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1.
胞外聚合物(EPS)在藻菌生物膜去除污水中Cd的作用   总被引:18,自引:2,他引:16  
藻菌生物膜在自然水体和污水生物处理工艺中普遍存在,它们在去除水体中重金属起重要作用。笔者在室内模拟实验的基础上,探讨了丝藻(Ulothrixsp.)-细菌生物膜所分泌的胞外聚合物(EPS)与藻菌生物膜去除毒性金属Cd之间的关系。研究结果表明,EPS主要由丝藻产生,其含量与污水中Cd的去除效率及生物膜中Cd的积累量之间相关性良好。而且,丝藻所分泌的EPS为与其共生的细菌及其本身提供了一个缓冲Cd毒性的微环境,这使藻菌生物膜能在不利的环境中保持较高的活性并能持续有效地去除水体中的Cd。   相似文献   

2.
魏钰  雷光春 《自然资源学报》2019,34(9):1820-1832
自然保护事业已经进入人与自然和谐的综合保护阶段,突破传统生物群落保护的要素式思维,从生态特征、生态系统健康和自组织能力等视角系统实施生态系统完整性保护,已基本成为共识。中国经历了长期部门化割裂管理,在国家公园体制建设过程中开始由分散走向统一,要求将山水林田湖草作为生命共同体进行生态系统完整性保护。基于集合种群等空间生态学理论,提出国家公园生态系统完整性不仅意味着内部自然空间的完整,更需着眼国家生态安全的大局和自然保护地体系的战略布局。国家公园只有成为生态地理区的节点并辐射周边区域,有效平衡行政区域之间以及人与自然之间的关系,才能真正实现完整生态系统的长效保护。目前,国内既有研究在指导全域布局和平衡人地关系方面仍考虑不足,试点过程中还存在管理型技术方法欠缺、空间边界受限于行政边界、未能从全局着眼构建以国家公园为核心的生态系统完整性网络、未充分考虑差异化的人地关系等问题。未来需要着眼大局,有效平衡国家公园及其周边区域的关系、不同行政区域之间的关系、国家公园人与自然的关系,从而实现生态系统完整性的长效保护。  相似文献   

3.
生态完整性评价的理论和实践   总被引:2,自引:0,他引:2  
阐述了生态完整性的概念、内涵和评价方法。生态完整性即生态系统结构和功能的完整性,生态完整性评价可从评价区生态系统的生产力和稳定性两个角度进行。然后以原料林基地建设工程为例,进行了生态完整性评价。评价结果表明,工程实施后,评价区生产力明显增加,对雏护生态完整性有利。但大面积种植原料林,降低了生态系统的阻抗稳定性,对生态完整性不利。为此,在整地造林时,必须保护原料林周围的次生林;如果一块原料林面积超过50亩,建议横纵各建一条宽30米的乔灌混生的隔离带,增加植被的异质性,从而增强其阻抗稳定性。  相似文献   

4.
Viruses are the causative agents of an estimated 60% of human infections worldwide. The most common viral illnesses are produced by enteric and respiratory viruses. Transmission of these viruses from an infected person or animal to a new host can occur via several routes. Existing studies strongly suggest that contaminated fomites or surfaces play an important role in the spreading of viral diseases. The potential of viral spreading via contaminated surfaces depends particularly on the ability of the virus to maintain infectivity whilst it is in the environment. This is affected by a combination of biological, physical and chemical factors. This review summarises current knowledge about the influence of environmental factors on the survival and spread of viruses via contaminated surfaces.  相似文献   

5.
《Journal of Cleaner Production》2007,15(13-14):1359-1372
This paper mostly deals with the role of energy, matter and information flows within both environmental and human-dominated systems. Sustainable growth and development of both kinds of systems require optimum use of available resources for maximum power output, as suggested by Lotka's Maximum Power Principle [Lotka AJ. Contribution to the energetics of evolution. In: Proceedings of the national academy of sciences of the United States of America, vol. 8. 1922, p. 147–50; Lotka AJ. Natural selection as a physical principle. In: Proceedings of the national academy of sciences of the United States of America, vol. 8. 1922, p. 151–5.], recently restated by Odum [Odum HT. Maximum power and efficiency: a rebuttal. Ecol Model 1983;20:71–82; Odum HT. Environmental accounting. Emergy and environmental decision making. N.Y.: John Wiley & Sons; 1996.] as Maximum Em-Power Principle within the framework of his Emergy Synthesis approach. In times of declining resources, this principle translates into increased efficiency and optimum use of any kind of waste and co-products. Ecosystems and any self-organizing systems always apply this strategy and their selection–evolution mechanisms are based on their ability of growing on any untapped resource available. In order to do so, they increase the number of components and patterns for resource degradation in order to optimize the resource throughput and power output. Such a strategy also applies to human-dominated, economic systems, where the ability of dealing with co-products and wastes by means of appropriate designs as well as reuse and recycling processes may lead to “zero-emission” patterns (increased complexity, optimal resource throughput, minimization of emissions, resource exchange among system's components) and be the key for successful and sustainable development. In this paper Life Cycle Assessment and Emergy Synthesis approaches are suggested as joint tools for qualitative and quantitative evaluation of progresses towards industrial symbiosis and more sustainable production and consumption patterns within a zero emission framework.  相似文献   

6.
安全控制系统与FSC   总被引:3,自引:2,他引:3  
随着社会的发展,人们对生产安全的要求越来越高,本文介绍了安全控制在工业生产,特别是在石油、化工生产中的重要性和安全控制系统从简单到复杂的发展过程,并着重介绍了Honeywell公司生产的故障安全控制系统(FSC-Fail safety control)的特点与应用。  相似文献   

7.
生态系统完整性不仅反映了环境干扰下生态系统维持最优化运作和良性发展的能力,也反映了为人类社会提供有价值产品和服务的能力。本文以生态系统完整性的视角,从耗散结构和生态系统结构、过程、服务功能方面分析了岩溶生态系统的特点,表明岩溶生态系统完整性也是潜在脆弱的,随着生态的逐渐退化,生态系统完整性逐渐损失。作为人类作用胁迫下的终态,岩溶土地石漠化的发生和加剧代表着岩溶生态系统完整性的丧失,石漠化治理及生态恢复过程则是生态系统完整性逐渐恢复的过程。  相似文献   

8.
The terms growth and evolution can as well be applied to unstable physical systems. The ability of instabilities to create visible shape is being investigated. There are innumerable examples of that in the universe. One class occurring in cosmical plasmas results from the localized dissipation of energy stored in strongly sheared magnetic fields. It leads to the appearance of dynamic luminous structures, as for instance in solar flares and in the northern lights.  相似文献   

9.
This review paper presents a brief historical survey of the technological and early research that laid the groundwork for recent advances in sleep–waking research. A major advance in this field occurred shortly after the end of World War II with the discovery of the ascending reticular activating system (ARAS) as the neural source in the brain stem of the waking state. Subsequent research showed that the brain stem activating system produced cortical arousal via two pathways: a dorsal route through the thalamus and a ventral route through the hypothalamus and basal forebrain. The nuclei, pathways, and neurotransmitters that comprise the multiple components of these arousal systems are described. Sleep is now recognized as being composed of two very different states: rapid eye movements (REMs) sleep and non-REM sleep. The major findings on the neural mechanisms that control these two sleep states are presented. This review ends with a discussion of two current views on the function of sleep: to maintain the integrity of the immune system and to enhance memory consolidation.This article is based in part on material in the book The neural control of sleep and waking (J. Siegel, 2002).  相似文献   

10.
采用高效菌提高普通活性污泥系统抗2,4-DCP负荷冲击能力   总被引:7,自引:3,他引:4  
研究了用于处理生活污水的普通活性污泥反应器(CAS)受到2,4-二氯酚(2,4-DCP)间歇性负荷冲击时,投加高效菌的生物强化系统和对照系统对污染物的响应及系统稳定性,并考察了长期运行过程中强化系统对目标污染物去除能力的变化.结果表明,投加5%和15% 2,4-DCP复合高效菌的强化CAS系统,其对目标污染物的降解能力及抗负荷冲击能力得到显著提高.当系统受到间歇性2,4-DCP负荷冲击[110.37~171.60 mg/(L·d)]时,对于单次投菌后前30日内发生的间歇性负荷冲击,强化系统有效保持了对目标污染物的强化效果;在无2,4-DCP存在的情况下连续运行70d,当系统再次受到2,4-DCP负荷冲击时,强化系统的强化效果与前几次相比已明显下降,不能够快速有效去除污染物并维持系统稳定,因此有必要再次投加高效菌.  相似文献   

11.
从泡沫灭火剂的选择、种类特性、取样送检要求、兼容性等几方面对FPSD泡沫灭火系统的有效性进行了研究,旨在从泡沫灭火系统的设计、采办、布局、安装、调试、操作及日常维护等整个生产周期出发,确保FPSO泡沫灭火系统的完整、可用和有效,以期为油田的安全开发提供参考。  相似文献   

12.

The pollination syndrome concept implies that flowers evolved with particular sets of characteristics, such as colors, shapes, orientations, and rewards, as a means of attracting pollinators. However, these traits may have also evolved to deter unwanted visitors. The North American genus Penstemon exhibits a great floral diversity that is mainly associated with bumblebee and hummingbird pollination. Evolutionary shifts from insect pollination to hummingbird pollination have occurred in Penstemon repeatedly, but some species maintain mixed-pollination systems and intermediate floral traits between bee- and hummingbird-pollination modes. The apparently intermediate floral traits of species with mixed-pollination systems might be potentially acting to deter bumblebee foragers. Then, bird-flower traits might be selected with increased hummingbird visitation over evolutionary time might, resulting in specialization to and the evolution of floral traits present in hummingbird-pollinated species. Here, we modified bee-pollination floral traits in Penstemon gentianoides with a mixed pollination system, to resemble hummingbird-pollination traits, and measured the effects of trait modification on bumblebee foraging behavior and plant female reproductive fitness. Our results showed that reduction in the width of the corolla tube and the absence of the corolla lip negatively affects bumblebee visitation and their efficiency as pollinators, and that the synergistic interaction of both traits enhanced the “anti-bee” effect. We conclude that acquisition of floral traits that resemble those of hummingbird-pollination enables Penstemon plant species to deter bumblebee visits.

  相似文献   

13.
建设项目环境监理内涵及要点浅析   总被引:1,自引:0,他引:1  
焦涛 《环境科学与管理》2012,37(5):62-65,77
建设项目环境监理是建设项目环评和"三同时"验收监管的重要辅助手段,对强化建设项目全过程管理、提升环评有效性和完善性具有积极作用,但环境监理工作总体尚处于试点阶段,对环境监理的定位、作用和范围不够明确。本文从建设项目环境监理相关术语、工作流程、工作制度及方法分析了建设项目环境监理内涵,并分工业类和生态类项目介绍了环境监理要点,为相关部门和单位开展建设项目环境监理工作提供指导和依据。  相似文献   

14.
海岛是相对独立的地理单元,生态系统较为脆弱,旅游开发将对海岛带来环境影响.为保护和利用海岛的旅游资源和自然环境,以蜈支洲岛旅游开发为例,采用矩阵法识别海岛开发生态影响因子,建立了水土流失、土壤、沙滩、植被、保护动植物、珊瑚、珊瑚生态、景观等评价指标体系,采用模型预测和类比分析等方法预测、分析和评价旅游开发活动的生态影响,并提出减缓对策,从而避免旅游开发造成岛屿的生态破坏,维护岛屿生态系统的完整性.  相似文献   

15.
水生态系统完整性研究是当今国际热点,维护水生态系统健康与稳定已成为世界各国水生态系统保护的目标、方向和管理策略. “十三五”以来,我国地表水环境质量改善效果显著,但部分流域或局部水生态退化问题成为突出短板,强调水生态系统整体保护、促进水生态环境质量全面改善、提高生态系统自我修复能力将是未来我国水生态环境保护的重点任务. 本文详细剖析了典型流域水生态系统保护现状和需求,阐述了我国开展水生态系统完整性研究的重大意义,系统总结了完整性研究国际进展和应用实践,深入分析了当前我国完整性研究面临的主要挑战,提出了未来发展思路与重点任务. 加快研发完整性监测与评价新技术,建立物理、化学和水生生物多要素统筹的完整性评价指标体系,创新发展多尺度完整性评价理论,持续开展典型流域完整性状况评估,摸清水生态家底及演变趋势;突破完整性退化诊断与修复调控新技术,厘清退化机制及驱动因子,阐明气候变化与人类活动复杂压力下退化水生态系统修复路径和调控策略,提升水生态系统保护修复的科学性,加快推动我国水生态环境管理制度迈上新台阶,为恢复和维持重点流域水生态系统原真性和完整性提供科技支撑.   相似文献   

16.
It is now widely accepted that climate change is happening and that future changes will impact on many aspects of society, including agriculture. To maintain food supplies, the agricultural industry must address climate change adaptation. Key to this is the attitudes of those within the industry likely to have responsibility for adapting. This study investigated stakeholder attitudes towards adaptation to climate change in the livestock industry. Findings reveal four attitudinal groups. First, there is a ‘farmer-focused group’ that has a positive attitude about the ability of livestock farmers to adapt to climate change, but that also has the opinion that they will need additional support to adapt. Second, there is an ‘incentive for enterprise, anti-GM (genetic modification) group’ with an attitudinal position stressing that the government should have a role in implementing regulations and providing finance. This group has a negative attitude towards GM technology and does not think it will be the answer to climate change. Third, there is an ‘information and education group’ whose attitude is that the provision of information is crucial for ensuring that the livestock industry adapts. Fourth, there is a ‘pro-technology group’ who have a positive attitude towards GM technology and who are therefore willing to embrace it as the route to adaptation. Three of these four groups favour soft adaptations that maintain flexibility within the system, and only the fourth is of the opinion that adaptive capacity is not an issue and that the industry is ready to implement hard adaptations.  相似文献   

17.
李平星  陈雯  邹露  蔡希 《环境科学学报》2021,41(10):3905-3915
区域一体化发展背景下,一体化生态空间格局的构建及其生态环境效应评估兼具丰富生态系统完整性和关联性研究的理论价值、指导生态空间跨区域协同保护的现实意义.以长三角一体化区域为案例,基于生态系统完整性和关联性,开展生态过程模拟和潜在生态廊道识别研究,构建跨区域、一体化的生态空间格局;基于2000—2018年土地利用数据,解析生态空间格局的土地利用/覆被变化(LUCC),核算生态空间格局的生态环境效应及其变化,分析污染物排放与生态环境质量的关系.结果表明,长三角地区的潜在生态廊道和一体化生态空间格局涵盖大部分城市,并主要分布在江苏沿江、安徽南部和浙江东南部地区;生态空间格局内生态用地占据主导,建设用地有缓慢增长的态势,导致生态环境质量有所降低;浙江东南部、安徽南部城市生态环境质量较高,且保持相对稳定;生态廊道内部缓冲区的生态环境质量较高,适合作为构建一体化生态空间格局、维护区域生态安全的主要载体;污染物排放与一体化生态空间的生态环境质量存在一定负相关关系,未来需要采取针对性措施以同步促进污染物减排和提升生态环境质量.  相似文献   

18.
Primate males have only recently returned to the center stage of socioecological research. This review surveys new studies that examine variation in the behavior of adult males and their role in social evolution. It is shown that group size, composition, and social behavior are determined not only by resource distribution, predation risk, and other ecological factors, but that life history traits and social factors, especially those related to sexual coercion, can have equally profound consequences for social systems. This general point is illustrated by examining male behavior at three levels: the evolution of permanent associations between males and females, the causes and consequences of variation in the number of males between group-living species, and the determinants of social relationships within and between the sexes. Direct and indirect evidence reviewed in connection with all three questions indicates that the risk of infanticide has been a pervasive force in primate social evolution. Several areas are identified for future research on male life histories that should contribute to a better understanding of male reproductive strategies and corresponding female counter-strategies.  相似文献   

19.
Parasite-mediated selection may affect the evolution of cognitive abilities because parasites may influence development of the brain, but also learning capacity. Here, we tested some predictions of this hypothesis by analyzing the relationship between complex behaviours (feeding innovations (as a measure of behavioural flexibility) and ability to detect foreign eggs in their nests (i.e. a measure of discriminatory ability)) and abundance of microorganisms in different species of birds. A positive relationship would be predicted if these cognitive abilities implied a larger number of visited environments, while if these skills favoured detection and avoidance of risky environments, a negative relationship would be the prediction. Bacterial loads of eggshells, estimated for mesophilic and potentially pathogenic bacteria (i.e. Enterococcus, Staphylococcus and Enterobacteriaceae), were used as a surrogate of probability of contact with pathogenic bacteria. We found that bird species with higher feeding innovation rates and rejection rates of experimental brood parasitic eggs had higher density of bacteria on their eggshells than the average species. Since the analysed groups of microorganisms include pathogenic bacteria, these results suggest that both feeding innovation and ability to recognize foreign eggs are costly and highlight the importance of parasite-mediated selection in explaining the evolution of cognitive abilities in animals.  相似文献   

20.
Interest in bioenergy is growing across the Western world in response to mounting concerns about climate change. There is a risk of depletion of soil carbon stocks in biomass production systems, because a higher proportion of the organic matter and nutrients are removed from the site, compared with conventional agricultural and forestry systems. This paper reviews the factors that influence soil carbon dynamics in bioenergy systems, and utilises the model FullCAM to investigate the likely magnitude of soil carbon change where bioenergy systems replace conventional land uses. Environmental and management factors govern the magnitude and direction of change. Soil C losses are most likely where soil C is initially high, such as where improved pasture is converted to biomass production. Bioenergy systems are likely to enhance soil C where these replace conventional cropping, as intensively cropped soils are generally depleted in soil C. Measures that enhance soil C include maintenance of productivity through application of fertilisers, inclusion of legumes, and retention of nutrient-rich foliage on-site. Modelling results demonstrate that loss of soil carbon in bioenergy systems is associated with declines in the resistant plant matter and humified soil C pools. However, published experimental data and modelling results indicate that total soil C loss in bioenergy systems is generally small. Thus, although there may be some decline in soil carbon associated with biomass production, this is negligible in comparison with the contribution of bioenergy systems towards greenhouse mitigation through avoided fossil fuel emissions.  相似文献   

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