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1.
南京城市西部历史时期是城市的重要边界,现在逐渐演变成老城与新区之间的核心地带,成为公共活动的重要地区,保护其自然、文化遗产和生态环境具有非常重要的意义。在对其现状调查分析的基础上,梳理遗产点的历史概况、现状及其分布情况,提出规划遗产廊道的意义,探讨规划的具体思路,为南京遗产保护提供了新的视角。  相似文献   

2.
The induction of metamorphosis in mature larvae by selected chemical compounds and natural substrata was investigated in two species of sea urchins from the Sea of Japan, Strongylocentrotus intermedius and Scaphechinus mirabilis. Glutamine in crystalline form was added directly to water containing mature larvae, and this compound, at a final concentration of 10 g ml-1, was an inducer of metamorphosis in S. intermedius (100% activity) and S. mirabilis (50% activity). Gutamine, or its natural mimetic molecules, may be an active component of the exogenous cue that induces metamorphosis of S. intermedius larvae. This exogenous cue was produced by the epiphytic calcareous algae, Melobesia spp. that colonized the older sea grass Zostera marina. Glutamic acid was also used as an inducer of metamorphosis for S. intermedius and S. mirabilis larvae (50 to 60% activity), but it was toxic to the larvae.  相似文献   

3.
目前常用降水量乘以降水入渗补给系数的方法计算降水入渗补给量,此法不能表现降水特征、蒸发等因素对降水入渗补给的影响.为解决不同时间尺度、不同降水特征和蒸发情况下的降水入渗补给量,在分析郑州地下水均衡试验场地中渗透仪实测入渗量、降水和蒸发资料的基础上,利用均匀设计法选取最优的与降水入渗补给量关系密切的前期降水量和蒸发量的期次,然后利用回归分析建立各岩性和埋深的年、月和日尺度上的降水入渗函数,可以比较准确的计算降水入渗补给量.表3,参9.  相似文献   

4.
洞庭湖生态环境承载力分析   总被引:3,自引:1,他引:3  
姜加虎  黄群 《生态环境》2004,13(3):354-357
洞庭湖湖内冬枯水季节,有芦苇面积530km^2,草地面积800余km^2,泥滩地面积367km^2,天然水域面积约993km^2。湖洲之间隔水相望,河沟水系纵横交错,具“水浸皆湖,水落为洲”的地貌特征,呈现出支离破碎的形态面貌和典型的自然湿地景观。文章在大量调查的基础上,从自然和人文两个方面对洞庭湖的生态环境承载力或环境压力进行分析。  相似文献   

5.
Adsorption potential of a commercial activated carbon (FS300) has been evaluated for the uptake of cationic dyes namely methylene blue (MB) and rhodamine B (RB). Though, there are numerous studies in literature which report the sorption of MB (more than 40 studies) and RB (more than 10), however none of these use a common parameter to report the capacity of the sorbent. A protocol, based on the equilibrium dye concentration has been proposed to measure the sorption potential of a sorbent. The Langmuir model can very well describe the experimental equilibrium data for both dyes (coefficient of correlation > 0.999). MB (Qm = 312.5 mg g(-1)) is more adsorbable than the RB (Qm = 144.9 mg g(-1)). Molecular weight and chemical structure of dye molecules seem to affect the dye uptake. The effect of pH on dye uptake has also been evaluated by varyingpH from 3 to 11. Uptake of MB increases with pH, wherein RB removal decreases with pH. Dyes could not be desorbed either by distilled water (0.06 and 0.11% for MB and RB respectively), or by 0.1 NHCl (0.136 and 3.0% for MB and RB respectively) indicating, chemical adsorption type of adsorbent-adsorbate interactions.  相似文献   

6.
以广东省西部不同地区的三种不同类型的红土:赤红壤、黄壤、砖红壤为例,研究了这些红土土壤的光谱反射特性,进行了光谱波形特征及一些吸收波段特征的分析,对这三种土壤的光谱特征进行了对照比较,并且对土壤的各个剖面层的光谱差异进行了分析.结果表明,三种土壤其光谱特征基本相似,都是属于"陡坎型".氧化铁的吸收波段明显.并且整个波谱曲线的反射率都比较低.但是不同红土的光谱又有各自的特性.不同母岩发育的同一类土壤及其同一个土壤不同的剖面层都因为有机质、氧化铁等的含量不同其反射率曲线有一定的差异.玄武岩发育的砖红壤的反射率曲线比较平直些,曲线的反射率更低,这意味着玄武岩发育的砖红壤中比花岗岩等其他母质发育的赤红壤和黄壤富含更多的铁铝三氧化物.这些分析结果可能为这些类别红土的识别和分类提供诊断指标.  相似文献   

7.
The effects of temperature, salinity and oxygen tension on the rates of oxygen consumption of three different strains of Artemia nauplii have been studied. When acclimated to a salinity of 30, nauplii from each of the three strains were able to maintain approximately constant rates of oxygen consumption over a wide range of oxygen tension. The ability to maintain respiratory independence during hypoxia was reduced, however, with an increase in either temperature or salinity. Nauplii of two of the strains (parthenogenetic diploid and tetraploid) showed a progressive increase in the rate of oxygen consumption with increasing temperature up to 35°C. Nauplii of the bisexual strain appeared to be less tolerant of exposure to temperatures >30°C, since at higher temperatures their oxygen consumption declined slightly. The differences between the nauplii of the different strains in their physiological responses to changing environmental conditions appear to correlate well with their seasonal occurrence in the field.  相似文献   

8.
城市污泥超声波处理技术   总被引:14,自引:0,他引:14  
较全面的介绍了超声波处理污泥的效果,以及目前取得的研究进展,并简要讨论了今后的发展趋势。在适当的操作条件下,超声波可以迅速改变污泥结构,释放菌胶团包含水,从而促进污泥减量化和稳定化。高强度的处理也可以加快污泥水解、提高污泥可生化性、提高沼气产量。同时可消毒有害病菌。  相似文献   

9.
不同饲粮对生猪产污情况的影响   总被引:2,自引:0,他引:2  
研究了精饲料和精青配合饲料饲养下育肥猪排污量和主要污染物含量的差异.结果表明,与饲喂精饲料相比,饲喂精青配合饲料的生猪产粪量降低18.97%,产尿量降低38.56%.精饲料饲养50d后,生猪体质量仅比精青配合饲料饲养平均增加1.5kg,采用精青配合饲料饲养的生猪体质量每增加lkg饲料成本投入比精饲料饲养减少21.68%.精青配合饲料喂养生猪不仅可减少污染物的排放量,还可节约饲料投入成本,提高养猪效益.  相似文献   

10.
In this study, China’s current macro-environmental policies as well as their implementation and management tools are analyzed. By using the basic economic methodology, detailed studies are conducted focusing on the implementation effect of contemporary China’s typical environmental policy of the total pollutant discharge quantity control type, and also the two types of environmental management tools are compared from the perspective of implementation costs and policy uncertainty. By introduction of distributed management tools into the implementation of environmental policies, market-oriented means and the methods of economic analysis are introduced into environmental policy decision-making mechanisms, which could afford a new method for changing the current relatively low efficiency of environmental policy, solving the problem of “government failure” in environmental policy implementation, and providing a new way to make environmental policy system more flexible and more efficient. It is of great practical significance to solve China's current structural, complex and accumulative environmental problems.  相似文献   

11.
基于RS和GIS的嫩江下游土地沙漠化景观格局变化特征分析   总被引:1,自引:0,他引:1  
以2004、2008年的MODIS数据为主要数据源,在ArcGIS 9.0、ERDAS IMAGE 9.0等软件支持下,利用FRAGSTATS软件分析土地沙漠化的景观格局变化.结果表明,研究区域沙漠化土地以轻度和中度沙漠化土地为主;各景观要素的边缘密度和斑块密度呈现一致性的减少,表明斑块形状趋向简单,景观整体破碎化程度降低,边缘效应影响减小;除水域景观外,其他景观要素的形状指数和分维数都呈现一致性的下降,表明整体景观的形状都向着简单化和稳定性方向发展,各景观要素的散布与并列指数和聚集度指数都呈现一致性的增加,反映出各要素斑块趋向大型化发展,景观整体连接度增强,破碎化程度降低,景观相互作用和空间关系增强.  相似文献   

12.
论现阶段我国城市化的道路选择及政策取向   总被引:3,自引:0,他引:3  
通过我国城市化现状的分析,结合我国具体国情,具体提出相当一段时期内我国城市化道路的选择:大、中、小不同城市协调发展、整体推进;东、中、西不同经济发展地带区别对待,体现层次.同时,还要求相应的政策、制度、法规等及时跟上,加快城市化步伐.  相似文献   

13.
M. G. Hoskin 《Marine Biology》1997,127(4):647-656
 In south-eastern Australia, the prosobranch gastropods Morula marginalba (Blainville), Cominella lineolata (Lamarck) and Bedeva hanleyi (Angas) have similar fine-scale distributions, but appear to possess very different dispersal capabilities due to contrasting modes of larval development. M.marginalba produce planktonic larvae, whereas C. lineolata and B. hanleyi undergo direct development in benthic egg capsules and emerge as crawling juveniles. To test for possible effects of contrasting life histories on levels of genetic variation within and among populations, a survey was conducted of allozyme variation at six polymorphic loci in 8 to 9 local populations of each species. Collections of snails were made between June 1992 and November 1993. Sampling ranges spanned between 162 and 180 km of coast. Regardless of larval type, proportions of single-locus genotypes in each collection were consistent with the recruitment of offspring which had been generated through random mating. However, genotypic diversity was lower in those species that undergo direct development. Loci surveyed in C. lineolata and B. hanleyi were polymorphic (i.e. frequency of most common allele <95%) in fewer populations than those examined for M.␣marginalba (P <0.001) and, where polymorphisms occurred, also possessed significantly fewer alleles (P <0.001). Consequently, average levels of expected heterozygosity were greater in populations of M. marginalba than in those of either of the other species (P <0.001). Genetic variation among populations, expressed as the standardised variance in allele frequencies (F ST ), was inversely related to expected larval dispersal capability. The nine collections of M. marginalba showed little overall differentiation (F ST  = 0.017; P <0.001), reflecting the ability of planktonic larvae to interconnect local populations, and so limit divergence due to drift and natural selection. In contrast, there were high levels of allelic heterogeneity among the nine collections of C. lineolata (F ST  = 0.523; P <0.001) and eight collections of B. hanleyi (F ST  = 0.140; P <0.001). These data imply that for species which undergo direct development, local populations are effectively closed and evolve largely independent of one another. Received: 3 May 1996 / Accepted: 12 July 1996  相似文献   

14.
Three main enzymes, responsible for bioconversion of 1,3 dinitrobenzene (m-DNB) by Micrococcus colpogenes MCM B 410, were isolated from the sonicated cell mass, grown in presence of m-DNB in a synthetic medium, for 7 days. The soluble proteins were separated by differential precipitation and also separated by native PAGE. Each fraction obtained from both the protocols, was tested for nitro aryl reductase, aryl mono oxygenase and resorcinol 2,3 dioxygenase. The apparent molecular weight of the proteins were nitro aryl reductase (30 kDa), aryl mono oxygenase (110 kDa) and resorcinol 2,3 di oxygenase (65 kDa).  相似文献   

15.
为优化核桃试管苗生长条件,向核桃优良品种规模化栽培提供大量优良的种植材料,以‘香玲’核桃实生苗为材料,对基本培养基的类型(MS,DKW,WPM)和凝固剂种类(琼脂,Phytagel,二者结合)进行了筛选,并采用完全随机试验设计研究了细胞分裂素种类和浓度对其试管苗生长的影响.试验结果表明:基本培养基与凝固剂的种类,以及细胞分裂素的种类与浓度对芽苗生长的影响很大.以DKW为基本培养基,2.2 g/L Phytagel为凝固剂,激素配比为0.8 mg/L BA+0.01 mg/L IBA,有利于芽苗增殖,增殖可达4.70;后在0.8 mg/L KT+0.01 mg/L IBA进行壮苗,即可进行生根培养.不同基因型对基本培养基中无机盐成分的需求不同,含有较丰富矿物质的Phytagel有利于芽苗生长.BA促进腋芽的萌动和增殖,而KT则有利于壮苗.图4表3参22  相似文献   

16.
 Certain criteria must be satisfied before a licence for the deposition of dredged material at sea in UK waters is issued. These relate to the chemical quality of the material, the quantity to be disposed of, its nature and origin, and its predicted impacts at the disposal site. Although chemical analyses of dredgings provide an indication of the relative degrees of contamination, they do not provide a measure of any resultant biological effects. A laboratory experiment was therefore designed to investigate the effects of the degree of contamination and the role of burial associated with the deposition of dredged material on the meiofauna. Estuarine nematode assemblages were exposed to the simulated deposition of uncontaminated, oxic intertidal mud and anoxic sediments from the Mersey and the Tees estuaries, both of which were contaminated with heavy metals. The sediments, which differed little in terms of grain size, were deposited in two different frequencies. Nematodes showed a clear species-specific response to the experimental treatments, depending on the frequency of deposition and the chemical quality of the deposited material (e.g. metal and oxygen concentrations). The response of nematode assemblages was mainly determined by the deposition frequency rather than the type of sediment or the degree of contamination. The deposition of sediment in one large dose at the beginning of the experiment caused more severe changes in assemblage structure than the same quantity deposited in several smaller doses. Although lower than in uncontaminated mud, relatively high migration and survival rates in the contaminated high-frequency treatments were observed. This may have been due to reduced bioavailability of metals and the tolerance of estuarine nematodes to both metal contamination and the deposition of small sediment volumes at regular intervals. The observed trends demonstrate the potential of small-scale laboratory experiments for testing the quality of contaminated dredged material at the licensing stage, i.e. prior to the issue of a disposal licence. Received: 11 February 2000 / Accepted: 26 June 2000  相似文献   

17.
Back in 1992, the Gulf of Aqaba Environmental Action Plan (GAEAP), a collaboration between the Aqaba Region Authority (ARA), Jordan and the World Bank, gave considerable emphasis to the environmental protection of the Gulf of Aqaba [The World Bank. Gulf of Aqaba Environmental Action Plan. Report No. 12244JO (1993).]. The document recommended the establishment of a marine reserve and the long term monitoring of the coastal habitats' environmental quality. The combination of a dedicated follow up, the collaborative efforts of ARA and the Marine Science Station (MSS), and the founding of the Aqaba Special Economic Zone Authority (ASEZA) have turned the recommendations into reality. A comprehensive monitoring program of the Jordanian coastal habitats commenced in 1999. The first three years of the program were financed by a donation from The Global Environmental Facility (GEF). In return, Jordan has committed itself to the maintenance of the monitoring program as an ongoing tool for sustainable coastal management. The monitoring program includes observations on benthic habitat, fish communities, bottom sediments and seawater quality. This paper focuses on the results of seawater-quality monitoring in the first three years. Records of weather conditions, coastal currents, seawater temperature, transparency, salinity, density, pH, alkalinity, dissolved oxygen, ammonia, nitrate, nitrite, phosphate, silicate, particulate matter, chlorophyll a, zooplankton biomass, total coliform, fecal coliform, hydrocarbons and sedimentation rate have been generated monthly since January 1999 at six coastal stations, and one offshore reference station, in the Jordanian waters of the Gulf of Aqaba. The coastal stations are located at sites with different benthic habitats and are occupied by different human activities. Offshore records of density (thermohaline structure), nutrients and chlorophyll a depicted two well-defined seasons; a nutrient-/chlorophyll a-rich, mixed water winter from December to April and a nutrient-/chlorophyll a-poor, stratified water summer from June to October. Short transition seasons appeared in May and November. The mixing and stratification seasons were also clearly depicted in the coastal waters. Statistical analysis of the three-year data collected at the offshore station revealed no significant inter-annual differences in the upper 125 m of the water column with respect to any of the measured parameters. At coastal stations, the water quality at the two northernmost stations was significantly different in comparison to the upper 125 m at the offshore station and to the other coastal stations, with respect to the two key indicator parameters: inorganic nitrogen and chlorophyll a. The three-year findings of the monitoring program are employed to suggest standard codes of reference for the coastal water quality.  相似文献   

18.
南京市生态足迹实证分析   总被引:2,自引:0,他引:2  
利用生态足迹的理论和计算方法,对南京市可持续发展状况及程度进行了评价和度量,利用南京市2001年至2003年的相关数据计算分析得出,南京市的人均生态承载力在逐年下降,人均生态足迹也有增加的趋势,尤其是能源消费生态足迹在近3年的生态足迹中仍然占有很大的比重,南京目前的经济发展是以消耗其他区域的自然资源和能源为基础的,其所面临的生态环境压力仍然很严重。  相似文献   

19.
不同温度对沉水植物保护酶活性的影响   总被引:3,自引:0,他引:3  
富营养化导致了湖泊沉水植被消亡,是我国众多湖泊存在的普遍现象.在富营养化未能有效控制的前提下,采用人工措施重建沉水植被,已被水环境工作者普遍关注.然而,受水体温度、透明度、营养盐以及适宜的物种等限制,沉水植被的有效重建面临诸多困难.本研究着眼于温度对沉水植被重建的影响,设置了5、10、15、25、30、35℃6个温度处理,在人工气候箱培养条件下,对黑藻Hydrilla verticillata和马来眼子菜Potamogeton malaianus在5 h、10h、14h和7d处理后的蛋白质含量、过氧化物酶(POD)、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性进行了测试.同时考察了实验前后植物生物量积累的情况,比较了不同温度胁迫下,两种植物生物量的净积累与抗氧化酶活性和可溶性蛋白含量的关系,试图为沉水植被的恢复提供理论依据和经验借鉴.结果表明,25℃是两种植物生物量净积累的最佳温度,此温度下,各种酶活性和可溶性蛋白未随处理时间的延长而显著变化.高于或低于25℃的处理,生物量净积累显著下降.并且,表现为短期胁迫5~14h内,各种酶活性和可溶性蛋白随处理时间的延长呈上升或下降的趋势,7 d长期胁迫后上述指标均低于25℃处理.结果表明,25℃外,其它处理均不同程度受到了温度的胁迫.短期胁迫,各处理的酶活性和可溶性蛋白表现了激烈的响应,以清除和维持植物体内活性氧的平衡和植物细胞较低的渗透势,保持植物正常的代谢活动.随着胁迫时间的延续,抗氧化酶系统受损,可溶性蛋白降低,植物正常的代谢紊乱,最终导致实验结束时,各处理植物生物量的积累存在较大差异.  相似文献   

20.
五爪金龙凋落叶腐解物的化感潜力研究   总被引:8,自引:0,他引:8  
采用莴苣种子为受体,测试了五爪金龙凋落叶早期腐解物的化感作用,并与其鲜叶及凋落叶的化感潜力进行了比较分析。结果如下:凋落叶40d的腐解物、鲜叶及凋落叶的水提取液均具有较强的化感潜力,并表现出低促高抑的浓度效应,在FW0.1g﹒mL-1高质量浓度下的综合化感抑制强度为凋落叶未能加土壤的腐解物>鲜叶>凋落叶加土壤的腐解物>凋落叶,而在FW0.005g﹒mL-1低质量浓度下的综合化感促进作用是凋落叶>鲜叶>凋落叶加土壤的腐解物>凋落叶未加土壤的腐解物。鲜叶的抑制强度较凋落叶的大,表明叶片在衰老过程中抑制作用减弱。凋落叶未加土壤仅在空气微生物作用下的腐解物抑制作用最强,促进作用最小,而加入土壤后在土壤微生物作用下的腐解物的抑制作用却有所减弱,抑制强度介于鲜叶和凋落叶的之间,促进作用却小于鲜叶和凋落叶,说明凋落叶腐解过程中微生物的参与对化感作用产生了复杂的影响。  相似文献   

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