Experience in quantitative analysis of floristic structure and diversity in Samarskaya Luka

Quantitative methods have been applied to the study of floristic structure and diversity in Samarskaya Luka. The results show that Samarskaya Luka is a floristically heterogeneous area in which six elementary floras can be distinguished. This area has been assessed as a floristically autonomous formation, and its floristic representativeness was estimated.     

高原高寒污水处理系统的微生物群落特征

为研究高原高寒污水处理系统活性污泥的微生物群落结构及多样性,以拉萨、云南、四川的3座高原污水厂作为实验组,同时以重庆2座非高原污水厂作为对照,采用PCR-DGGE技术对比分析了高原与非高原污水厂的微生物特性.研究表明：高原污水厂样品与非高原样品在聚类中展现出了较为疏远的关系,微生物群落区别明显.受强紫外线辐照的抑制,高原高寒污水处理系统微生物多样性的平均水平显著低于非高原污水厂,较低的微生物多样性是导致高原高寒地区污染物去除效果不佳的一项重要原因.群落构成方面,共鉴定出16个优势菌属,对应Proteobacteria、Bacteroidetes、Firmicutes、Verrucomicrobia 4个门.组间差异分析结果发现,高原组中丰度显著偏高的菌属只有Prosthecobacter,该菌在污水厂内分布广泛,且能够适应高原低温的条件.对于大多数活性污泥微生物而言,高原强紫外线是不利的生存条件.因此,减少高原露天污水处理系统的紫外辐照,是提升污水处理效能的一个潜在措施.     

Microbiological characteristics in a zero-valent iron reactive barrier

Zero-valent iron (Fe⁰)-based permeable reactive barriertreatment has been generating great interest for passivegroundwater remediation, yet few studies have paid particularattention to the microbial activity and characteristics withinand in the vicinity of the Fe⁰-barrier matrix. The presentstudy was undertaken to evaluate the microbial population andcommunity composition in the reducing zone of influence byFe⁰ corrosion in the barrier at the Oak Ridge Y-12 Plantsite. Both phospholipid fatty acids and DNA analyses were usedto determine the total microbial population and microbialfunctional groups, including sulfate-reducing bacteria,denitrifying bacteria, and methanogens, in groundwater andsoil/iron core samples. A diverse microbial community wasidentified in the strongly reducing Fe⁰ environment despitea relatively high pH condition within the Fe⁰ barrier (up topH 10). In comparison with those found in the backgroundsoil/groundwater samples, the enhanced microbial populationranged from 1 to 3 orders of magnitude and appeared to increase from upgradient of the barrier to downgradient soil. Inaddition, microbial community composition appeared to change overtime, and the bacterial types of microorganismsincreased consistently as the barrier aged. DNA analysisindicated the presence of sulfate-reducing and denitrifyingbacteria in the barrier and its surrounding soil. However, theactivity of methanogens was found to be relatively low,presumably as a result of the competition by sulfate/metal-reducing bacteria and denitrifying bacteria because of the unlimited availability of sulfate and nitrate in the site groundwater. Results of this study provide evidenceof a diverse microbial population within and in the vicinity ofthe iron barrier, although the important roles of microbial activity, either beneficially or detrimentally, on the longevityand enduring efficiency of the Fe⁰ barriers are yet to be evaluated.     

evaluation of a measurement method for forest vegetation in a large-scale ecological survey

We evaluate a field method for determining species richness andcanopy cover of vascular plants for the Forest Health MonitoringProgram (FHM), an ecological survey of U.S. forests. Measurementsare taken within 12 1-m² quadrats on 1/15 ha plots in FHM.Species richness and cover are determined for four height classes(strata) within each quadrat and aggregated by stratum over the entireplot. We estimated (1) the agreement between experienced trainers andinexperienced technicians who collected the data on this survey(accuracy) and (2) the agreement among the technicians (precision) forresults on species richness and cover from 3 test plots at 3 timeintervals. The methods appear to be highly precise, although somediscrepancies with the values obtained by the trainers were found.Trainers found significantly more species in the ground stratum (0–0.6 m) and measured significantly more cover in the uppermost stratum(>4.9 m). The proportion of variation due to measurement error andtemporal variability was less than 13% for species richness (all strata)and cover (all but one stratum). This indicates that the method issuitable for monitoring changes in species richness and canopy coverfor a large-scale synoptic monitoring project such as FHM.     

The Impact of Landsat Satellite Monitoring on Conservation Biology

Landsat 7s recent malfunctioning will result in significant gaps in long-term satellite monitoring of Earth, affecting not only the research of the Earth science community but also conservation users of these data. To determine whether or how important Landsat monitoring is for conservation and natural resource management, we reviewed the Landsat programs history with special emphasis on the development of user groups. We also conducted a bibliographic search to determine the extent to which conservation research has been based on Landsat data. Conservation biologists were not an early user group of Landsat data because a) biologists lacked technical capacity – computers and software – to analyze these data; b) Landsats 1980s commercialization rendered images too costly for biologists budgets; and c) the broad-scale disciplines of conservation biology and landscape ecology did not develop until the mid-to-late 1980s. All these conditions had changed by the 1990s and Landsat imagery became an important tool for conservation biology. Satellite monitoring and Landsat continuity are mandated by the Land Remote Sensing Act of 1992. This legislation leaves open commercial options. However, past experiments with commercial operations were neither viable nor economical, and severely reduced the quality of monitoring, archiving and data access for academia and the public. Future satellite monitoring programs are essential for conservation and natural resource management, must provide continuity with Landsat, and should be government operated.     

论DNA分子标记在家畜遗传多样性保护中的应用

本文就ＤＮＡ分子遗传标记在家畜遗传多样性保护中应用的可行性及途径进行了探讨，提出了家畜遗传多样性标记辅助保护新策略。     

生物接触氧化法处理煤矿生活污水的工艺探讨

根据煤矿生活污水的特点，结合几年来工作和学习的经验及体会，论述生物接触氧化法的工艺流程，讨论设计中遇到的问题，探讨设计参数，使用填料和选取方法，为今后的污水处理站设计提供参考。     

生物除磷机理及试验研究

介绍了生物除磷机理、生物除磷系统的积磷细菌、生物除磷所需的环境条件。SBR法除磷的试验研究表明,应用SBR活性污泥系统进行除磷,需要一定的厌氧条件;且须在厌氧阶段进行充足的曝气。试验结果证明,SBR法在时间上控制的灵活性非常适合生物除磷的环境条件。厌氧与好氧相结合,能够提高磷的去除率或降低出水磷的浓度,磷的去除率可达90%左右。     

Degradation of Populus euphratica community in the lower reaches of the Tarim River, Xinjiang, China

IntroductionRiparian systems are aquatic-terrestrial ecotones withunique biotic , biophysical and landscape characteristics(Gregory, 1991 ; Naiman, 1997 ; Wiens , 2002) and areshaped by fluvial geomorphic processes . Riparian plantcommunities perform an i…