The phenology of phytoplankton blooms: Ecosystem indicators from remote sensing

Remote sensing offers many advantages in the development of ecosystem indicators for the pelagic zone of the ocean. Particularly suitable in this context are the indicators arising from time series that can be constructed from remotely sensed data. For example, using ocean-colour radiometry, the phenology of phytoplankton blooms can be assessed. Metrics defined in this way show promise as informative indicators for the entire pelagic ecosystem. A simple phytoplankton–substrate model, with forcing dependent on latitude and day number is used to explore the qualitative features of bloom phenology for comparison with the results observed in a suite of 10-year time series of chlorophyll concentration, as assessed by remote sensing, from the Northwest Atlantic Ocean. The model reveals features of the dynamics that might otherwise have been overlooked in evaluation of the observational data.     

An empirical analysis of economic strategies for controlling air pollution

In evaluating current environmental protection policy, economists often note that current regulations are more costly than necessary to meet environmental quality standards. While the a priori case is strong that current regulatory approaches are resulting in higher-than-necessary costs to attain environmental standards, there is relatively little empirical evidence to support this claim. The purpose of this paper is to supply some of the missing evidence by presenting the results of one study that assesses some of the potential savings associated with implementing economic, rather than command-and-control, regulatory approaches to abate one type of air pollution in one region of the country. Specifically, the paper examines the costs of meeting a prospective short-term standard for nitrogen dioxide under a range of alternative emissions control strategies for stationary sources of nitrogen oxide emissions in the Chicago Air Quality Control Region. The alternative strategies that are considered range from those that might result under current regulatory policy to those that economic policy approaches (such as emissions charges or marketable permits) are designed to implement. The analysis shows that the most efficient program of emissions controls may be more than an order of magnitude less costly than current regulatory strategies, and that economic approaches have additional advantages over more conventional regulatory approaches.     

磷酸三丁酯(TBP)对苯酚的络合萃取

基于可逆络合反应的萃取分离方法对极性有机物稀溶液具有高效性和高选择性.本文系统进行了磷酸三丁酯(TBP)对苯酚稀溶液的络合萃取的实验研.负载有机相的红外谱图分析表明,TBP与苯酚通过氢键缔合形成萃合物.以TBP-煤油为萃取剂对工业含酚废水进行了萃取平衡和错流萃取实验.讨论了其应用的可能性及开发新的有效的络合萃取剂的途径.     

Host acceptance behaviour of the small ermine moth Yponomeuta cagnagellus: larvae and adults use different stimuli

Summary. The sugar alcohol dulcitol is a strong feeding stimulant for larvae of the small ermine moth Yponomeuta cagnagellus. In this paper we tested the hypothesis that dulcitol also acts as an oviposition stimulant for this species. We found that the sugar-alcohol dulcitol was present on the surface of the host Euonymus europaeus. We also showed that (as yet unidentified compounds) can be systemically transferred (i.e. by uptake and transport via the vascular system) from E. europaeus, to the non-host Crataegus monogyna and stimulate oviposition. However, no evidence was found that this stimulatory activity was due to dulcitol. Systemic enrichment of C. monogyna with dulcitol did not induce oviposition on this plant. Neither was the application of pure dulcitol on artificial twigs effective. In addition it was shown that when dulcitol was removed from host plant extracts, oviposition stimulatory activity was retained in the fraction without dulcitol. Synergism between dulcitol and other stimulants could not be demonstrated, however, high concentrations of dulcitol in combination with the main stimulant(s) showed a trend towards enhanced oviposition. It is concluded that the sugar alcohol dulcitol can only play a limited role in adult host acceptance behaviour. The hypothesis that a host shift in the genus Yponomeuta from Celastraceae to Rosaceae might have been facilitated by the presence of small amounts of dulcitol in Rosaceae therefore needs to be restricted to larval feeding behaviour. Received 20 August 1999; accepted 6 December 1999     

NaOH溶液对有机相苯酚反萃取的研究

本文系统进行了ＮａＯＨ溶液对负载苯酚的ＴＢＰ＋煤油溶剂的反萃取平衡实验。考虑苯酚的支萃取平衡和解离平衡,建立了反萃取的计算模式,并证明了模型的可行性。本文还讨论了ＮａＯＨ溶液浓度,油水相比,萃取平衡分配系数,溶剂中的负载苯酚浓度和ＮａＯＨ溶液中初始酚含量对反萃取率的影响。     

The significance of metal hyperaccumulation for biotic interactions

Metal hyperaccumulating plants contain very high metal contents. Because of the general toxicity of metals, chemically-mediated biotic interactions involving hyperaccumulating plants may differ greatly from those of non-hyperaccumulators. Recent research has demonstrated a defensive function for hyperaccumulated metals against herbivores and pathogens. We predict that some herbivore/pathogen species have evolved metal tolerance, and suggest that resulting high metal levels in herbivores/pathogens may defend them against their own predators. Little is known regarding interference and commensal interactions involving hyperaccumulating plants. Decreased competition may occur through an interference interaction similar to allelopathy, in which enrichment of metal in the soil under a hyperaccumulator plant's canopy may inhibit another plant species, thus resulting in “elemental allelopathy”. Metal enrichment of soil under hyperaccumulators also may result in commensalism if another plant species (possibly another hyperaccumulator) derives a benefit from growing in the metal-enriched soil under the canopy of a hyperaccumulating overstory plant. It seems likely that high-metal plant litter will host a specialized microflora of decomposers and may affect nutrient cycling rates. Mutualist biotic interactions also may be affected by the elevated metal contents of hyperaccumulating species. Mycorrhizal fungi may form mutualisms with hyperaccumulators, but the phenomenon is poorly-explored. The few cases investigated to date have not detected mycorrhizae. Pollination and seed dispersal mechanisms may require biotic vectors that might be affected by plant metal content. Hyperaccumulating plants may have solved this dilemma in three ways. First, some may rely on abiotic vectors for pollen or seed dispersal. Second, biotic vectors used by these species may have varied diets and thus dilute metal intake to non-toxic levels. Finally, biotic vectors may have evolved tolerance of elevated dietary levels of metals, and perhaps have become specialists on hyperaccumulator species. Received 7 November 1997; accepted 28 December 1997.     

Phototransformation of fibrate drugs in aqueous media

The photochemical conversion of bezafibrate, gemfibrozil, fenofibrate and fenofibric acid has been examined in aqueous media. Irradiation with a solar simulator in distilled water caused about 10% degradation for the first three drugs after 200 hr, while fenofibric acid was completely degraded after 100 hr. Experiments have also been performed in the presence of nitrates or humic acids, considered as environmental photosensitizers, and only for gemfibrozil a reduction of degradation has been observed. Photoproducts have been characterized and the mechanistic pathways discussed on the basis of experimental and literature data.     

环境样品前处理技术及其进展（二）

在前文中讨论了环境样品的制备、前处理的概况，以及超临界流体萃取法。本文将继续报导近年来环境样品制备与前处理领域中其他一些新技术和新方法，包括固相萃取（ＳＰＥ）、微波溶出（ＭＷＤ）和液膜萃取（ＳＬＭ）法，阐述了这些方法的基本原理、操作过程、各种实验参数的影响，及其在环境样品制备与前处理中的应用，并探讨了该领域的发展动向。     

利用氧化铝-改性硅胶联柱分离测定水中多氯联苯

本文介绍一种多氯联苯(PCBs)与农药的分离和气相色谱分析PCBs新方法.富集浓缩后的样品首先经浓硫酸酸洗.排除大多数干扰PCBs测定的有机化合物,然后利用氧化铝-硅胶(Ag~+)联柱实现了PCBs和干扰其测定的农药的完全分离,应用毛细管气相色谱分析测试了水样中多氯联苯多种同系物、同分异构体的含量.其方法的回收率在79—88%之间.     

生物体内环形挥发性甲基硅氧烷的分布、行为及效应研究进展

近年来,环形挥发性甲基硅氧烷(cVMSs)因其优异的物化特性而被广泛应用在工业生产和日常生活的各个方面,特别是经常被添加到个人护理品(PCPs)等各类消费品中.目前,人们对cVMSs在环境介质中的污染水平及其迁移转化行为有了一定的了解.另外,cVMSs兼有疏水性和挥发性,且难以进行生物降解,因此该类物质进入环境后潜在的...     

高炉洗气含氰废水除氰方法研究—气化分离与富集

本文用ＣＯ２气体气体化分离含氰废水中的氰，用乙醛等醛类吸收富集挥发出来的氰化氢而使氰以回收利用。气化分离除氰后，水中残余氰的浓度小于０．５ｐｐｍ。对醛类与ＨＣＮ反应的动力学和热力学性质的研究和吸收试验表明，乙醛等低分子醛能快速和完全地吸收气化分离出的ＨＣＮ，并得到α－羟基腈、羟基酸及其盐等系列产品。     

EDTA reduces lead accumulation in Symphytum officinale L. (comfrey) roots

The addition of EDTA in phytoextraction studies has been reported to increase heavy metal accumulation in above-ground parts or to have no negative impact on the overall (root/shoot) accumulation levels in terrestrial plants. At a purely quantitative level, this study assessed the phytoextraction potential of a previously untested high-biomass terrestrial plant, Symphytum officinale L. (comfrey), in the presence of Pb and EDTA. In this hydroponic-based study, we report a small increase in shoot accumulation of Pb with EDTA but, conversely, the presence of EDTA in the nutrient medium markedly reduced the overall quantity of Pb in the plant root by at least 80%. The loss does not appear to be explained by EDTA acting alone, increased transport of Pb to the shoots, or anionic charge repulsion of the [PbEDTA]^2? complex. The elusive action and negative effect of EDTA on Pb accumulation in S. officinale provides additional reasons towards a growing trend away from the use of EDTA as a chelating agent in phytoextraction.     

高温固硫反应中锶化合物的促进作用

本文论述了锶化合物在高温燃烧条件下固硫反应的促进作用，通过Ｘ－射线粉晶衍射及扫描电镜的研究，证明形成含硫酸钙的复合盐的生成是提高固硫率的关键，用该方法制成的工业型煤，在实际锅炉中试烧其固硫率可达７０％，是烟气排烟脱硫的有效方法之一，对净化大气，减少污染有现实意义。     

乐安江沉积物酸碱特性及其对重金属释放特性的影响

本文对乐安江沉积物样品的金属总量、酸碱特性进行了测定和不同pH条件下金属的释放实验.结果表明,乐安江沉积物中Cu,Pb,Zn,Cd和As的浓度均高于一般水体沉积物的本底值.从重金属的移动性分析,存在沉积物重金属对水体产生二次污染的可能.沉积物所含重金属随pH变化产生的金属释放顺序是Zn>Cu>Cd.Pb.     

拟除虫菊酯在不同猝灭体系中的光化学降解

本文选择了具有抗氧作用或光屏蔽作用的六种物质，测定了它们在不同浓度配比，不同光照时间，不同充气条件下对这四种拟除虫菊光解稳定性的影响，结果表明，它们对拟除虫菊酯有不同程度的光稳定作用，光屏蔽型稳定对浓度的变化更为敏感，耗氧型稳定剂由于自身的消耗对光照时间，充氧条件为敏感，由此可见，不同的环境条件对拟除虫菊酯类农药的残留产生较大影响，同时，使用光稳剂将是一种增强拟除虫菊酯光稳定性，充分发挥杀虫作用的     

抗生素抗性基因在环境中的来源、传播扩散及生态风险

近年来,由于抗生素的滥用首先诱导动物体内产生抗生素抗性基因(antib iotic resistance genes,ARGs),从而加速了抗性基因在环境中细菌间的传播扩散.目前,抗生素抗性基因作为一类新型环境污染物,在不同环境介质中的传播、扩散可能比抗生素本身的环境危害更大.本文针对抗生素抗性基因在地表水、地下水、医疗废水、城市污水处理厂、养殖场、土壤、沉积物以及大气环境中的来源、分布、传播情况以及国内外最新研究动态进行综述.分析了抗生素抗性基因在环境中的潜在传播途径及其可能影响因素,并指出光照,厌氧,高温处理可以有效遏制抗生素抗性基因在环境中的传播和扩散.揭示了抗生素抗性基因可能造成的生态风险,针对我国对该类污染物的研究现状,提出了今后的研究重点.     

环境质量的模糊综合评判—灰色关联分析

本文简要分析了环境质量评价中目前广泛应用的各种评价方法与模型。在此基础上提出环境质量综合评判－灰色关联优势分析复合模型，应用于黄山风景区景观生态环境质量的综合评价，取得了满意的结果。     

Human drivers,biophysical changes,and climatic variation affecting contemporary cropping proportions in the northern prairie of the U.S

Grassland to cropland conversion in the northern prairie of the United States has been a topic of recent land use change studies. Within this region more corn and soybeans are grown now (2017) than in the past, but most studies to date have not examined multi-decadal trends and the synergistic web of socio-ecological driving forces involved, opting instead for short-term analyses and easily targeted agents of change. This paper examines the coalescing of biophysical and socioeconomic driving forces that have brought change to the agricultural landscape of this region between 1980 and 2013. While land conversion has occurred, most of the region’s cropland in 2013 had been previously cropped by the early 1980s. Furthermore, the agricultural conditions in which crops were grown during those three decades have changed considerably because of non-biophysical alterations to production practices and changing agricultural markets. Findings revealed that human drivers played more of a role in crop change than biophysical changes, that blending quantitative and qualitative methods to tell a more complete story of crop change in this region was difficult because of the synergistic characteristics of the drivers involved, and that more research is needed to understand how farmers make crop choice decisions.     

主成份分析在城市生态经济动态评价中的应用

城市生态经济的动态发展过程,可以看作多种生态关系要素相互作用的集合沿时序轴波动的轨迹.在这种多变量分析中,完全采用人工筛选变量的方法难以避免确定权重等过程所带来的主观干扰.PCA(主成份分析)采用一种特殊的转换降维方法,根据原始数据自身的特点综合成几个主导因子,并最大程度反应原始数据的信息量.本文根据天津市四十年18项生态经济指标,采用相关矩阵和PCA双重筛选过程,得到载荷量大于90%的前三个主分量,将其作为天津市生态经济动态评价的基础.结果表明:天津市解放后四十年每十年一次的经济周期上迭加了自然社会等非经济因素的影响,表现出城市生态经济动态发展的三大阶段,这种发展主要受到宏观经济管理模式及其相应的投资机制的制约.     

土壤污染物的释放速率及阻隔措施的研究

本文测定了硝基苯,苯胺,萘和苯酚从土壤向大气释放的速度,这些污染物一开始都有较高的释放速率,几天后污染物的释放速率下降。清洁的粘土和水泥板覆盖在污染的土地上能有效地防止污染物向大气释放,可用于土壤的修复。