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171.
Mountain Water Tower and Ecological Risk Estimation of the Mesta-Nestos Transboundary River Basin (Bulgaria-Greece) 总被引:1,自引:1,他引:1
K. Grunewald J. Scheithauer J.-M. Monger N. Nikolova 《山地科学学报》2007,4(3):209-220
The Mesta-Nestos river basin in Bulgaria and Greece is a case study for transboundary decision-making support in south-eastern Europe and a show-case for the development of methodologies and information-gathering for the integrated regional planning of water resources. Land-use conflicts in this water-scarce region cover a wide spectrum of activities like agricultural irrigation,drinking water production,diversions for industrial water,and risk of pollution from mining,to name a few examples. Measurements of the water quality were carried out in the upper basin. Results will be illustrated by the example of the environmental situation in the alpine region of the Pirin National Park as well as in the Razlog Basin with a stronger anthropogenic impact and pollution around a former uranium mine near the village of Ele?nica. The social and economic development of this transboundary region is a recently established priority for the future. It will mean an increase in water usage and more stress for the water resources if regional impacts of global climate change are verified. Problem-focused management of the catchment area as a whole on the basis of proved geo-data sets is needed for the future. 相似文献
172.
Theconcentrationanddistributionofdimethylsulfideinthemarineatmosphericboundarylayerneartheequator¥LiXingsheng;LiZhe;F.Parungo... 相似文献
173.
Decades of commercial planting and other anthropogenic processes are posing a threat to the riparian landscapes of the Cauvery river basin, which supports a high floral diversity. Despite this, the habitats in the upstream sections of the River Cauvery are still intact, as they are located in sacred groves. To understand the dynamism of riparian forests exposed to anthropogenic pressures, the upstream stretch of Cauvery extending from Kushalanagara to Talacauvery (~102 km) was categorized into two landscapes: agro ecosystem and sacred (i.e. preserved). The tree species were sampled using belt transects at 5 km intervals and the regeneration status of endemic species assessed using quadrats. A total of 128 species belonging to 47 families, and representing 1,590 individuals, was observed. Amongst them, 65% of unique species were exclusive to sacred landscapes. A rarefaction plot confirmed higher species richness for the sacred compared to the agro ecosystem landscapes, and diversity indices with more evenness in distribution were evident in sacred landscapes. A significant loss of endemic tree species in the agro ecosystem landscapes was found. Overall, this study demonstrates that an intense biotic pressure in terms of plantations and other anthropogenic activities have altered the species composition of the riparian zone in non-sacred areas. A permanent policy implication is required for the conservation of riparian buffers to avoid further ecosystem degradation and loss of biodiversity. 相似文献
174.
The physical stresses associated with emersion have long been considered major factors determining the vertical zonation of intertidal seaweeds.We examined Porphyra umbilicalis(Linnaeus) Kützing thalli from the vertical extremes in elevation of an intertidal population(i.e.upper and lower intertidal zones) to determine whether Porphyra thalli acclimate to different vertical elevations on the shore with different patterns of nitrate uptake and nitrate reductase(NR) and glutamine synthetase(GS) activities in response to different degrees of emersion stress.We found that the nitrate uptake and NR recovery in the emersed tissues took longer in lower intertidal sub-population than in upper intertidal sub-population;and GS activity was also significantly affected by emersion and,interestingly,such an activity was enhanced by emersion of thalli from both upper and lower intertidal zones.These results suggested that intra-population variability in post-emersion recovery of physiological functions such as nutrient uptake and NR activity enables local adaptation and contributes to the wide vertical distribution of P.umbilicalis.The high GS activity during periodic emersion stress may be a protective mechanism enabling P.umbilicalis to assimilate nitrogen quickly when it again becomes available,and may also be an evidence of photorespiration during emersion. 相似文献
176.
回顾了自1995年6月在SanJorge盆地引进核磁共振测井以来的应用情况。至今,Atlas公司采用Numar珠磁共振成像测井仪,斯伦贝谢公司采用组合磁性共振测井仪共进行了400次测井,共对2000多个层位进行了射孔和生产测试。 相似文献
177.
本文根据灰色系统中的聚类原理,提出了有关复测网区内地壳活动区的灰色划分方法,即根据动态平差得到的观测值速率和关联度这两个灰类指标,对观测值按不同的灰类进行灰色聚类,从而划分地壳的相对活动区。文中给出了重力网重复观测值的灰色关联度、聚类权以及灰类白化函数的计算方法,并用一个复测重力网资料进行了计算,结果表明:用该方法所划出的相对活动区与实际情况比较符合。 相似文献
178.
C. K. Tseng 《中国海洋湖沼学报》1983,(3)
In the course of our studies on some old collections of marine cyanophytes in the herbarium of the Institute of Oceanology, we came across a very interesting plant characterized by (1) a crescent-shaped filament attached to the substrate with its middle portion while the two side portions growing freely and bending upwards, (2) its reproduction being carried out by heterocysts and homorgones. Careful studies showed that it is an undescribed species 相似文献
179.
在古地磁和岩石磁学研究中,海陆第四纪沉积物磁性是一个独具魅力的研究领域。它不仅为研究地磁场的时、空特性提供关键数据,而且为几百万年来的地质演化提供重要信息。例如,第四纪沉积物记录了发生于大约0.73MaB.P.布容/松山极性时地磁转换时地磁场的特性。目前,从南、北两半球获得的古地磁转换数据可以用来验证地磁场的倒转 相似文献
180.
We recalculate the diffuse flux of high-energy neutrinos produced by gamma-ray bursts in the relativistic fireball model. Although we confirm that the average single burst produces only approximately 10-2 high-energy neutrino events in a detector with a 1 km2 effective area, i.e., about 10 events yr-1, we show that the observed rate is dominated by burst-to-burst fluctuations that are very large. We find event rates that are expected to be larger by 1 order of magnitude, likely more, which are dominated by a few very bright bursts. This greatly simplifies their detection. 相似文献