Fast Ferry Traffic as a Qualitatively New Forcing Factor of Environmental Processes in Non-Tidal Sea Areas: A Case Study in Tallinn Bay,Baltic Sea

The impact of wake wash from high-speed ferries on the coastal environment in non-tidal seas is analysed in terms of wave energy and power, and properties of the largest waves. Shown is that hydrodynamic loads caused by heavy high-speed traffic may play a decisive role not only in low-energy coasts but also in certain areas with high wind wave activity. For example, ship-generated waves form, at least, about 5–8% from the total wave energy and about 18–35% from the wave power in the coastal areas of Tallinn Bay exposed to dominating winds. The periods of wake waves from high-speed ships frequently are much larger than dominating periods of wind waves. The leading waves typically have a height of about 1 m and a period of 10–15 s. Such waves extremely seldom occur in natural conditions in many regions of semi-enclosed seas. They cause unusually high hydrodynamic loads in the deeper part of the nearshore. The fast ferry traffic thus is a qualitatively new forcing component of vital impact on the local ecosystem. It is demonstrated that wakes from high-speed ferries may trigger considerable changes of the existing balance of coastal processes. Owing to their low decay rates combined with their exceptional compactness after crossing many kilometres of the sea surface, such wakes may cause considerable remote impact of the ship traffic. This feature has to be addressed in the analysis of the impact of harbours and associated ship traffic in the neighbourhood of vulnerable areas.     

Are the Curative Properties of ‘Black Mud’ from the Dead Sea Due to the Presence of Bitumen (Asphalt) or Other Types of Organic Matter?

Deep black clayey sediments of the Dead Sea, previously covered with water at times of higher sea level, are being mined for therapeutic purposes and for the preparation of cosmetic products under the name Black Mud. It was claimed that the beneficial properties are due to the presence of bitumen (asphalt) as attested by the colour. Less commonly, the curative properties have been ascribed to humic acids or to organic matter derived from algae in the lake. Asphalt from the Dead Sea has been of major economic importance to the region and was used as a medication for 2000 years until the mid-20th century. Geochemical analysis of the Black Mud showed that it contains relatively little organic matter (ca. 0.6–0.8% organic carbon) and that the organic matter is mostly derived from the land masses surrounding the lake. Asphalt was totally absent and the concentration of humic acids very low. The black colour of the mud is rather due to the poorly crystallised iron sulphides. Based on this, the therapeutic properties of the mud are ascribed to its content of reduced sulphur species, its physical and chemical properties and possibly its brine content, but not to the presence of organic matter.     

南黄海春季海水化学要素的分布特征

本文根据１９９６年４月“中韩黄海水循环及物质通量合作研究”项目的调查资料,首次对整个南黄海海域春季海水化学要素的分布特征进行了分析和探讨。结果表明,春季南黄海南部溶解氧含量及分布订受外海暖流水所控制,而中北部则主要受生物及生化活动的影响。     

北黄海与渤海沉积物中磷形态的分布特征

对1998年9月和1999年5月渤海航次和1999年8月北黄海航次所采集的柱状沉积物和表层沉积物样品进行了P形态的六步连续提取分析，分析了各种形态P在表层及垂直方向上的分布特征。并通过对沉积物充空气和N2条件下培养前后各步形态P的测定，认识各步形态P培养前后的变化以及不同的氧化还原环境对各步形态P的影响。结果表明：从渤海到并黄海总P的含量逐步降低。碎屑磷灰石的含量在六步中含量最高，约占50%左右，其次是非活性有机磷，约占20%，其他几步含量较小；充N2培养沉积物样品中碎屑磷灰石的含量要比充空气的低，其他形态的P较充空气培养的略高或相关不大。     

南海北部海域经济水产品的重金属污染及其评价

调查研究了南海北部海域鱼类、是类、蟹类、头足类和双壳类等５大类经济水产品中的Ｃｕ、Ｐｂ、Ｚｎ、Ｃｄ、Ｃｒ和Ｎｉ。研究结果表明，各类生物的重金属含量差异显著，重金属在鱼虾不同器官组织中的分布是不均衡的。鱼类的重金属含量与其栖息水层有关；除肉食性鱼类的Ｃｄ含量较高小，不同食性鱼类重金属含量间的差异不显著；近海鱼类的重金属含量与河口咸淡水鱼类的重金属含量之间无显著差异；鱼类重金属含量的季节变化不明显。游     

大气中CO2增加引起全球变暖和海平面上升及其对珠江三角洲可能的影响

本文是根据国内外大量实测数据，说明全世界大气层中二氧化碳不断增多，出现“温室效应”，使全球变暖，近地而大气层气温变化的情况；从而引起海面水温变化，使海洋上冰块瓦和融化，引起海平面上升。按世界各国学者研究的结果，近百年全球近地面大气层气温变化总的趋势是上升，北半球比较明显。海平面孔 有上升的趋势。按近40年中海平面可能上升0.4～1m的预测值，估计了海平面可能对珠江水位、沿海风暴潮潮位及咸潮入侵的影响，进而分析了对珠江三角洲、特别广州可能产生的危害。作者认为全球变暖和海平面上升当前还是一个不确定性问题，宜加强科学研究和实测。     

Salt enrichment of municipal sewage: New prevention approaches in Israel

Wastewater irrigation is an environmentally sound wastewater disposal practice, but sewage is more saline than the supplied fresh water and the salts are recycled together with the water. Salts have negative environmental effects on crops, soils, and groundwater. There are no inexpensive ways to remove the salts once they enter sewage, and the prevention of sewage salt enrichment is the most immediately available solution. The body of initiatives presently structured by the Ministry of the Environment of Israel are herein described, with the aim to contribute to the search for a long-term solution of salinity problems in arid countries. The new initiatives are based on: (1) search for new technologies to reduce salt consumption and discharge into sewage; (2) different technologies to cope with different situations; (3) raising the awareness of the public and industry on the environmental implications of salinity pollution; and (4) an elastic legal approach expressed through new state-of-the-art regulations. The main contributor to the salinity of sewage in Israel is the watersoftening process followed by the meat koshering process. Some of the adopted technical solutions are: the discharge of the brine into the sea, the substitution of sodium by potassium salts in the ion-exchangers, the construction of centralized systems for the supply of soft water in industrial areas, the precipitation of Ca and Mg in the effluents from ion-exchangers and recycling of the NaCI solution, a reduction of the discharge of salts by the meat koshering process, and new membrane technology for salt recovery.     

渤海湾西岸海平面上升威胁的防治对策

因受全球海平面上升和地面沉降的双重影响,在21世纪末渤海湾西岸海平面将相对上升90～260厘米,广大地区(包括天津市区)将处于大潮平均高潮位之下,自然岸线位置将后撤至津浦线附近.我们提出筑堤防潮引黄放淤提高建筑高程三位一体的治理方案。     

A method for prediction of extent of microbial pollution of seawater and carrying capacity of beaches

The increase in the number of tourists visiting a coast is desired by most of the countries for economic reasons. However, this increase in tourism may cause pollution of the sea. This can be only avoided by proper planning and by predicting the carrying capacity of the coast in terms of sea pollution. This is especially important for developing countries where part of the wastewater is discharged without any treatment into the sea.In the present study the beaches were classified according to their use — and consequently the amount of waste discharged into the sea — into four groups: (1) coasts that are used only for swimming and recreational purposes; (2) coasts used simultaneously for dwelling, swimming, and recreational purposes; (3) coasts along which only dwellings exist; and (4) natural and man-made harbors, i.e., coasts used as shelters. During the survey,40,320 observations were made between December 1985 and February 1988 to determine the effect of the number of tourists on seawater quality. The results obtained were analyzed by a multilinear regression program to obtain an empirical equation giving the extent of the sea pollution in terms of coliform concentration as a function of population density and some other environmental factors.The equations derived in this study enable the determination of the carrying capacity of a beach in terms of pollution as well as the expected degree of pollution corresponding to a given population density. Furthermore, it allows the prediction of the extra carrying capacity that can be obtained by improving the waste-disposal conditions.     

Use of remote sensing for the characterization of the Mediterranean coastal environment—the case ofPosidonia oceanica

The beds ofPosidonia oceanica, a marine vascular plant species endemic to the Mediterranean, form a major Mediterranean marine ecosystem. These beds are well-developed along the sandy east coast of Corsica, where the continental shelf is wide and extends for ca. 100 km. The upper limit of this ecosystem has been mapped by means of a computer image processing technique using 1/20 000 colour photographs. One of the major problems for image processing in the marine environment is the impact of the water layer (of variable thickness and quality), which can result in variations of the spectral signature for a particular vegetation or bottom type. In an attempt to reduce the impact of this artefact, a processing technique that takes into account bathymetric factors has been tested. Cartographical data obtained for an area extending from Bastia to Solenzara are presented. In the vicinity of the mouths of coastal rivers, a systematic indentation of the upper limit of the seagrass beds has been revealed. On the basis of these results, local variations in the quality of the marine environment can be detected, in particular with regard to salinity, turbidity and/or the impact of sedimentation. The overall surface area of thePosidonia oceanica beds has also been calculated.