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立足样品测试数据,利用空间分析、空间插值、地质统计以及景观生态学方法,深入分析了深圳大鹏湾表层沉积物碎屑矿物的空间分布特征,并使用球状模型对相应半变异函数进行理论建模。结果表明,碎屑矿物分布的Hurst分维数为0.28~0.97,空间几何分维数为1.03~1.72;Moran Ⅰ型空间自相关系数-0.15~0.53。在此基础上,以等值线分布所包围范围作为划分尺度,以Shannon-Wiener信息指数作为度量,得到的矿物分布所反映出的信息量或者富集程度指数为0.88~1.85。 相似文献
94.
Molecular identification of bloom-forming species Phaeocystis globosa(Prymnesiophyta)and its dispersal based on rDNA ITS sequence analysis 总被引:3,自引:1,他引:3
Abstract-The colony-forming Phaeocystis species are causative agents of dense bloom occurrences incoastal waters worldwide. It is difficult to separate them because of the different morphologies associatedwith their colonial stages. In this study we applied molecular approaches to analyze the genetic variationof Phaeocystis globosa and Phaeocystis pouchetii from several geogrtaphic regions, and to assist in tracingthe dispersal of bloom-forming Phaeocystis species in coastal waters of China. The Sequences of the inter-nal transcribed sacers (ITS1 and ITS2) of rDNA and the 5.8S ribosomal RNA gene of Phaeocystisstrains were determined. Sequence comparison shows that P.globosa was the most divergent toP. pouchetii, exhibiting sequence divergence higher than 0.08. However, lower genetic divergences ex-isted between strains of P.globosa. The sequence comparison of the Phaeocystis rDNA ITS clearlyshows that the species isolated from the southeast coast of China is identified as P. globosa rather thanP. cf. po 相似文献
95.
Abstract. We describe the basic ecology of two key-hole limpets, Fissurella crassa and Fissurella limbata , which are heavily harvested by coastal shellfishermen (mariscadores) at the rocky intertidal of central Chile. The ecological role of human predation on these species was assessed. Anthropic exclusion from a stretch of the rocky intertidal at Las Cruces (non-harvested area) for about two and a half years resulted in changes of the densities and size distributions of these fissurelid species as compared to populations in control zones (harvested area). Differential human predation generates, on key-hole limpets, responses of different intensities related to the accessibility of man to the mesohabitats (sheltered platforms, exposed platforms and vertical walls) and fringes of the intertidal (mid-low intertidal and Lessonia nigrescens fringe). Thus, size distributions and mean densities of both fissurelids differ widely between the harvested and non-harvested areas on both platform habitats but not on vertical walls. In the mid-low intertidal fringe, differences are greater than in the less accessible L. nigrescens intertidal fringe. Moreover, we discuss the way in which other species, directly harvested by mariscadores (i. e., the mollusc Concholepas concholepas) can affect the keyhole limpet populations of central Chile rocky shores. Finally, we highlight the ecological role of these limpets on the dynamics of intertidal ecosystems and how they can modify community landscape. 相似文献
96.
Sequence variation of the first internal transcribed spacer of ribosomal DNA ( ITS - 1 ) was examined and its application to the study of genetic variation was explored in four populations of farter' s scallop Chlamys farreri. ITS - 1 fragments, with a length of about 300 bp,of 78 individuals collected from Dalian, Qingdao, Yantai in China and Korea respectively were amplified via PCR, cloned and sequenced. Intra-genomic variation was examined by sequencing several clones of single individuals. Alignment and polymorphism analysis detected 44 haplotypes and 50 polymorphic sites which consist of 30 substitutions and 20 indels, indicating a high level of polymorphisms. Sequence analysis also showed a very low level of intra-individual variation. All these features validated the feasibility of application of ITS - 1 fragment to population analysis. Polymorphism analysis showed that the Korea sample has the richest genetic variation, followed by Yantai and Qingdao samples. AMOVA (analysis of molecular variance) showed that the majority (96.26%) of genetic variation was distributed within populations and 3.74% resulted from among populations, but with P 〈 0.05 ( = 0.042), indicating that the populations in this study have significant divergence. This output was basically concordant with the result arising from RAPD data and different from that from mitochondrial 16S rDNA sequence data. Discussion on this inconsistency was made accordingly. 相似文献
97.
98.
Abstract. Biokarst-forms on limestone coasts are developed and arranged according to the bionomic zonation. The development of biokarst is the result of bioerosion, a synergistic effect of biological corrosion by endoliths and biological abrasion by grazers.
The cumulative effect of biogenic carbonate destruction leads to coastal destruction with a resulting highly profiled morphology on the limestone surfaces along the coastal profile. Under the influence of environmental factors a zonation of organisms develops which brings in turn a zonation of erosion rates (0.1-1.1 mm a-1 ) resulting in biokarst-forms such as rock holes, rock pools and notches.
Products of bioerosion on limestone coasts are dissolved carbonate (by biological corrosion, 10–30% of the decomposed limestone) and particulate carbonate (by biological abrasion, 70–90% of the decomposed limestone) both of which contribute directly or indirectly to nearshore sedimentation. Size and shape of the bioerosional grains are determined by the boring pattern of the endoliths. The fine-grained sediments (maximum within the fraction 20–63 μm) contribute 3–25 % to the nearshore sediments.
Drastic changes in the biological zonation (like the mass invasion of the sea urchin Paracentrotus lividus in the Northern Adriatic since 1972 which eliminated nearly the entire macrophyte zone) due to unknown factors or pollution can have a profound effect on the bioerosion rates, altering them by as much as a factor of ten. 相似文献
The cumulative effect of biogenic carbonate destruction leads to coastal destruction with a resulting highly profiled morphology on the limestone surfaces along the coastal profile. Under the influence of environmental factors a zonation of organisms develops which brings in turn a zonation of erosion rates (0.1-1.1 mm a
Products of bioerosion on limestone coasts are dissolved carbonate (by biological corrosion, 10–30% of the decomposed limestone) and particulate carbonate (by biological abrasion, 70–90% of the decomposed limestone) both of which contribute directly or indirectly to nearshore sedimentation. Size and shape of the bioerosional grains are determined by the boring pattern of the endoliths. The fine-grained sediments (maximum within the fraction 20–63 μm) contribute 3–25 % to the nearshore sediments.
Drastic changes in the biological zonation (like the mass invasion of the sea urchin Paracentrotus lividus in the Northern Adriatic since 1972 which eliminated nearly the entire macrophyte zone) due to unknown factors or pollution can have a profound effect on the bioerosion rates, altering them by as much as a factor of ten. 相似文献
99.
The Role of Isopod Crustaceans in the Reef Crest Community at Carrie Bow Cay, Belize 总被引:1,自引:0,他引:1
Abstract. The species composition and numbers of specimens of isopod crustaceans from the rubble of a Belizean reef crest were obtained. Four sets of 30 samples were taken from three rubble zones (rubble with algal turf, rubble between Thalassia plants, and pure rubble), in four different collecting periods. Twenty-four species of isopods were identified, sexed and counted. By means of a Likelihood Ratio Chi-square Contingency Table Analysis the presence of 13 species was shown to be positively correlated with habitat, 15 species with season, and nine species with habitat and season combined. From the spread of total numbers and of ovigerous females it is proposed that the isopods may be grouped into three patterns: a) those present and breeding in the reef crest rubble throughout the year, i. e. stress-tolerant species; b) those showing a breeding peak in summer and a population decrease in winter-spring, i. e. opportunist species; and c) those showing a breeding peak in the fall, and a second peak in spring, and a decrease or complete avoidance of the habitat, especially by ovigerous females, in the summer. The diversity of the Belizean reef crest isopod fauna is compared with the published report of the isopod fauna of a coral reef in Madagascar. Several similarities in composition are noted. The multiplicity of microhabitats is invoked as a possible explanation for the relatively high diversity of anthuridean isopods in coral reefs. 相似文献
100.
九龙江口红树林上附着动物的生态 总被引:12,自引:2,他引:12
福建九龙江口红树林附着动物7种,白脊藤壶Balanus albicostatus和白条地藤壶Euraphia withersi在数量上占绝对优势,是危害红树的主要附着动物。附着动物在河口红树林区的数量分布随着盐度的降低而减少,其栖息密度和生物量的高峰期在夏,秋两季。生长茂密的红树林(郁蔽度大于0.5),附着动物主要分布于水流畅通的向海边缘和潮沟边缘的红树上。水流畅通程度是影响附着动物在红树林区向纵 相似文献