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1.
The Dead Sea of Israel, Jordan and Syria is a severely disturbed ecosystem, greatly damaged by anthropogenic intervention in its water balance. During the 20 th century, the Dead Sea level dropped by more than 25 meters, and presently (2003) it is at about 416 meters below mean sea level. This negative water balance is mainly due to the diversion of water from the catchment area of the lake by Israel, Jordan and Syria. During the 2002 World Summit on Sustainable Development Israel and Jordan jointly announced their interest in saving the Dead Sea by constructing the ‘Peace Conduit’ that will pipe water from the Red Sea to the Dead Sea. The inflow of seawater (or reject brine after desalinization) into the Dead Sea will have a major impact on its limnology, geochemistry and biology. During the filling stage, relatively diluted surface water will form and the rate of evaporation will therefore increase. Dilution of the surface water will most likely result in microbial blooming whose duration is not known, while the lower water layer is likely to develop reducing conditions, including bacterial sulfate reduction and presence of hydrogen sulfide (H2S). Mixing between the calcium-rich Dead Sea brine and the sulfate-rich seawater will result in gypsum precipitation (CaSO4·2H2O). Once the target level is reached, inflow will be outbalanced by evaporation and salinity of the surface water will increase due to accumulation of sea water-salts. The water column will remix when the density of the surface water will equal that of the lower water column. In spite of its large volume and high salinity relative to that of the inflowing water, over the long run the composition of this unique lake will change. Before a decision is made on the planning and construction of the Conduit, it is essential that the long term evolution and characteristics of the ‘renewed’ Dead Sea be known and anticipated changes examined. Once decided upon, the planning and construction of the Conduit should be conducted so as to minimize possible negative impacts of seawater introduction on the Dead Sea. This can only be achieved through a thorough understanding of the expected changes in the limnological physical/chemical characteristics of the Dead Sea and its unique brine.  相似文献   

2.
Introduction The alluvial fan along the eastern and southern m argins of the D ead Sea (hereafter denoted D S) consists of fine to coarse-grained siliclastic sand and pebble-size gravel w ith thin intercalations of lam inated m arl of H olocene age (Pow e…  相似文献   

3.
The demand for water resources in the area south of the Dead Sea due to continued development, especially at the Arab Potash Company (APC) for production and domestic purposes necessitates that water quality in the area be monitored and evaluated based on the local geology and hydrogeology. The objective of this paper is to monitor seasonal fluctuations of groundwater and to determine how fluctuation in the water levels will affect the groundwater quality. Groundwater levels were found to be influenced by rainfall and pumping of water from the wells for domestic and industrial use. Twenty water samples were collected from different wells and analyzed for major chemical constituents both in pre- and post-seasons to determine the quality variation. Chemical constituents are significantly increased after post-season recharge. According to the overall assessment of the area, water quality was found to be useful for drinking, irrigation and industry.  相似文献   

4.
Pollution monitoring of marine organisms grown in the Zhoushan Sea of China   总被引:5,自引:1,他引:5  
PolutionmonitoringofmarineorganismsgrownintheZhoushanSeaofChinaZhouQixing,ZhuYinmeiDepartmentofEnvironmentalSciences,Zhejiang...  相似文献   

5.
SeawaterintrusionincoastalareasofYellowSeaandBohaiSeaShengXuebin;SunJianzhong;DaiZhaohua(ResearchCenterforEco-EnvironmentalSe...  相似文献   

6.
7.
TheU .S .EnvironmentalProtectionAgencyrequestedtheNationalResearchCouncil(whichistheoperatingarmoftheU .S .NationalAcademyofSciencesandtheU .S .NationalAcademyofEngineering)tocarryoutacriticalscientificevaluationofindicatorstomonitorecologicalchangesfromeit…  相似文献   

8.
The peculiar biogeography of the so-called Lost World, i.e. the summits of sandstone tableaux (tepuis) in the Neotropical Guyana region of Venezuela, has generated a debate regarding the factors that are thought to account for modern vegetation patterns in the region. Some argue that plant communities on these high-elevation summits reflect a long history of evolution in isolation, while others surmise that there has been substantial biotic interchange with the surrounding lowlands during glacial times. Until now, these apparently competing hypotheses have not been tested using palaeoecological methods. I used pollen analysis of Quaternary sediments and documented past vertical migrations of vegetation in response to climate changes, which supports the second hypothesis. Physiographical analysis, however, shows that about half the tableaux summits are too high for their flora to have reached the lowlands during the last glaciation, suggesting that a portion of the tableaux vegetation has always experienced some degree of biotic isolation. Thus, a component of the summit vegetation evolved in isolation, whereas other taxa experienced interchange, as reflected in endemism patterns among the tableaux summits. Biogeographical patterns on the summits are the result of complex evolutionary processes. The two hypotheses invoked to explain the vegetation patterns are not mutually exclusive, but instead complement one another.  相似文献   

9.
-In order to reduce the increasingly serious environmental impact caused by wastewater from the paper industry, the municipality of Jinan plans to adopt a specialized production technology. The new technology will centralize pulp production and decentralize paper production. It is predicted that the new technology will greatly reduce the environmental effects of the paper industry. Perhaps it is a new direction for the development of the paper industry in China.  相似文献   

10.

Objective

To explore the views and practices of maternal-fetal medicine specialists on offering fetoscopic endoluminal tracheal occlusion (FETO) for left- and right-sided congenital diaphragmatic hernia (LCDH, RCDH) in the post Tracheal Occlusion To Accelerate Lung growth (TOTAL)-trial era.

Method

Cross-sectional knowledge, attitude and practice survey was conducted among 105 attendees of the 19th World Congress of Fetal Medicine.

Results

On average, respondents were knowledgeable about CDH, involved in research, and provided antenatal treatment options. Four out of five (82%) agreed that neonatal survival in LCDH can be reliably predicted in the prenatal period. Few respondents considered the exact risks and benefits of FETO for severe LCDH as being unclear (16%), yet half were uncertain about this for moderate LCDH (57%) and severe RCDH (45%). Most respondents offer FETO for severe LCDH (97%) and RCDH (79%), but only 59% offer it for moderate LCDH. However, half of respondents (58%) stated that not offering FETO for moderate LCDH would be a psychological burden for parents.

Conclusion

Respondents consider the risk-benefit ratio of FETO for severe LCDH clear and consistently offer FETO, but not for moderate LDCH and severe RCDH. However, not offering the option of FETO to parents was considered a psychological burden.  相似文献   

11.
DevelopmentoftheprocedureforthestabilizationofrainwatersamplesYuanZhongxin;Chung-ShinYuan(DepartmentofChemicalEngineeringNati...  相似文献   

12.
Purification function of the natural wetland in the Liaohe Delta   总被引:6,自引:0,他引:6  
1IntroductionStructure,functionandchangearethreeimportantaspectsoflandscapeecology(Forman,1986).Landscapefunctionmeanstheinte...  相似文献   

13.
14.
Today it is generally accepted that the Earth's magnetic field, as well as that of many other planets, is generated by buoyancy driven convection in the electrically conducting liquid cores of these rotating celestial bodies. The conversion of mechanical energy into electromagnetic energy is known as the dynamo effect. In contrast to technical dynamos, which utilize the rotational motion of a complex arrangement of wire coils and other materials of different electrical and magnetic properties, the geodynamo is based on a freely developing spiral flow in a practically homogeneous, electrically conducting liquid core domain, and is therefore termed a homogeneous dynamo. This report outlines some fundamental properties of the Earth's magnetic field. The structure of the spiral flow in the liquid interior of planets is explained with the help of some model experiments in rapidly rotating spherical shells, which were carried out by Busse and Carrigan (1974). Based on the main ideas of electromagnetism it is shown that spiral motion in well-conducting fluids, like liquid metals, can amplify seed magnetic fields to generate dynamo action. Starting from the conjectured flow structure in the Earth's interior, a conceptional and engineering design is described for a laboratory dynamo experiment. Some details of the construction of the test facility and first experimental results are presented and discussed.  相似文献   

15.
16.
On the study of ecosystem health:state of the art   总被引:2,自引:0,他引:2  
IntroductionDuringlastdecades,theterm“ecosystemhealth”isusedwithincreasingfrequencyintheliterature.Thegrowinginterestsinthestu...  相似文献   

17.
It is argued that there are at least five reasons for the Northeast states of the United States to implement a regional emission trading scheme for carbon dioxide despite the lack of federal policy regulations: goodwill, learning, political influence, risk management and competitiveness interests. Using an energy-economy model, the carbon price to bring the firms into compliance with a 10% reduction by 2020 is estimated to be 20-150 US$ per ton C. There have been discussions about linking the ongoing EU Emission Trading Schemes to the Northeast state initiative. The prime argument is that such a linkage would encourage a change of the federal US policy, which has traditionally followed action taken at the state level. Emissions trading with binding mitigation commitments could thus be demanded and accepted also on federal level. This paper demonstrates that the impact of linkage on permit prices depends on the reduction target in the European scheme: A low EU target results in a net flow of permits to the Northeast scheme, while a 40% EU reduction target results in a net flow of permits from the Northeast. Flow of permits from the Northeast state must be compensated for by the EU because the United States is not a party of the Kyoto Protocol. The EU must therefore buy permits in allowances recognized in the Kyoto regime in an amount equal to the net flow of permits from the Northeast states.
T. A. PerssonEmail:
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18.
Amethodforcalculatingthetotalozoneamountintheclearskies¥BaiJianhui;WangGengchen(InstituteofAtmosphericPhysics,ChineseAcademyo...  相似文献   

19.
20.
StudyonthewaterqualityoftheTaihuLakeusinggenotoxicologicalmethodsWuQinglong,ChenKainingNanjingInstituteofGeographyandLimnol...  相似文献   

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