Functional and community-level soil microbial responses to zinc addition may depend on test system biocomplexity

The effect of zinc on soil nitrification and composition of the microbial community in soil was investigated using a full factorial experiment with five zinc concentrations and four levels of biological complexity (microbes only, microbes and earthworms (Eisenia fetida), microbes and Italian ryegrass (Lolium multiflorum var. Macho), and microbes, ryegrass and earthworms). After 6 weeks of exposure, the activity of soil nitrifying bacteria was measured and the microbial community structure was characterized by phospholipid fatty acid (PLFA) analysis. Soil nitrification and several PLFA markers were significantly influenced by either zinc addition and/or the presence of earthworms or ryegrass, and one of the most pronounced changes was the increase of fungi and decrease of bacteria with increasing concentrations of zinc. Of particular interest, however, was the potential interaction between the presence of plants and/or earthworms and the effect of zinc, which the factorial study design allowed us to explore. Such an effect was observed in two cases: Earthworms reduced the positive effect of zinc on the fungal biomass (ANOVA, p=0.03), and the effect of earthworms on the soil nitrification activity depended on zinc concentration (ANOVA, p<0.05). The effect of earthworm presence was not very large, but it does show that multispecies tests might give information about metal toxicity or bioavailability that cannot be predicted from single-species tests.     

Modelling changes in forest soil chemistry at 16 Swedish coniferous forest sites following deposition reduction

The dynamic forest ecosystem model ForSAFE was applied at 16 coniferous forest sites in Sweden to investigate past and future changes in soil chemistry following changes in atmospheric deposition. The simulation shows a considerable historical soil acidification. Acidification in the southwest, where deposition has been greatest, was more expressed in the deepest soil layers, while it was more evenly distributed through the soil profile in central Sweden, and was greater in the upper soil layers in the north. The simulation also shows that a slight recovery took place after the reduction in emissions, but was counteracted by the effect of harvesting. The simulation predicts an increase in the number of acidified sites in the future. The results also suggest that future acidification will be mainly due to the enhanced tree growth resulting from the chronic high deposition of nitrogen and the removal of soil base cations through harvesting.     

植物及存水区对南方生物滞留池去污效果的影响

以柳叶马鞭草、菖蒲、鸢尾和美人蕉及南方红壤构建5个生物滞留池模拟装置,研究植物和IWS(内部存水区)及其交互作用对径流中TSS、COD、NH_3-N、NO_3~--N、TN和TP去除的影响,定期测定植物的叶绿素含量、株高和游离脯氨酸含量等生理指标,以探讨植物的生长适宜性。结果表明:植物对COD、NO_3~--N和TN的去除影响较大,其去除率分别为68.84%~77.28%、13.09%~59.61%和42.41%~71.75%,柳叶马鞭草和美人蕉的NO_3~--N及TN去除能力显著高于菖蒲和鸢尾(P柳叶马鞭草>鸢尾>菖蒲,美人蕉和柳叶马鞭草的去污效果和长势较好,适宜在南方生物滞留池中种植。     

零价铁还原地下水中对氯硝基苯的研究

采用间歇试验考察零价铁去除对氯硝基苯的效果,研究初始pH值、零价铁粒径、零价铁投加量和氧对反应过程的影响.结果表明,在中性和弱酸性条件下零价铁能有效去除对氯硝基苯,反应过程符合准一级动力学,反应终产物为对氯苯胺;降低零价铁粒径和增加零价铁投加量可提高对氯硝基苯的去除率.当零价铁粒径为0.05mm、投加量为0.5 g/L、对氯硝基苯初始质量浓度为25 mg/L,反应6h后,对氯硝基苯去除率可达100％.氧对零价铁还原对氯硝基苯具有竞争性抑制作用,但零价铁能消耗水中溶解氧并维持对氯硝基苯还原反应进行,与厌氧反应过程相比,空气-水体系对氯硝基苯去除率下降19.18％.研究表明,采用零价铁还原法可有效去除地下水中的对氯硝基苯.     

可燃气体爆炸破坏效应的试验研究

借助高速摄像机及ProAnalyst软件,研究可燃气体体积分数和障碍物对可燃气体爆炸破坏力的影响。测定不同体积分数下的甲烷-空气预混气体爆炸冲击波超压,和爆炸火焰波在有无乒乓球方向传播的平均速度。试验结果表明:超压和平均速度均随着甲烷体积分数的增加呈现先增大后减小的变化趋势,其最大值均出现在甲烷体积分数为10%～11%之间;同一体积分数下的甲烷-空气预混气体爆炸火焰波在有乒乓球方向传播的平均速度比没有乒乓球方向传播的平均速度大。根据试验结果,推导出可燃气体爆炸冲击波超压和爆炸火焰波传播平均速度与可燃气体体积分数之间的函数关系,并得出障碍物对爆炸火焰波传播的加速作用随着体积分数的增加呈现先加强后减弱的变化趋势。     

滴水湖水系表层沉积物中多氯联苯残留与风险评价

于2012年,每2个月采集一次上海人工滩涂湖泊——滴水湖水系表层沉积物,对其多氯联苯(PCBs)的残留水平进行了检测和分析.结果表明,研究期间闸外引水河和闸内引水河沉积物中7种PCBs的总量各月间变化较大,且总体呈上升趋势,而滴水湖沉积物中其总量四季变化幅度不大;空间分布上,闸外引水河[(844.74±687.62)ng/g]>闸内引水河[(516.83±645.45)ng/g]>>滴水湖[(81.63±72.18)ng/g].研究区PCBs组成以六氯联苯和七氯联苯为主,其次为五氯联苯和三氯联苯.采用主成分分析法对PCBs进行源解析,结果显示:PCBs污染源中进口电容器中PCBs的迁移占43%,油漆添加剂污染占33%;国产电容器和变压器污染占11%.生态风险评估表明,闸外引水河和闸内引水河沉积物PCBs对生物体的暴露有严重威胁;滴水湖沉积物PCBs对生物体的暴露有一定的潜在威胁.与国内外研究相比,闸外引水河和闸内引水河属于严重污染水平,滴水湖属于中等污染水平,相关部门应加强污染监管.     

The political significance of local agenda 21: The early stages of some European experience

Sustainable development, as it emerged in Agenda 21 from the Rio conference in 1992, will only be meaningful when it touches the lives of ordinary people; then it becomes a reality. Local Agenda 21 (LA21) seeks to achieve that objective. This article assesses the origins of LA21, reviews its social and political significance, and considers its prospects in the light of case study experience emerging from the UK, Germany and Norway, focusing on the role of local government as a major stakeholder in Agenda 21 (A21). The range of response to LA21 has proved to be varied. A successful transformation to a more sustainable world will require visionary political leadership, supportive administrations, networks of experience sharing, alliances with non-governmental organisations and local industry, and effective community mobilisation. All of that, in turn, requires equally supportive economic and social policy backing from national governments. This article will indicate that, not surprisingly, it is the domestic political context, nationally and locally, which in the main determines the speed and nature of response to LA21, now and in the future. By understanding and being aware of these contexts, factors impeding progress towards LA21 may be addressed, whilst at the same time retaining the diversity of response which is an essential part of local sustainability.     

16S rRNA基因技术在环境科学领域中的应用

随着分子生物学的发展，16S rRNA基因技术被逐渐应用到环境科学领域中。目前在环境保护和治理中，该技术主要被用于鉴定污染物的生物降解菌和分析环境样品中的微生物群落多样性，由于它不必将微生物培养分离出来，也就避免了在培养过程中可能出现的微生物去失的情况。本文对16S rRNA基因技术及其在环境科学领域中的应用现状和发展作了一简要介绍，并对16S rRNA基因技术存在的不足进行了讨论。     

非光合CO2同化微生物菌群的选育/优化及其群落结构分析

通过从海水及其沉积物中分离、筛选,并结合电子供体和无机碳源结构的优化以期获得不用光照与供氢的高效固碳微生物菌群;通过16S rDNA序列分析、比对等手段研究非光合固碳微生物菌群的结构,以期为优化群落配置,进一步提升固碳效率提供理论依据.结果显示,通过分离和长期驯化可从海洋中得到在普通好氧、厌氧条件下具有固碳能力的非光合微生物菌群.添加硫代硫酸钠、硫化钠和氢气作为电子供体可有效提升菌群的固碳效率,在以硫代硫酸钠为电子供体的好氧、厌氧条件下,该菌群的CO2同化效率分别可达10.44 mg/L和12.56 mg/L.该固碳菌群对混合无机碳源的同化效率显著高于单一碳源,在以CO2、碳酸氢钠及碳酸钠为混合碳源情况下,菌群好氧、厌氧固碳效率(以CO2计)分别可达110 mg.(L.d)-1,和72mg.(L.d)-1,接近氢氧化细菌的水平.微生物群落结构分析结果表明,添加不同电子供体后,固碳微生物菌群的优势种发生了显著变化,在发现的16个优势菌种中,11个是不可培养微生物,即其只能以共生方式存在.菌群混合培养时的固碳效率可能是多种菌共同作用的结果,因此优化固碳微生物菌群的结构和配比将有利于其固碳效率的进一步提升.     

太湖水体漫衰减系数特征及其对水生态环境影响分析

利用2006年10～11月太湖全湖不同区域光学属性的测量数据,就太湖水体漫衰减系数(K_d)特征、各影响因子对K_d的贡献率以及K_d对太湖水生态系统的影响进行分析.结果表明,太湖水体的漫衰减系数K_d以571 nm为分界点,在整个可见光波长范围内(400～700 nm)主要呈现2种变化趋势.第1种,在<571 nm波长范围内,K_d随着波长的增加呈现指数形式衰减,第2种,在>571 nm波长范围内,K_d表现为波动形式;在400～700 nm波长范围内,色素颗粒物的吸收系数是漫衰减系数第一贡献者,非色素颗粒物吸收系数和散射系数处于第二贡献者地位,而黄质吸收系数的贡献率相对最小;太湖水体漫衰减系数决定了太湖水生态系统中的光生态因子,K_d形成的“水体窗口”影响了太湖水域不同类型生态系统的形成,并为太湖“水华”的优势藻类铜绿微囊藻的出现提供了水下光场依据.