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41.
European brackish water seas (Baltic Sea, Black Sea and Sea of Azov, Caspian Sea) are subject to intense invasion of non-indigenous species (NIS). In these seas, salinity is the most important range limiting factor and native species seem to reach a minimum species richness at intermediate salinities. This trend, revealed by Remane in 1934 and later on confirmed by many other scientists, was compared to the salinity range of already established NIS in the European brackish water seas. It turned out that most NIS are well adapted to the salinities holding lowest native species richness, already in their native area, and that NIS richness maximum in brackish water seas occurs in the salinity intervals of native species richness minimum. A predictable pattern in the salinity range of NIS can be used as a tool in initial risk assessment of future invasions in brackish water seas, especially when mapping highly potential donor and recipient areas. A product of empty niches, suitable environmental conditions, and availability of proper vectors might be the most effective predictor for the invasibility of brackish water areas.  相似文献   
42.
Qualitative and quantitative composition of meiobenthos was studied in Amursky Bay (Peter the Great Bay, the East Sea). Ten taxonomic groups were found, where nematodes were dominant. Density of meiobenthos in ground sediments of the Bay were not uniform, and the average density was measured at 126.4±62.3 ind. m-2. 56 species of nematodes were detected, and dominant species wereSabatieria palmaris, Paracanthonchus macrodon, Sphaerolaimus limosus, S. gracilis andOncholaimium ramosum. Five taxocenes of nematodes were allocated based on the results of cluster analysis and species domination according to density. Low diversity in species composition of nematodes was noted in the northwestern part of the Bay, which is a zone of desalination, and in the eastern part, which is exposed to household drains.  相似文献   
43.
王彦海  杨文川 《台湾海峡》2001,20(2):200-204
本文报道厦门海域软骨鱼灰星鲨(Mustelus griseus)感染的四叶目瘤槽科绦虫新种——厦门平槽绦虫Platybothrium xiamenensis sp.nov.,对新种形态特征进行了详细描述并与近似种作了比较.  相似文献   
44.
45.
1.Lecithochiriumfukenensissp.nov.(Fig.1)(Basedon6wholemounts)ThisspiceswascollectedinthestomachofTrichiurushaumelafromXiamenandNan'ao.Bodydividedintosomaandecsoma.Soma1,31~3.48×0.426~1.05(2.69×0.737),ecsoma0.22~0.80(0.448)longwhenprotruded,usuallycomple…  相似文献   
46.
匙指虾除少数为大型个体外,多数均为体长仅20-30mm的小型淡水虾类。在中国已报道有7属100多种。在检查多年来从全国各地收集的匙指虾标本中,发现有三个新种,现报道如下。  相似文献   
47.
Three new species of fossil dragonflies assigned to Sinokaratawia Nel,Huang and Lin in family Campterophlebildae,i.e.S,daohugouica sp.nov.,S.magica sp.nov.and S.gloriosa sp.nov.,and new materials of male S.prokopi Nel,Huang and Lin,2007 are described from the Middle Jurassic of Daohugou,Inner Mongolia,China.An emended diagnosis of genus Sinokaratawia was proposed.  相似文献   
48.
中国湿地生态系统的外来入侵种研究   总被引:10,自引:2,他引:10  
湿地是地球上各种生命形式高度聚集的生态体系之一,被称为“物种基因库”。湿地良好的环境条件不仅有利于本地种的生存,也利于外来物种的入侵。据现有资料统计,目前中国湿地生态系统中有外来入侵植物10种,隶属7个科;外来入侵动物53种,涉及哺乳类、鸟类、爬行类、两栖类、甲壳类、软体动物、鱼类和昆虫类。论述了这些入侵种的主要入侵途径,包括作为饲料、观赏、净化水质等目的人为有意引种,以及由非人为因素引起的入侵;同时还讨论了这些外来入侵种给湿地生态系统造成的不良影响,即导致物种多样性丧失、降低社会经济价值、破坏原有的生态系统和景观。  相似文献   
49.
On 26th December 2004, the world witnessed the devastating power of tsunami, affecting many countries, bordering the Indian Ocean region. This has caused significant changes in the shallow and intertidal regions of the Indian coast, especially the Andaman and Nicobar Islands, Tamil Nadu, Kerala and Pondicherry. The baseline data on biomass availability and distribution of benthic intertidal seaweed species were collected immediately after this catastrophic event by spot surveying 11 selected localities of the above-mentioned regions. In all, 45 species belonging to 31 genera were recorded during the present survey, the maximum number of seaweed species were recorded at Thirumullavarum, Kerala with the minimum at Car Nicobar, Andaman and Nicobar Islands. A very different trend was observed in the case of biomass availability at some locations which was due to the influence of habitat suitability over the tsunami damage. The details of this study have been provided in the present communication  相似文献   
50.
沿海表层沉积物中重金属的有效结合态   总被引:13,自引:0,他引:13       下载免费PDF全文
以浙江沿海表层沉积物为研究对象,系统地研究了重金属有效结合态与沉积环境、矿物组成和人为排放等环境因素之间的相互关系.结果表明:沿海表层沉积物中重金属的积累数量,呈现出潮汐河口沉积物>沿海沉积物>强潮汐河口沉积物的趋势,这反映了不同沉积类型对重金属富集作用的差异;重金属的有效结合态,总体上以铁锰氧化物结合态>碳酸盐结合态>硫化物及有机结合态>可交换态的顺序存在,但是不同的重金属或同种重金属在不同的采点,主要有效结合态的比例存在明显的差异,这不仅与重金属的地球化学性质、沉积环境和沉积物中的粘土矿物组成有关,更受到重金属污染物的人为排放量的影响.  相似文献   
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