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291.
Gerhard Rheinheimer 《Die Naturwissenschaften》1998,85(7):318-329
3 , NOx, PO4) caused eutrophication and consequent oxygen depletion in coastal bottom waters as well as in the depths of the open sea.
In the anoxic sediments, hydrogen sulfide can be produced by protein-decomposing and sulfate-reducing bacteria. The bottom
fauna will be destroyed and only H2S tolerant microorganisms can survive.
Originating from cellulose manufacturing and from paper mills, large amounts of poisonous chlorinated compounds contaminated
the coastal waters of Sweden and Finland until the 1980s. Most of this material is still present in sediments of the central
Baltic Sea and can be resuspended by near bottom currents.
To reduce pollution and improve the situation in the Baltic Sea, the surrounding countries organized the Helsinki Convention,
which came into force on 3.5.1980. The Helsinki Commission (HELCOM) founded in 1974 acts as coordinator and is responsible
for the enforcement of the Baltic monitoring program and international research projects. The activities of HELCOM have led
to the reduction of dangerous pollutants which in turn has caused the regeneration of flora and fauna in some areas. Further
improvements can be expected. 相似文献
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Norbert Winker Gerhard Stehlik Helmut Tausch Wolfgang Nyiry 《Environmental Sciences Europe》1994,6(5):247-250
An interlaboratory test was organized by the Allgemeine Unfallversicherungsanstalt, Dept. HUB (Department for the Prevention of Occupational Accidents and Diseases) for the analysis of polycyclic aromatic hydrocarbons (PAH). The aim of the test was to compare analytical results of serveral laboratories performing PAH analysis as routine work. In a preliminary study four different PAH-containing solutions were analyzed by independent laboratories in Germany and Austria. The concentrations of 17 PAH (according to the relevant NIOSH-methods) were to be determined. The results reveal the problems involved in the analysis of PAH. 相似文献
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The parthenogenetic Marmorkrebs (marbled crayfish) produces genetically uniform offspring 总被引:1,自引:0,他引:1
Genetically identical animals are very much in demand as laboratory objects because they allow conclusions about environmental
and epigenetic effects on development, structures, and behavior. Furthermore, questions about the relative fitness of various
genotypes can be addressed. However, genetically identical animals are relatively rare, in particular, organisms that combine
a high reproduction rate and a complex organization. Based on its exclusively parthenogenetic reproduction mode, it has been
suggested that the Marmorkrebs (Crustacea, Decapoda, Astacida), a recently discovered crayfish, is an excellent candidate
for research addressing the aforementioned questions. However, until now, a study using molecular markers that clearly proves
the genetic uniformity of the offspring has been lacking. Here, with this first molecular study, we show that this crayfish
indeed produces genetically uniform clones. We tested this with 19 related individuals of various generations of a Marmorkrebs
population by means of six different microsatellite markers. We found that all examined specimens were identical in their
allelic composition. Furthermore, half of the analyzed loci were heterozygous. These results and the absence of meioses in
previous histological studies of the ovaries lead us to conclude the Marmorkrebs propagates apomictically. Thus, a genetically
uniform organism with complex morphology, development, and behavior is now available for various laboratory studies. 相似文献
300.
Maren Olbrich Marion Wenig Karl-Heinz Häberle Rainer Matyssek Michael Leuchner Katja Schlink Gerhard Welzl Dieter Ernst Günther Bahnweg 《Environmental pollution (Barking, Essex : 1987)》2010,158(4):1043-1050
In 2006, a controlled infection study was performed in the ‘Kranzberger Forst’ to address the following questions: (1) Will massive artificial inoculation with Apiognomonia errabunda override the previously observed inhibitory effect of chronic ozone? (2) Can biochemical or molecular markers be detected to account for the action of ozone? To this end six adult beech trees were chosen, three ozone fumigated (2× ozone) and three control trees (ambient = 1× ozone). Spore-sprayed branches of sun and shade crown positions of each of the trees, and uninoculated control branches, were enclosed in 100-L plastic bags for one night to facilitate infection initiation. Samples were taken within a five-week period after inoculation. A. errabunda infestation levels quantified by real-time PCR increased in leaves that were not fumigated with additional ozone. Cell wall components and ACC (ethylene precursor 1-amino cyclopropane-1-carboxylic acid) increased upon ozone fumigation and may in part lead to the repression of fungal infection. 相似文献