Isolation and characterization of Sporobolomyces sp. LF1 capable of degrading chlorimuron-ethyl

A yeast strain which was capable of degrading sulfonylurea herbicide chlorimuron-ethyl named as LF1 was isolated from a chlorimuron-ethyl contaminated soil near the warehouse of the factory producing chlorimuron-ethyl in Shenyang City, Northeast China. The strain was identified as Sporobolomyces sp., based on its morphological and physiological characteristics and the phylogenetic analysis of 18S rRNA gene sequence. So far, this is the only yeast strain of Sporobolomyces sp. which is able to degrade chlorimuronethyl. Incubation tests showed that when the initial concentration of chlorimuron-ethyl in culture was 5 mg/L, LF1 could degrade more than 77% of the herbicide after incubation for 4 d at 30°C. The possible mechanism of chlorimuron-ethyl degradation by LF1 could be the acidic hydrolysis caused by the acids from the metabolism of the yeast strain. Further study should be conducted to examine the pathways of chlorimuron-ethyl degradation by LF1 and to approach the feasibility of using LF1 to degrade the chlorimuron-ethyl in soil system.     

茂兰保护区小生境土壤微生物活性研究

以茂兰国家级自然保护区内三种植被（原生林、次生林、灌木林）下的土壤为研究对象,探讨了小生境土壤微生物数量、微生物量碳（BC）、微生物量氮（BN）、微生物熵（qSMBC）、基础呼吸及代谢熵（qCO2）的变化特征。结果表明：微生物数量、BC、BN、基础呼吸、qSMBC基本呈现石沟〉土面的趋势,qCO2则表现为土面〉石沟,即...     

Tetrasphaera聚磷菌研究进展及其除磷能力辨析

强化生物除磷（EBPR）工艺在污水脱氮除磷中扮演着重要角色，其机理研究与工程应用也较为成熟.长期以来，Accumulibacter菌属（A菌）作为EBPR工艺最主要的聚磷菌（PAOs）已被广泛接受.同时，具有聚磷能力的Tetrasphaera菌属（T菌）亦被发现，且在某些特定环境下其丰度甚至远高于A菌，进而引发业内一定的关注.本文通过对T菌发现、研究过程的梳理，总结了关于T菌丰度、代谢途径及影响其活性的因素等方面的研究成果.与A菌不同，T菌代谢途径具有多样性，可依赖发酵代谢进行细胞维持和增殖，其发酵产物甚至可以供给A菌利用.T菌可利用大分子有机物（如葡萄糖、氨基酸等）和VFAs（亲和性较低）进行厌氧释磷，继而完成好氧、甚至缺氧吸磷过程.T菌主要菌株（T.elongata）因缺少合成PHA相关酶基因而不能以PHA作为内聚产物在厌氧环境下储能；糖原和游离氨基酸被检测到可作为T菌的能源/碳源内聚物，但亦有结果相左的研究.借助于拉曼光谱技术，一些污水处理厂中T菌与A菌被证实对磷去除的贡献大小相当.总之，目前对T菌的研究还十分有限，现有研究仍不足以证明它们在EBPR中可稳定发挥除磷贡献.今后应在T菌不同代谢途径控制因素及所需环境条件方面进行深入研究，以确认T菌可否持续、稳定地实现除磷作用.     

稻草还田对土壤微生物群落功能多样性的影响

为了探讨稻草还田的微生物学过程与效应,借助平板涂抹法和BIOLOG检测法,比较研究了免耕条件下3种不同稻草还田量(33%、67%和100%,以稻草不还田土壤为对照)对晚稻田土壤微生物群落功能多样性的影响.结果表明:①土壤细菌数量差异显著,以67%稻草还田处理为最高,稻草不还田处理最低,稻草还田提高了土壤细菌数量;②碳源平均颜色变化率(AWCD法)在培养早期各处理间的差异不大,但随着培养时间的延长,67%和100%稻草还田处理土壤微生物的AWCD值显著大于对照和33%稻草还田处理组;③土壤微生物代谢多样性指数(丰富度和多样性)在3种稻草还田量处理土壤中也表现出明显差异,67%和100%稻草还田处理的土壤中微生物功能多样性显著大于33%稻草还田处理和对照;④67%和100%稻草还田处理显著改善了土壤微生物的功能多样性.以67%稻草还田处理改善土壤微生物群落结构和功能的效果最为显著.     

曝气生物滤池中碳和氮代谢特性

用充填陶瓷滤料的曝气生物滤池研究碳和氮代谢特性.曝气生物滤池进水氨氮为52 mg/L左右、COD为100 mg/L左右和回流比为200%时,经过20多d的运行,出水氨氮小于0.05 mg/L、COD小于25 mg/L、亚硝态氮为4.7 mg/L和硝态氮为7.1 mg/L,COD去除率达75%,氨氮去除率达99.9%,总氮去除率达78%;过大和过小的回流比对曝气生物滤池的运行性能都是不利的.研究成果可以应用于一般城市污水以及含低COD、高氨氮工业废水的处理.     

National contributions to global ecosystem values

Current conservation templates prioritize biogeographic regions with high intensity ecosystem values, such as exceptional species richness or threat. Intensity-based targets are an important consideration in global efforts, but they do not capture all available opportunities to conserve ecosystem values, including those that accrue in low intensity over large areas. We assess six globally-significant ecosystem values—intact wilderness, freshwater availability, productive marine environments, breeding habitat for migratory wildlife, soil carbon storage, and latitudinal potential for range shift in the face of climate change—to highlight opportunities for high-impact broadly-distributed contributions to global conservation. Nations can serve as a cohesive block of policy that can profoundly influence conservation outcomes. Contributions to global ecosystem values that exceed what is predicted by a nation's area alone, can give rise to countries with the capacity to act as ‘conservation superpowers’, such as Canada and Russia. For these conservation superpowers, a relatively small number of national policies can have environmental repercussions for the rest of the world.     

中国汽车行业钢铁物质流代谢研究

汽车行业在我国发展迅速,汽车行业的钢铁物质流代谢在整个国民经济的钢铁物质流代谢系统中的影响已不可忽视。研究中国汽车行业钢铁物质流代谢对再生资源利用产业、再制造行业的发展具有重要的意义。结合系统动力学方法及相关经验模型对中国汽车行业钢铁物质流代谢进行研究。首先通过Gompertz模型研究了世界主要国家汽车千人保有量与时间的关系,以此为参照设定中国汽车千人保有量随时间变化的相关参数。其次利用中国汽车行业钢铁物质流循环代谢的系统动力学模型,对系统关键流量、存量的动态变化过程进行考察分析,通过设定不同情景、不同寿命分布,研究中国汽车报废量、钢板和零件耗钢量随时间变化的规律,并探讨了零件再制造、汽车轻型化等问题。选取汽车千人保有量为260辆/千人的中等情景进行分析,考察时间为2011-2050年,结果表明报废汽车年折钢量与汽车行业钢材年消耗量比值不断上升,最终可达到1.2;再制造行业潜力巨大,零件再制造数量将近8亿件;延长汽车4 a寿命,可减少近一半的汽车报废量;通过轻型化,钢材年消耗量可减少18%,减少近650万t,累计减少1亿多吨钢材,节省大量资源,经济和环境效益显著。     

DBP高效降解菌群的富集及其降解特性研究

以邻苯二甲酸二丁酯(DBP)为唯一碳源及能源,从开封市垃圾焚烧发电厂活性污泥中富集得到细菌菌群LV-1,高通量测序显示LV-1共包含33个科、48个属,其中优势菌属为布鲁氏杆菌(Brucella sp.,62.78%)和中华杆菌(Sinobacter sp.,14.83%).在最佳降解条件下(30℃、p H6.0),LV-1 48 h内可将500 mg·L-1DBP降解93%左右,72 h内将1000 mg·L-1DBP降解95%以上.当DBP浓度为100~500 mg·L~(-1)时,LV-1对DBP的降解过程符合一级动力学方程,半衰期为13.64~19.20 h.利用GC-MS对DBP生物降解的中间产物进行分析,推测LV-1降解DBP的生化途径:DBP—→邻苯二甲酸-1-乙基-6-丁基酯(BEP)—→邻苯二甲酸单丁酯(MBP)—→邻苯二甲酸单乙酯(MEP)—→邻苯二甲酸(PA—→—→)CO_2+H_2O.此外,LV-1还能够有效降解侧链较短的邻苯二甲酸二甲酯(DMP)、邻苯二甲酸二乙酯(DEP)及PA.     

Shifts in a Pacific Ocean Fish Assemblage: the Potential Influence of Exploitation

Abstract:  As in many regions of the world, marine fishes and invertebrates along the Pacific coast of the United States have long been subjected to overexploitation. Despite this history, however, we lack basic information on the current status of many fishes along this coastline. We used data from a quarter century of fishery-independent, coast-wide trawl surveys to study systematically the demersal fish assemblages along the U.S. Pacific coast. We documented fundamental shifts in this fish assemblage. Average fish size, across a diversity of species, has declined 45% in 21 years. There have been major shifts in the constituent species of the assemblage, with some species achieving annual population growth rates of >10% and others declining in excess of 10% per year. Annual rate of change in population size appeared to be a function of life history interacting with fishing pressure. Negative trends in population size were particularly apparent in rockfish ( Sebastes spp.). However, across all taxa examined, trends in population size were associated with size of maturity, maximum size, and growth rate. Trends in population size were associated inversely with harvest levels, but stocks that mature late tended to decline faster than would be predicted by catch rates alone. Our results are disquieting because they raise the possibility that fishing-induced phase shifts in fish communities may affect the recovery of fishes, even after the implementation of severe fishing restrictions.     

Effects of male removal on female foraging behavior in the Eurasian treecreeper

In old, spruce-dominated forests of central Finland, Eurasian treecreepers Certhia familiaris divide their territories spatially during the breeding season. Females forage primarily on the upper parts of the tree trunks, while males use the lower parts of the tree trunks. In this study we removed males from eight territories in the early nestling period to see if the mate's absence would change the foraging patterns of the resident female. Widowed females foraged at lower heights, thus behaving more like paired males. These females also spent less time on each tree and on each foraging bout than did paired females. We conclude that male removal facilitated the change in a female's foraging niche and foraging time at the trees. Females may re-optimize their foraging site selection owing to the absence of dominant males and a consequent need to increase their parental care. Behavioral plasticity may be the mechanism of niche partitioning between the sexes in this species. Received: 28 June 1996 / Accepted after revision: 27 March 1997