青海湖区的生态环境研究

本文依据青海湖区的自然地理条件,湖水特征,湖水位下降,探讨了青海湖区的治理措施。     

基于熵权的未确知测度模型在湖库富营养化评价中的应用

利用基于熵权的未确知测度模型对8个湖库的富营养化状况进行了评价.为了有效解决权重计算困难的问题,根据各指标值的差异程度,利用熵权确定了各指标的权重.评价对比结果表明,基于熵权的未确知测度模型客观地考虑了指标权重问题且原理简单、思路清晰,利用该模型可以对湖库富营养化进行合理评价,但要注意置信度的选取范围.     

High precision topographic data on Lop Nor basin＇s Lake ＂Great Ear＂ and the timing of its becoming a dry salt lake

High precision elevation measurements using DGPS were carried out along three representative tran-sects for the ＂Great Ear＂ area, a dry salt lake within the Lop Nor basin. Results indicate that the Lop Nor basin is only 5.2 m deep and its lowest point occurs at the center of the ＂Great Ear＂. In addition, the basin is asymmetric-steeper in the southwest （0.19‰） and gentler in the northeast （0.09‰）. Points along the same ＂Great Ear＂ ring were found to have an identical elevation value, but different when from different ones （lower towards the center）. The spacing of the ＂Great Ear＂ rings was found to be closely related with the surface steepness. The closer the ＂Great Ear＂ rings are spaced, the steeper the ground surface, and vice versa. These findings support the argument that the ＂Great Ear＂ rings are the former shoreline trails left behind by Lop Nor water during the last few episodes of recession towards its total dry up. A comprehensive analysis of the high precision elevation data, historical accounts, aerial and satellite photographs and imagery, and official topographic maps of the study area suggests that the ＂Great Ear＂ area in the Lop Nor basin was incorrectly mapped as being covered by a great body of water on the 1963 topographic maps. A re-interpretation of the 1958 aerial photographs and newer remote sensing imagery indicated that the ＂Great Ear＂ ring structure was already in place in 1958 and it continued to appear on the subsequent remote sensing data without any major changes. It is estimated that lake water in the ＂Great Ear＂ area of the Lop Nor basin disappeared between the late 1930s and early 1940s.     

The reconstruction and interpretations of lake status at 6 ka and 18 ka B.P.in inland mainland Asia

By means of survey of literature through compilations of sedimentological, biogeological and geomorphologic data, the inland lake level changes in arid or semi-arid mainland Asia at 6 and 18 ka B. P. have been reconstructed. The results showed that the lakes from western and northwestern Asia were characterized by very high water levels at 18 ka B. P., but low or intermediate water stands at 6 ka B. P. The high lake level in this region was associated with the southward displacement of westerlies, therefore, the extent of the high lake stand indicated the southern flank of westerlies during the glaciation. Conversely, the lakes from the eastern and southern Asia registered comparative low levels at 18 ka B. P. and significantly high one at 6 ka B. P. The lowering of lake level at 18 ka B. P. was caused by the weakened summer monsoon and the high lake level at 6 ka B. P. by the enhanced summer monsoon induced by the enlarged thermal contrast between land and ocean. The extent of high lake levels indicated the northern boundary of monsoon expansion. Between the above two regions, there is a climatic transitional zone in the Central Asia where the lake behavior was close to that in southeastern Asia at 6 ka B. P. but became similar to that in northwestern Asia at 18 ka B. P. Thus this zone became a transitional sector from the monsoon to the westerlies.     

白头鹤在升金湖越冬习性初步观察

安徽升金湖是白头鹤 ( Grusm onacha)主要越冬地之一 ,每年越冬数量 30 0— 40 0只 ,最高年份可达 46 2只 ( 1994年 )。每年 10月下旬至 11月初迁抵越冬 ,翌年 4月初北迁 ,越冬期14 5天左右。白头鹤越冬期以家族或由家族组成群体 ,休息、觅食、抚幼等活动     

河流湖泊水体生物-生态修复技术述评

从脱氮除磷及去除藻类两方面介绍了国内外生物-生态修复技术,分析了水体生物-生态修复技术的优缺点．分析表明：与磷资源回收利用相结合的脱氮除磷技术,具有工程造价低、耗能少、处理效果好且能实现资源回收利用等特点;超声波除藻技术及生物除藻技术,能有效地去除藻类且不会产生二次污染．     

扁担塘两种底栖动物的周年生产量

研究了1996年4月至1997年3月间扁担塘两种底栖动物———幽蚊和圆扁螺的周年生产量,采用体长频率法测算的生产量分别是:幽蚊周年生产量湿质量为0.1419g·m-2·a-1,干质量为0.0114g·m-2·a-1,P/B系数为1.8;圆扁螺的周年生产量带壳湿质量为1.6266g·m-2·a-1,去壳干质量为0.0732g·m-2·a-1,P/B系数为7.1.但与国外数据相比,这些结果比较适中,说明扁担塘并不是幽蚊和圆扁螺的最适生长环境.     

洪湖的环境变迁及其生态对策

总结了洪湖的湖泊环境和生物资源在近几十年开发过程中所发生的改变,分析了目前洪湖所存在的水生物资源衰退、富营养化过程加速、养殖调蓄矛盾、过滤圈养和潜在污染威胁等主要生态问题,提出了合理规划、应用生态工程措施保护湖泊生物资源、综合治理洪湖的生态对策措施。     

淮阳龙湖湿地水质现状及保护对策

通过对淮阳龙湖四个湖区湖水PH值、透明度、气味、颜色、总硬度、氯化物、OD、BOD等指标的测定,分析了淮阳龙湖湿地目前存在的问题及其原因。根据龙湖目前的自然环境和社会经济状况,针对性的提出了龙湖湿地的保护对策。