青海瓦里关大气中多环芳烃的研究

2005年4月2日～5月23日,对瓦里关大气中的气相和颗粒相多环芳烃(PAHs)进行了连续观测.结果表明,总PAHs浓度为7.43～29.96ng/m³,气相PAHs的浓度为7.01～26.10ng/m³,颗粒相PAHs的浓度为0.28～7.84ng/m³,气相中PAHs占总浓度的66.5%～98.8%.气粒分配系数(K_p)与过冷饱和蒸汽压(PL0)呈良好相关性(R₂=0.67～0.92),斜率(mr)均>-1.瓦里关大气中PAHs的浓度受温度、风速、大气逆温层、大气长距离迁移等因素的影响.     

非离子有机物淡水沉积物质量基准推导方法——以林丹为例

沉积物质量基准是对水质基准的补充,对水质管理有重要意义.国际上有多种建立沉积物质量基准的方法,其中,相平衡分配法是美国环境保护局推荐使用的方法之一.相平衡分配法利用污染物的沉积物-水平衡分配系数(Kp)和水质基准中污染物的最终慢性毒性值(FCV)计算污染物的沉积物质量基准值(SQC).当缺乏污染物的沉积物生物毒性效应数...     

Miseq测序分析活性污泥系统中细菌群落的动态变化

采用基于16S rRNA基因的Miseq测序方法,分析了某小试序批式反应器(SBR)中,细菌群落结构在1年中的动态变化。在研究中,系统运行稳定,COD出水浓度均在40 mg/L以下,总氮(TN)和总磷(TP)出水浓度分别在20 mg/L和0.3 mg/L之下。细菌的群落组成变化明显,在检测到的2094个OTU中,有176个OTU只存在于3个以下的样品中。在385个属的细菌中,有54个属的微生物只存在于3个以下的样品中。移动窗口分析表明,系统中细菌群落的平均变化率Δt(30 d)为21.3%±6.2%,稳定的系统功能并未耦合稳定的细菌群落结构。Mantel test分析表明,溶解氧(DO),进水COD浓度和温度对细菌群落结构有显著影响。方差分解分析(VPA)结果表明,水质参数及运行参数可分别解释23.6%和21.5%的群落结构变化。     

Interpreting beta‐diversity components over time to conserve metacommunities in highly dynamic ecosystems

The concept of metacommunity (i.e., a set of local communities linked by dispersal) has gained great popularity among community ecologists. However, metacommunity research mostly addresses questions on spatial patterns of biodiversity at the regional scale, whereas conservation planning requires quantifying temporal variation in those metacommunities and the contributions that individual (local) sites make to regional dynamics. We propose that recent advances in diversity‐partitioning methods may allow for a better understanding of metacommunity dynamics and the identification of keystone sites. We used time series of the 2 components of beta diversity (richness and replacement) and the contributions of local sites to these components to examine which sites controlled source‐sink dynamics in a highly dynamic model system (an intermittent river). The relative importance of the richness and replacement components of beta diversity fluctuated over time, and sample aggregation led to underestimation of beta diversity by up to 35%. Our literature review revealed that research on intermittent rivers would benefit greatly from examination of beta‐diversity components over time. Adequately appraising spatiotemporal variability in community composition and identifying sites that are pivotal for maintaining biodiversity at the landscape scale are key needs for conservation prioritization and planning. Thus, our framework may be used to guide conservation actions in highly dynamic ecosystems when time‐series data describing biodiversity across sites connected by dispersal are available.     

关于成矿流体地球化学研究的几个问题

成矿流体地球化学是当前正蓬勃发展的流体地质学研究的一个重要分支。本文对八十年代以来国际上关于成矿流体地球化学研究的几个问题做了阐述，涉及到元素在熔体－溶液平衡体系中的分配、热水溶液系统中成矿元素的配合物形式及其主要影响因素，金属从成矿流体中沉淀机理研究等。提出了在成矿流体地球化学研究方面应重视的问题。     

Environmental control and spatial structure in ecological communities: an example using oribatid mites (Acari,Oribatei)

We have recently proposed to use partial canonical ordinations to partition the variation of species abundance data into four additive components: environmental at a local scale, the spatial component of the environmental influence, pure spatial, and an undetermined fraction. By means of an example, we show how to use the information contained in these fractions to provide better insight into the data. In particular, the interpretation is assisted by separately mapping the various canonical axes and relating them to possible generating processes. We derive a general framework for the causal interpretation of the various fractions of this partition, which includes the environmental and the biotic control models, as well as historical dynamics.Daniel Borcard is research associate in animal ecology at Universite de Neuchâtel, Switzerland. He is interested in soil ecology, and presently working on fundamental and applied projects dealing with peat bog ecology and protection, community succession dynamics, as well as effects of agriculture on mite and insect communities. In order to develop the statistical tools necessary for these projects, he also works in collaboration with Pierre Legendre on modeling the spatial structure of ecological communities. $Pierre Legendre is professor of quantitative biology at Universite de Montreal. He is a former Killam Research Fellow (1989–91), and a member of the Royal Society of Canada since 1992. He is the author of some 100 refereed articles, over 250 papers presented at scientific meetings and research seminars, dealing with numerical ecology, community ecology, environmental assessment and spatial analysis, and textbooks (in French and English) on numerical ecology. During the past 5 years, he served as the Secretary-Treasurer of the International Federation of Classification Societies. *We thank Dr V.M. Behan-Pelletier, of Agriculture Canada, for her help in the identification of the Oribatid mites, and Mrs Lucie Fortin and Dr P. Neumann, Universite de Montreal, for their identifications of the Sphagnum species. This research was carried out during tenure of a Postdoctoral Fellowship of the Swiss National Foundation for Scientific Research by D. Borcard, and of a Killam Research Fellowship of the Canada Council by P. Legendre. It was also supported by NSERC grant No. A7738 to P. Legendre. This is contribution No. 392 of the Groupe d'Écologie des Eaux douccs, Universite de Montreal. The authors wish to dedicate this paper with gratitude to Mr Alain Vaudor, computer analyst in Pierre Legendre's laboratory, who has largely contributed to the planning of this research. Mr Vaudor passed away on October 31, 1991, at age 46. The package for multivariate and spatial data analysis that he has produced during his computer scientist career is available to researchers from P. Legendre.     

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     

Reverse quantitative structure-activity relationship for modelling the sorption of esfenvalerate to dissolved organic matter. A multivariate approach

The sorption of the pyrethroid, esfenvalerate, to the dissolved and/or dispersed fraction of eight different natural humic compounds has been investigated. The dissolved organic matters (DOMs) included in this study originate from ground water, soil pore water, and surface waters. Sorption was modelled at DOM concentration levels where equilibrium partitioning of esfenvalerate between DOM and the aqueous bulk phase prevails. The inherent characteristics of the eight different humic materials, quantified in the preceding paper by Thomsen et al. (2002, this issue (PII: S0045-6535(02)00335-1)), have been used as explanatory variables for modelling this equilibrium partitioning. Using a reverse QSAR approach based on by projection-into-latent-structure regression (PLS-R) inherent sorbent properties determining for the sorption affinity of esfenvalerate to DOM were analysed. For all humic substances a decrease in the DOM-normalised equilibrium-partitioning coefficient, K_DOM, with increasing concentration of DOM was observed. Significant variations in K_DOM values, as function of the inherent characteristics of the individual humic substances, were found at DOM concentrations of 75 and 100 ppm, respectively. The latter is a strong indication of variations in sorption mechanisms of esfenvalerate to DOM of varying inherent properties. Groupings in the principal property space quantifying DOMs may indicate that separate models are needed for quantifying the equilibrium partitioning to different classes of DOM.     

A tool for estimating the contribution of water-soluble organic compounds to the particle mass and condensational growth in the atmosphere

In this theoretical investigation, we elucidated several factors governing the ability of organic, water-soluble vapours to participate into either the secondary organic aerosol formation or particle condensational growth in the atmosphere. The corresponding requirements for physico-chemical properties of the vapour were estimated. These estimates were also compared with the properties of several difunctional carboxylic acids identified in the atmosphere. Our analysis indicates that while many of the considered compounds are expected to contribute to the total particle mass in the atmosphere, their role in particle condensational growth process remains uncertain. This uncertainty emerges from the fact that the saturation ratio of an organic vapour does not alone determine its ability to act as a “nonvolatile” compound. Instead, the hygroscopic and chemical properties of the vapour, as well as the particle pH and size, have also to be taken into account.     

Unique products from the reaction of naphthalene with the hydroxyl radical

Many of the products of the reaction of naphthalene (Naph) with the OH radical in a reaction chamber were identified. Previously unidentified products included 1,2-naphthoquinone (NQ), oxygenated indenes and benzopyrones. Possible pathways for the formation of 1,2-NQ and 1,4-NQ are proposed. In the chamber reactions, more 1,2-NQ than 1,4-NQ partitioned to the particle phase. From this result we infer that, in the atmosphere, the percentage of 1,2-NQ in the particle phase should be greater than that for the 1,4-NQ. Because both of these compounds are considered to be toxic, and since they appear in both the gas and particle phases in the reaction chamber, and by implication in the atmosphere, it is considered important that both the gas and particle phases of these two compounds should be measured to assess their impact on human health.