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991.
992.
Environmental impact assessment of sediment dumping in the southern Baltic Sea using meiofaunal indicators 总被引:1,自引:1,他引:0
Peter Frenzel Corinna Borrmann Beate Lauenburg Bjrn Bohling Jan Bartholdy 《Journal of Marine Systems》2009,75(3-4):430-440
An experimental sediment dumping was carried out in the southern part of the Mecklenburg Bight in June 2001. Foraminiferans and ostracods from superficial sandy sediment were studied in a time series from before dumping until March 2004 in order to assess changes in associations and recolonization patterns of both groups. Additionally, an area sampling covering the dumping site and its surroundings from 15.5 to 20.7 m water depth made it possible to compare associations inside and outside the dumping area as well as the water depth dependent distribution of foraminiferans and ostracods. Salinity values vary within the high alpha-mesohaline and low polyhaline range. The dominating species are Ammotium cassis (Foraminifera) and Sarsicytheridea bradii (Ostracoda). The diversity is low (Fisher alpha index from 0.4 to 3.2 for foraminiferans and 1.0 to 2.5 for ostracods), but higher within the dumping site samples. These higher values are explainable by input of allochthonous tests and valves representing additional species. After the sediment dumping it took two and a half years to re-establish the total foraminiferan association and the total foraminifer/ostracod ratio within the dumping site. Total foraminiferan abundance increases remarkably with water depth (mean 83 tests in 100 ml) driven by higher nutrient availability and more suitable salinity and temperature values within the zone of the oscillating halocline. The distribution of shallow water species such as Cribroelphidium excavatum, Eucythere argus and Hirschmannia viridis, within the transient water layer A. cassis, Nodulina dentaliniformis, S. bradii and Palmoconcha laevata and below Eggerella scabra indicate the depth position of the halocline. Water depth and sediment dumping influence are the main driving factors for the distribution of foraminifer and ostracod associations within the study area. However, a significant sedimentological difference between samples inside and outside the dumping area is not recognizable. 相似文献
993.
994.
Kho Shahriar Iqbal Gabriele Bulian Kazuhiko Hasegawa Md. Mashud Karim Zobair Ibn Awal 《Journal of Marine Science and Technology》2008,13(3):282-290
On the basis of previous studies, a series of hazards involving the typical small inland passenger ferries operating in inland
Bangladeshi waters have been identified. In particular, stormy weather conditions, overloading, and the risk of crowding to
one side have been determined as the typical events that are likely to lead to capsizing in the intact condition. In this
article, possible hazard mitigation measures are discussed, both from the regulatory and from the design point of view, for
a small inland ferry that is very similar to one that actually capsized in the past. The addressed design options involve
ballasting and hull modification by means of additional buoyancy above the waterline. From a regulatory point of view, it
is proposed that the present weather criterion in force in Bangladesh be modified by increasing the wind speed to be accounted
for and by considering the concurrent effects of wind, rolling, and the crowding of people to one side. 相似文献
995.
996.
汤秀英 《重庆交通大学学报(自然科学版)》2000,19(3):88-93
为了探讨处治挖方路基过湿土经济适用的方法 ,对其分别进行了换填、石灰处治、塑料网格加筋等室内外试验 ,得出了处治前后过湿土物理力学指标的变化情况 .结果表明 ,采用上述三种处治方法 ,尤其是换填和塑料网格加筋 ,能获得较好的效果 . 相似文献
997.
铝型树脂混合床制取脱盐水的实验研究 总被引:3,自引:1,他引:2
研究了铝型阳离子交换树脂与强碱性阴树脂混合床制取脱盐水的工艺方法及其再生过程,通过树脂改性提高再生废液的持续利用价值。从而消除对受纳水体的污染,并且降低系统的投入产出比。 相似文献
998.
通过大量调查研究和数据分析,阐述了长江流域国际集装箱多式联运以及EDI系统的发展现状,指出目前存在的问题,并提出若干建议。 相似文献
999.
航行于洲际间的远洋船舶,其压载水系统成为有害水生物入侵的主要途径之一。溶解在水中的氧是水域生命活动不可缺少的物质,但不同水生物对溶解氧的需求不同。实践证明:当溶解氧小于1 mg/L时,在1 h内,水生物将窒息而亡。论述以燃气作为惰性气体,置换远洋船舶压载系统中的空气,使水中的溶解氧小于1 mg/L,让入侵水生物窒息的方法,以保护本地水域生态平衡。结合我国油轮上配置的惰性气体系统(Inert Gases System,简称IGS),提出了方案设想和计算要点,与同行共同探讨。 相似文献
1000.
提出了水位加权系数平均值计算方法,利用水位站与测点的平面位置逐点进行水位改正,能有效提高水深测量的整体精度.新方法有利于计算机编程实现,免去了人工绘制联合潮位曲线,使感潮水域水深测量的整体精度和处理效率明显提高. 相似文献