排序方式: 共有17条查询结果,搜索用时 218 毫秒
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A fire at a chemical manufacturing plant at Schweizerhalle (near Basel) in November 1986 and the subsequent release of toxic agrochemicals into the Rhine river is taken as a basis to discuss some problems and needs in ecotoxicological research. Especially serious is the lack of knowledge about chronic effects of mixtures of chemicals to individuals and whole ecosystems. There is an urgent need for generally applicable principles and concepts. A discussion of the relationship between toxic effects to fish, exposure time, and concentration provides some hints about the direction towards which research should proceed. Finally, eight theses pertaining to ecotoxicology summarize what can be learned from the analysis of a chemical spill. 相似文献
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Markus Stumm Michael Entezami Karsten Haug Cornelia Blank Max Wüstemann Bernt Schulze Gisela Raabe-Meyer Maja Hempel Markus Schelling Eva Ostermayer Sabine Langer-Freitag Tilo Burkhardt Roland Zimmermann Tina Schleicher Bernd Weil Ulrike Schöck Patricia Smerdka Sebastian Grömminger Yadhu Kumar Wera Hofmann 《黑龙江环境通报》2014,34(2):185-191
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Yanli Lei Karen Stumm Nils Volkenborn Stephen A. Wickham Ulrike-G. Berninger 《Marine Biology》2010,157(6):1271-1282
The benthic microbial food web can be responsible for a large proportion of benthic carbon cycling yet there are few data
on the trophic interactions between this food web and macrobenthos. A large-scale field experiment was conducted to investigate
effects of eliminating the polychaete Arenicola marina on benthic microbes (prokaryotes, heterotrophic and autotrophic protists) and metazoan meiofauna in a marine intertidal flat
of the North Sea, Germany. Over a period of 2 years, quantity and composition of micro- and meiobenthos from unmanipulated
sites were compared to those from sites deplete of lugworms. These grazer treatments were cross-classified with different
sediment characteristics (low- and mid-intertidal areas). Lugworm removal resulted in an initial increase in abundance of
prokaryotes and nanoflagellates, which became less pronounced in the second year. Ciliates were not affected quantitatively,
but in the absence of lugworms, diversity and the proportion of carnivorous forms increased. Meiobenthos (nematodes, ostracods
and copepods) were affected only moderately. The observed changes are probably due to a combination of release from grazing/predation
pressure, changes in the species composition of higher trophic levels (namely large polychaetes) and altered environmental
conditions (such as depth of the oxygenated layer and sediment grain size). Spatial differences between sites of different
tidal exposure/grain size appeared to be as large as temporal differences during the 2 years following the manipulation of
the system. We conclude that in intertidal sediments, indirect effects due to habitat transformation are as important as direct
biological interactions (grazing pressure and competition) for the dynamics of the benthic microbial food web. 相似文献
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于瑞士Greifen湖不同复水深度的位置,采集了直径为12cm的四个沉积物孔心样品,测得~(137)Cs的垂直剖面具相似的分布类型.由垂直剖面中~(137)Cs的峰值作沉积物计年标志得知:沉积物积累速度变化范围为0.22—0.085g/cm~2·a,随采样点与入湖的M(?)nch河口距离增加而递减.界面层沉积作用速率变化范围为1.4—0.55cm/a.显示出入湖泥沙输入和复水深度的双重影响.实际资料和理论概算表明.湖中的大部分~(137)Cs来自M(?)nch河积水盆地并在湖中得到净化. 相似文献