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We examined electrophoretic variation in the supralittoral gastropod,Nodilittorina africana knysnaensis, along the coast of South Africa in 1989. There was little allozyme variation in nine samples collected over 1 500 km for three highly polymorphic loci,Est, Gpi, andPgm, and Wahlund's effect was absent in the pooled sample. A gene diversity analysis showed that 98.1% of total genic diversity, on average, was contained within populations, and that only 1.9% was due to allozyme frequency differences among populations. Since the mode of larval development has not yet been described for this species, we suggest that the lack of strong allozyme frequency differences over long distances indicates thatN. a. knysnaensis has a planktonic mode of larval development. 相似文献
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The Science of Nature - 相似文献
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Vertical distribution of polycyclic aromatic hydrocarbons in atmospheric boundary layer of Beijing in winter 总被引:1,自引:0,他引:1
Shu Tao Yi Wang Shiming Wu Shuzheng Liu Han Dou Yanan Liu Chang Lang Fei Hu Baoshan Xing 《Atmospheric environment (Oxford, England : 1994)》2007,41(40):9594-9602
Air samples were collected using active samplers at various heights of 8, 15, 32, 47, 65, 80, 102, 120, 140, 160, 180, 200, 240, 280 and 320 m on a meteorological tower in an urban area of Beijing in two campaigns in winter 2006. Altitudinal distributions of polycyclic aromatic hydrocarbons (PAHs) in atmospheric boundary layer of Beijing in winter season were investigated. Meteorological conditions during the studied period were characterized by online measurements of four meteorological parameters as well as trajectory calculation. The mean total concentrations of 15 PAHs except naphthalene of gaseous and particulate phase were 667±450 and 331±144 ng m−3 in January and 61±19 and 29±6 ng m−3 in March, respectively. Domestic coal combustion and vehicle emission were the dominant PAH sources in winter. Although the composition profiles derived from the two campaigns were similar, the concentrations were different by one order of magnitude. The higher concentrations in January were partly caused by higher emission due to colder weather than March. Moreover, weak wind, passing through the city center before the sampling site, picked up more contaminants on the way and provided unfavorable dispersion condition in January. For both campaigns, PAH concentrations decreased with heights because of ground-level emission and unfavorable dispersion conditions in winter. The concentration ratio of PAHs in gas versus solid phases was temperature dependent and negatively correlated to their octanol–air partition coefficients. 相似文献
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应用发光菌测定有机化合物的毒性 总被引:11,自引:4,他引:11
本文介绍了化合物对发光菌半数抑制发光强度的毒性测定方法,测定了几十种芳烃类化合物的毒性,发现不同取代基或取代位置的芳烃毒性不同,并且对发光菌的毒性与对黑呆头鱼的毒性有相关性。 相似文献
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