程。     

土壤二维蒸气抽排去污效果的影响研究

土壤蒸气抽排是一种经济、高效、安全并已被广泛应用的污染场址现场修复技术,它能经济高效地去除非饱和带土壤中的挥发性有机污染物。以土壤和油污染物为例,进行了土壤二维抽排模拟实验,研究了气体抽排流量对去污效果的影响,通过实验可知:在增加气体抽排流量的情况下,抽排气中挥发性较强的有机物质正戊烷(C5h12)浓度下降的很快,最终保存在较低的浓度水平。挥发性一般的正辛烷(C8h18)和挥发性较弱的正癸烷(C10h22)经过长时间的抽排后,污染物也得到了降低,但是最终保持在比较高的浓度水平。得出增加气体抽排流量可以使污染物去除速率大幅度提高,从而缩短了净化时间,获得很好的去污效果。同时对二维抽排模拟实验和一维抽排模拟实验结果做了比较。     

地铁盾构施工风险评估与风险规避研究

深圳地铁二号线2202标段包括科苑站—红树湾站—世界之窗站,大部分采用盾构法施工。盾构隧道处于砂质粘性土地层填海地层,下穿4栋高尔夫别墅,存在基岩隆起、孤石和易出现施工扰动等情况。对2202标盾构施工进行安全评估,指出盾构机选型、盾构机进出洞及盾构施工过程中的风险源,如始发方向失控、盾尾卡死、洞口土体坍塌、地面建筑物出现不均匀沉降等,进而强调在施工过程中要正确辨识风险源,并根据地质、水文和周围环境条件研究采取适当的规避风险措施。     

基于安全社会学的高层建筑火灾事故剖析——以上海“11·15”特大火灾事故为例

结合我国基本国情及“11·15”特大火灾事故的具体情况,运用社会学视角,从技术和理性的局限、效益和安全的博弈、人因和制度的瓶颈三个方面透析由高层建筑火灾事故难以解决这一现状暴露出的社会学问题。并提出有利于从深层次上保障人民生命安全和公共财产安全的三点建议：调整引发不安全因素的社会结构;提升有利于确保安全的技术能力;加强政府的社会控制功能。本文针对我国高层建筑火灾事故频发的现状,揭示了“11·15”特大火灾事故带来的警示和反思,就高层建筑火灾防范提出了改进方法,对建筑、消防等部门的管理工作具有一定的参考意义。     

Assessment of elemental distribution and trace element contamination in surficial wetland sediments, Southern Tibetan Plateau

In order to analyze and evaluate different trace metals on surface water of the Changjiang River, concentrations of dissolved trace metals (Cu, Ni, Fe, Co, Sc, Al, Zn, Pb, Cd, Se, As, Cr, and Hg), major elements(Ca and Mg), and nutrient(NO $_{3}^{-})$ were measured. Samples were taken at 76 positions along Changjiang River in flood and dry seasons during 2007?C2008. Spatial distributions identified two main large zones mainly influenced by mineral erosion (sites 1?C22) and anthropogenic action (sites 23?C76), respectively. Principal component analysis (PCA) and hierarchical cluster analysis were used to identify the variance distinguishing the origin of water. Four significant components were extracted by PCA, explaining 74.91% of total variable. Cu, Ni, Fe, Co, Sc, Al, Ca, and Mg were mainly associated with the weathering and erosion of various rocks and minerals, while an anthropogenic source was identified for Cd and As. Although erosion was one source of Pb and Zn, they were also input by atmospheric deposition and industrial pollutions. NO $_{3}^{-}$ and Se were mainly associated with agriculture activities. However, Hg and Cr showed different sources. CA confirmed and completed the results obtained by PCA, classifying the data into two large groups representing different areas. Group 1 referred to the upper reaches which represented samples mainly corresponding to natural background areas. Group 2 referred to the middle and lower reaches including samples under anthropogenic influence. Meanwhile, group 2 was subdivided into three new groups, representing agricultural, industrial, and various artificial pollution sources, respectively.