Effects of point-source nutrient addition and mussel removal on epibiotic assemblages in Perumytilus purpuratus beds   总被引：2，自引：0，他引：2  

Nelson Valdivia  Martin Thiel   《Journal of Sea Research》2006,56(4):271-283

The objective of this study was to evaluate the effects of point-source nutrient addition and mussel removal on species diversity of the epibenthic assemblage of the purple mussel Perumytilus purpuratus. It was hypothesised that mussels cushion the effects of disturbance on the associated organisms and thereby favour species diversity in patches with added nutrients. In order to test this hypothesis, a two-factorial field experiment was conducted at an exposed rocky shore of northern-central Chile in which nutrient addition and mussel removal were manipulated with two levels. Experimental units consisted of 100-cm² mussel plots that were sampled after two months of experimental manipulations. Local nutrient addition was done with coated slow-release fertilisers. Mussel removal treatments consisted in three destructive events applied throughout the experimental phase, and each event consisted in the removal of 20% of the mussel biomass from each plot. While point-source nutrient addition had only minor effects on diversity, mussel removal had significant and negative effects on faunal species richness and the abundance of suspension-feeders and sessile organisms. The abundance of predators/scavengers significantly decreased with mussel removal in the presence of nutrient addition. Grazers and mobile organisms were very abundant in the mussel assemblage but their abundance remained unaffected by treatments. Finally, species richness and total abundance of algae were also not affected by the treatments. Although the duration of our experiment was relatively short, we suggest that the effects of local nutrient addition are of minor importance at the study site in comparison to the effects of mussel removal. Based on our results and previous studies conducted in soft-bottom systems, we suggest that physical and biological stress acting on exposed hard-bottom communities overshadows the potential effects of local nutrient addition.  相似文献   

Environmental features and crustacean community of anchihaline hypogean waters on the Kornati islands, Croatia     

Sanja Gottstein  Marija Ivkovi&#;  Ivan&#;ica Ternjej  Branko Jal&#;i&#;  & Mladen Kerovec 《Marine Ecology》2007,28(S1):24-30

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Balancing exploitation and conservation of the eastern Scotian Shelf ecosystem: application of a 4D ecosystem exploitation index     

Bundy  Alida; Fanning  Paul; Zwanenburg  Kees C.T. 《ICES Journal of Marine Science》2005,62(3):503-510

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中国绿球藻目的新种和新变种   总被引：2，自引：0，他引：2  

毕列爵  梁良弼  凌元洁  胡征宇 《海洋与湖沼》1996,27(4):347-356

饶钦止和沈国华等人于１９５０、１９５２、１９５５和１９９０年自湖北、江苏、广西和黑龙江等地采得标本，经鉴定表明，它们为中国绿球藻目，分隶于６属的８个新种和４个新变种，模式标本保存于中国科学院水生生物研究所藻类标本室。  相似文献   

Distribution and species composition of mass occurrences of large-sized sponges in the northeast Atlantic     

A.B. Klitgaard  O.S. Tendal 《Progress in Oceanography》2004,61(1):57-98

The geographic and bathymetric distribution of “ostur”, that is mass occurrences of large-sized astrophorid demosponges, first recognized at the Faroe Islands during the internordic BIOFAR programme (Marine Benthic Fauna of the Faroe Islands), are mapped for the northeast Atlantic. This is done on the basis of information obtained during the sampling of the BIOICE programme (Benthic Invertebrates in Icelandic Waters) as well as during cruises at Karmoy (southwest Norway), the Trondheim Fjord (middle Norway), the Koster area (southwest Sweden) and the Denmark Strait (southeast Greenland). In addition, information has been acquired from Nordic and German biologists and fishermen regarding the occurrence of “ostur”. These data together with the sparse information in the literature show that the geographic distribution of the “ostur” areas follows two band-shaped arcs, defined by the Norwegian Atlantic Current and the Irminger Current. The local occurrence of “ostur” is, however, to a great extent dependent on areas of variable topography where a hard bottom is present.The results show that two main types of “ostur” can be recognized in the northeast Atlantic. Firstly a boreal “ostur” which is dominated by Geodia barretti, Geodia macandrewi, Geodia atlantica, Isops phlegraei, Stryphnus ponderosus and Stelletta normani, and occurs around the Faroe Islands, Norway, Sweden, parts of the western Barents Sea and south of Iceland. Secondly a cold water “ostur” characterized by the same genera but represented by different species, viz. Geodia mesotriaena, Isops phlegraei pyriformis and Stelletta rhaphidiophora, which is found north of Iceland, in most of the Denmark Strait, off East Greenland and north of Spitzbergen. A number of hexactinellid species are also represented in the cold water “ostur”, the most frequently occurring being Schaudinnia rosea.Suggestions are given regarding the possible causes for observed changes in the distribution of “ostur” as well as to the biological importance of these areas.  相似文献   

The Effects of Industrial Pollution on the Development and Succession of Marine Fouling Communities I. Analysis of Species Richness and Frequency Data     

P. J. Moran  T. R. Grant 《Marine Ecology》1989,10(3):231-246

Abstract. The effects of industrial pollution were determined by comparing the pattern of development of marine fouling communities situated along a pollution gradient within Port Kembla Harbour (Australia) with those from nearby Wollongong Harbour, a relatively unpolluted area. Fifty-three fouling species were found in the communities from Wollongong Harbour compared to only 40 in those from Port Kembla Harbour. Twenty-eight species (including many bryozoans) occurred only in the former, while 15 species occurred solely in the latter. Ten of the 25 species common to both areas were more numerous in Port Kembla Harbour, probably because of the greater availability of free substratum and food in this area. The species richness of fouling communities in Port Kembla Harbour was found to decrease as pollutant concentrations increased. In both study areas, communities established in summer showed significantly higher species richness than those whose development was initiated in winter. This difference was less pronounced in Port Kembla Harbour and was attributed to the effects of pollution on larval settlement. Although species richness increased at all sites through time, Wollongong Harbour communities contained a greater number of species at the end of the experiment than communities from Port Kembla Harbour. Despite this, fewer species were found in the very early developmental stages of the communities from Wollongong Harbour. This result highlights the inherent problems associated with using species richness or diversity measures as a means of determining marine environmental quality.  相似文献   

厦门及其邻近地区虾池浮游动物的组成及分布   总被引：4，自引：0，他引：4  

林元烧  曹文清  方旅平  杨圣云 《海洋科学》2002,26(5):8-12

分析了1999年8月至2000年7月逐月采自厦门及其附近地区（厦门杏林、龙海角美、漳浦前亭）4个虾池的浮游动物样品345份、鉴定出浮游动物36种（类），本文初步报道浮游动物的种类组成，浮游动物的种类数和浮游动物的总个体数量的季节分布，并对不同地区的虾池浮游动物的若干生态特征做了比较。  相似文献   

Desert grassland canopy arthropod species richness: temporal patterns and effects of intense, short-duration livestock grazing     

G.S. Forbes  J.W. Van Zee  W. Smith  W.G. Whitford   《Journal of Arid Environments》2005,60(4):627-646

Arthropods living in the canopies of two woody shrub species (a sub-shrub (Gutierrezia sarothrae) and a large shrub (Prosopis glandulosa)) and perennial grasses plus associated herbaceous species, were sampled on 18, 0.5 hectare plots in a Chihuahuan Desert grassland for five consecutive years. Mesquite shrubs were removed from nine plots, six plots were grazed by yearling cattle in August and six plots were grazed in February for the last 3 years of the 5 year study. Arthropod species richness ranged between 154 and 353 on grasses, from 120 to 266 on G. sarothrae, and from 69 to 116 on P. glandulosa. There was a significant relationship between the number of families of insects on grass and G. sarothrae and growing season rainfall but species richness was not a function of growing season rainfall on any of the plants. Several of the arthropod families that were the most species rich in this grassland were found on all of the plants sampled, i.e. Salticid spiders, Bruchid and Curculionid beetles, Cicadellid and Psyllid homopterans, and ants (Formicidae). There were more species rich families that were shared by grasses and the sub-shrub G. sarothrae than with mesquite. The absence of a relationship between growing season rainfall and species richness was attributed to variation in life history characteristics of arthropods and to the non-linear responses of annual and perennial desert grassland plants to rainfall.There were no significant differences in insect family or species richness on any of the plant types as a result of removal of mesquite (P. glandulosa) from selected plots. Intense, short duration (24 h) grazing by livestock during in late summer resulted in reduced species richness in the grass-herb vegetation layer but had no effect on insect species richness on snakeweed or mesquite shrubs. Livestock grazing in winter had no effect on insect species richness on any of the vegetation sampled.  相似文献   

开滦范各庄煤矿地质特征及F0断层富水性   总被引：2，自引：0，他引：2  

张春立 《中国煤田地质》2002,14(4):21-22

断层发育特征及其富水性的确定,多少年来人们主要靠地面钻探及井下揭露获得信息,继而提出矿井防治水措施。笔者根据采区三维地震成果,并结合瞬变电磁法成果,对贯穿开滦矿务局范各庄煤矿南一、南二、南三、南四四个采区的F0断层进行了研究。主要对该断层的发育特征及其富水性进行了探讨与评价,其成果可为拟定煤矿防治水方案提供较全面可靠的设计依据。  相似文献   

土壤盐分特征对内陆盐沼盐生植物群落的影响          下载免费PDF全文

崔乔  何彤慧  全晓塞  陈向全  何玉实 《盐湖研究》2021,29(1)

为研究内陆盐沼植物群落的分布对土壤盐分的响应特征,选取鄂尔多斯盐湖盐沼区作为研究区,筛选了肉质耐盐植物群落,苔草植物群落和禾草植物群落3类典型植物群落,开展了土壤含水量、pH、电导率以及Na_⁺,K_⁺,Mg2_⁺,Ca_{^{2 +}},Cl_^-、SO_4^2-、CO_3^2-和HCO_3^-的测定,分析了区内典型植物群落对土壤水盐因子的响应规律。探讨了3类植物群落之间土壤因子含量的差异性;采用相关性分析和CCA分析,评价了3类植物群落多样性及物种分布随土壤因子的变化规律。结果表明,区内3类植物群落中,土壤盐分含量表现为肉质耐盐植物群落最高,苔草植物群落最低,禾草植物群落居中;植物多样性与土壤中含量最高的Na_⁺和SO_4^2-的相关性最显著;植物分布同时受到土壤盐分、水分和pH的显著影响。研究结果可为鄂尔多斯盐湖区土壤盐渍化改良和植被恢复提供理论支撑。  相似文献