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41.
Population characteristics, individual life-history variables, feeding and vertical distribution of the mesopelagic fish Müller's pearlside Maurolicus muelleri collected in 1990 in Masfjorden, western Norway, are reported as well as environmental variables from the fjord. Minimum size at maturity was far smaller than reported from previous investigations in the same region. Fecundity was size-dependent and total egg numbers were higher than reported from other investigations of M. muelleri world wide, while the number of maturing eggs was far lower than observed in the same region earlier. Food concentration in the fjord was an order of magnitude lower than previous early summer observations, and several factors indicated that feeding opportunities may have been low for a long period. Daily feeding rate (g prey g-1 fish) decreased with increasing fish size. These observations fit well with a model of maximizing fitness by means of a flexible size at maturity. Minimum age at maturity seems to be achieved at the expense of fecundity. M. muelleri was concentrated in a 20 to 30 m deep sound scattering layer (SSL). The SSL stayed close to the surface during the night and at 100 to 180 m during the daytime. The vertical position of the SSL varied instantaneously with changes in surface light intensity, remaining at 10-3 to 10-4 mol m-1 s-1 at the top of the SSL. Stomach fullness was highest during the night; feeding intensity seems to have been peaked at dusk. Cladocerans were the main prey ranked by number, copepods by biomass. Intake of large copepods increased with fish size. 相似文献
42.
Comparison of allozyme and mitochondrial DNA spatial differentiation in the limpet Patella vulgata 总被引:2,自引:0,他引:2
Allozyme and restriction enzyme analysis of mtDNA was used to study variation in samples from British populations of the marine limpet Patella vulgata in two regions. South Wales and Northeast England. Allozyme analysis revealed significant differences in allele frequencies among samples. However F
ST
(population differentiation) values were no higher between than within regions, indicating that genetic heterogeneity was localised and not related to geographic separation. For mtDNA, samples from South Wales exhibited higher haplotype diversity values than samples from Northeast England. In addition there were substantial differences in the haplotype distribution between regions. The value of , the haploid analogoue of F
ST
, was low within regions (=0.09) but high between regions (=0.44). The estimated difference in migration rate for allozymes and mtDNA exceed the neutral expectation, unless it is assumed that there are influential differences in the magnitude of female and male gametic dispersal. 相似文献
43.
J. Altenburger Th. Dielacher P. Eder H. Ferner M. Fegerl J. Fresner O. Gelinek A. Kogler J. Jantschgi M. Nussbaumer B. Russegger H. Schnitzer K. Schauer B. Sebesta J. Seiler F. Sprenger H. Widenmeyer 《Journal of Cleaner Production》1994,2(3-4)
The paper focuses upon the organization of a federal state-funded pollution prevention project in the Styrian industry. The project includes 13 companies from the textile, pulp and paper, machine building, wood working and printed circuit board manufacturing industries, covering most of the sectors and sizes in the Styrian industry. It started in January 1994 and will last for one year. It will demonstrate the possibilities of pollution prevention and the need for further research work. This project will make use of the methods and tools that were refined in the Austrian Prepare project. As a first step, a systematic balance of all the inputs and outputs of a company is made, after which the weak points and inefficiencies of material and energy use are identified and the options for improvements, both economical and ecological, are defined. Consequently, modifications in products and production lead to a situation with less waste and emissions. The preliminary lessons from these projects are presented: as a rule, the utilities (consumption of process materials and water, cleaning, energy, preparatory and finishing steps) are treated as black boxes and usually represent a considerable optimization potential. In these areas especially there is usually a lack of information and coordination as well as a need for a systematic and comprehensive approach. Leadership in the company and creative consultants are needed for starting lasting successful pollution prevention projects. 相似文献
44.
Ma Shijun 《环境科学学报(英文版)》1990,2(2):57-62
This paper concisely introduced the eco-environmental survey in China and the Chinese scientific programme for environmental research which is being practiced or being planned. China has established a nation-wide system relating to environmental scientific research and environmental administration and has taken the following strategies for solving the environment problems: (1) a series of laws and regulations for environmental protection has been promulgated so as to strengthen the legal administration and economic punishment. (2) the idea of ecological construction has been proposed for the purpose of taking the environmental protection work into the consideration of the national and provincial (or regional) economic construction planning. (3) spreading ecological engineering and ecological technologies have reduced the pollutant sources and have increased the industrial and agricultural economic profit. 相似文献
45.
基于AHP-MF模型的用户群节水指标体系研究 总被引:1,自引:0,他引:1
从分析影响用户群节水的因素及其构成关系入手,根据专家长期节水工作的经验,利用层次分析法对用户群节水指标进行优选,并提出全面的定量化和定性化的层次结构评价模式和总体评价方法.首先构建用户群节水的层次分析结构模型及判断矩阵,应用Matlab6.5计算出各判断矩阵的最大特征值及其特征向量,并检验判断矩阵的一致性,继而确定出各指标的权重;其次,应用Fuzzy统计的方法对陕西2006年度高校用户群的节水情况进行评价,并为节水工作提供建设性意见. 相似文献
46.
锦州湾表层沉积物中铅、锌、镉在各地球化学相间的分配规律 总被引:3,自引:0,他引:3
研究了受重金属严重污染的锦州湾内表层沉积物中铅、锌、镉在各地球化学相间的含量,及其在湾内河水-海水混合界面附近各相间的迁移转化特征。结果表明,锦州湾表层沉积物中上述重金属以非残渣相为主要存在形式,其中铁锰氧化物为重要的清除载体;以铁锰氧化物和碳酸盐形式存在的重金属含量由水环境的E_H和pH控制;在污染源附近的海区,表层沉积物中重金属在非残渣相和残渣相间的比值与近岸锌厂排出的这些重金属在废水和废渣中的含量比呈正相关关系。 相似文献
47.
E. Lamla F. Boschke G. Traving G. Pfotzer H. Wolter W. Walcher H. D. Dahmen H. J. Queisser W. W. Klingbeil K. Beyermann O. Müller R. R. Ernst D. Reinen H. Muth W. Becker G. Wunsch G. I. Distler L. Jaenicke H. G. v. Schnering H. Werner F. Reiff H. Schimassek W. Höll H. K. Vasil W. F. Angermeier W. Ruppel J. C. Eccles G. Spiteller H. Oettel W. Vogell P. Brosche K. J. Hsü H. -U. Schmincke 《Die Naturwissenschaften》1975,62(3):143-143
48.
49.
James Gitundu Kairo Farid Dahdouh-Guebas Patrick O.Gwada Catrick O.Gwada Nico Koedam 《Ambio-人类环境杂志》2002,31(8)
本文研究了米达河(南纬3°20',东经40°00')两个红树林森林地区(乌永博和基雷普维)带状横断面的红树林植被的结构和恢复型式. 相似文献
50.
环境保护与公众参与--绿色中国第九届论坛在京隆重召开 总被引:1,自引:0,他引:1
以“环境保护与公众参与”为主题的第九届“绿色中国论坛”,于12月3日在北京昆仑饭店隆重召开,这是2005中国环境文化节的重头戏。全国人大副委员长许嘉璐、全国政协副主席陈奎元.中宣部副部长胡振民.全国政协人资环委副主任温克刚等领导同志。来自清华大学.中国政法大学等著名高校的知名专家学者和企业家代表.文化界代表。以及全国70多家环保组织负责人应邀到会。国家环保总局副局长潘岳主持了论坛开幕式。并致开幕词。潘岳副局长还邀请中宣部副部长欧阳坚为本次论坛致词。本刊精编了论坛上的精彩发言,在此与读者共同分享。[编者按] 相似文献