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781.
对全球气候变化原因及发展趋势之浅见 总被引:1,自引:0,他引:1
分析了引起全球气候变化的各种可能原因,对温室气体、植被破坏、水汽变化等对全球气候变化的影响作了概括总结,阐述了全球气候变化发展趋势及气候变化预测中应注意的问题。 相似文献
782.
Ecological effects of reactivation of artificially stabilized blowouts in coastal dunes 总被引:1,自引:0,他引:1
J. H. van Boxel P. D. Jungerius N. Kieffer N. Hampele 《Journal of Coastal Conservation》1997,3(1):57-62
In an inner dune area in the Dutch coastal dunes several artificially stabilized blowouts were reactivated. The purpose was
to investigate whether these reactivated blowouts could remain active despite the increased atmospheric deposition of nutrients,
how much area would be affected by sand from the blowouts, whether the vegetation would respond to the deposition of sand,
and whether the reactivation of blowouts could be a measure against the effects of acidification and eutrophication.
This paper presents the results of the first years of minitoring the changes in the blowout morphology and the response of
the vegetation. In the monitoring period (1991–1994) the blowouts remained active and grew slowly in size and depth. The area
which receives more than 1 cm of calcareous sand from the blowout in three years was up to six times the area of the blowouts.
Moss vegetation responded to the accumulation of sand:Campylopus introflexus was sparse within the deposition area whereasTortula ruralis was found near the contour of 1 cm deposition in 3 yr. No indications were found that shrubs or marram grass were adversely
affected by the deposition of sand.
The experiment forms part of a programme to test measures aimed at mitigating the effects of air pollution on natural landscapes.
From the viewpoint of the programme the experiment is a success. 相似文献
783.
It is expected that the Baltic region becomes a major centre of economic growth and prosperity in Europe already during this
decade (Anon. 2000). Therefore, an Agenda 21 for the Baltic region (Baltic 21) was developed to ensure a sustainable development.
Especially the coastal ecosystems are subject to increasing anthropogenic pressure e.g. eutrophication, traffic, harbours,
tourism or offshore wind parks. Eutrophication remains the main ecological problem in the Baltic Sea and has serious negative
social and economical consequences. Inner and outer coastal waters play an important role as buffers and filters for the Baltic
proper. Consequently, the utilization and preservation of their self-purification capacity is of great importance.
Combined results of our own coastal research and of the international workshop ‘Baltic coastal ecosystems: structure, function
and coastal zone management’ (Rostock University, November 2001) are presented here. Conclusions for an improved integrated
coastal zone management of Baltic coastal ecosystems will be presented. 相似文献
784.
A. Sirois C.L. Blanchard D.M. Whelpdale H.M. Michaels 《Atmospheric environment (Oxford, England : 1994)》1996,30(24):4115-4124
The capability of deposition networks in eastern Canada to resolve regional trends has been examined by Blanchard et al. (1996, Atmospheric Environment 30, 2539–2549). This paper extends the earlier methods to permit evaluation of the need for specific individual sites, comparison of additional network configurations, and consideration of more regions. Parameter estimates for the statistical model are improved by using monthly instead of annual data. For the regions that we examined, eliminating all provincial sites in eastern Canada would cause an increase of 1 to 6 years in the time required for reaching a 90% probabiility of detecting the expected future trends. The elimination of certain key provincial sites may increase the uncertainties in the determination of deposition isopleths of particular interest, such as the 20 kg ha−1 yr−1 contours. The statistical techniques presented here are quite general and can be extended to statistical tests or estimators other than those illustrated here. 相似文献
785.
786.
787.
788.
从城考结果看城市污水处理的发展趋势 总被引:5,自引:0,他引:5
分析了我国十年来重点城市污水处理的发展和现状 ,以及污水处理存在的问题 ,对“十五”期间城市环境综合整治定量考核中城市生活污水处理率和城市生活污水的处理水平提出新的要求 相似文献
789.
790.
Environmental impact of two successive chemical treatments in a small shallow eutrophied lake: Part II. Case of copper sulfate 总被引:3,自引:0,他引:3
Van Hullebusch E Deluchat V Chazal PM Baudu M 《Environmental pollution (Barking, Essex : 1987)》2002,120(3):22-634
The appearance of cyanobacteria ( > 10 colony per ml) was not prevented after alum treatment. In order to prevent cyanobacteria efflorescences in a small shallow polymictic lake (Courtille, France), copper sulfate was applied. Treatment level was 63 microg 1(-1) as Cu2+ from CUSO4, 5 H2O. Cyanobacteria were kept under control during the summer. Microcystis sp. completely disappeared, which allowed swimming in the lake throughout the tourist season. Microcystis only reappeared 2 months after the treatment. Copper content in the water column only returned to its background level 2 months after copper addition. This high residence time of copper in the water might have been caused by complexation and adsorption of copper on natural organic matter, whose level was high in the ecosystem studied. A mechanism of transfer of 'truly' dissolved copper towards particulate copper has been underlined and explains the disappearance of this fraction of copper in the water column. 相似文献