象山港,三门湾潮间带生态学研究：Ⅱ.数量组成与分布     

邵晓明  范明生 《海洋学研究》1996,14(4):35-41

象山港、三门湾软相潮间带底栖动物数量的水平分布与港湾的屏蔽性程度有一定的关系，生物量是三门湾（１８０．９５ｇ／ｍ２）高于象山港（９４．４７ｇ／ｍ２），生物密度是象山港（８１６个／ｍ２）高于三门湾（３４７个／ｍ２）。决定所面生物数量变化的主要底栖动物种类数随着港湾屏蔽性程度的提高而相应地减少。生物数量的垂直分布主要受潮汐作用的影响，以中潮区为最高。生物量以６月份最大，密度是４月份最大。  相似文献   

洞庭湖轮虫生态分布的研究   总被引：5，自引：0，他引：5  

邵国生 《海洋湖沼通报》1992,(4):41-49

1985～1986年,对洞庭湖水体进行了8次轮虫样品的采集和分析。两年观察到轮虫108种,其中终年出现的种类有10种。轮虫总数O—512.8ind./L,全湖平均75.1ind./L。本文从湖区自然生态环境对轮虫种类、数量的影响进行研究,探讨了大型开放湖泊轮虫分布与若干生态因子的关系。认为泥沙含量、流速、营养盐多寡以及入湖水体轮虫种群状况是影响洞庭湖轮虫分布的主要因素。  相似文献   

舟山潮间带生态学研究：Ⅱ.数量及其分布   总被引：3，自引：0，他引：3  

蔡如星  郑锋 《海洋学研究》1991,9(3):58-72

舟山潮间带生物种类数量的平面分布与盐度和海岸开敞性有关,垂直分布与潮汐有关;群落数量的水平分布与底质和海岸开敞性有关,垂直分布与潮汐有关。舟山潮间带生物有明显的分带现象,隐蔽的岩岸区分为:滨螺带和藤壶-牡蛎带两个带;开敞性岩岸区分为:滨螺带,藤壶-(虫戚)-藻类带及藻类带3个带。沙滩区分为:沙蟹带和浅蛤-斧蛤带两个带;泥沙滩区分为:盐碱植物-滨螺带和招潮蟹-大眼蟹带;泥滩区分为:蟹守螺-囊螺带和蟹守螺-织纹螺带。  相似文献   

Holocene cheniers in the Yangtze Delta, China   总被引：1，自引：0，他引：1  

Qinshang Yan  Shiyuan Xu  Xusheng Shao 《Marine Geology》1989,90(4):337-343

Nineteen cheniers formed in the middle and late Holocene have been distinguished and studied.

In fair weather the wave action along the Yangtze Delta is weak, with a wave height of 0.5–1.0 m and average wave energy of 0.127 erg/s. However, in late summer and early autumn the coastal area is usually swept by typhoons, which sometimes are extremely violent. The development of cheniers is mainly controlled by these strong typhoons. As a result, a number of the sedimentary characteristics of the cheniers are related to the typhoon-generated high-energy environment.

Moreover, the study shows that the top elevation of a fully developed chenier indicates the spring high water level during a violent typhoon (11–12 on the Beaufort scale).  相似文献   

用铀系定年法测定南永1井珊瑚礁年龄     

刘韶  张惠玲  秦佩玲  温孝胜 《热带海洋学报》1993,(3)

运用铀系定年法首次对南水1井珊瑚礁岩心中的两个层位进行测年,结果与~(14)C测年一致,证实在晚更新世与全新世之间存在沉积间断面。  相似文献   

大窑湾海域水化要素分布及相关关系的探讨     

邵秘华  孙茜  贺广凯  张国光  刘彤 《海洋科学进展》1995,(2)

本文依据大窑湾的环境调查资料为基础，系统地阐述了水体中化学要素ｐＨ、盐度、透明度、ＤＯ、ＣＯＤ、ＴＯＣ、浊度、悬浮物、ＮＨ４－Ｎ、ＮＯ２－Ｎ、ＮＯ３－Ｎ、ＰＯ４－Ｐ、ＳｉＯ３－Ｓｉ、Ｃｕ、Ｐｂ、Ｚｎ、Ｃｄ、Ａｓ、Ｈｇ、Ｃｒ、硫化物、六六六、石油等分布规律。诸要素主要是在潮流水动力支配下，形成扩散带。各要素中仅有无机氮和ＰＯ４－Ｐ两项含量超标，其余要素含量范围都是处于海水正常浓度水平，属于一类海水水质。文章并对各要素进行相关关系分析。  相似文献   

Molecular identification of bloom-forming species Phaeocystis globosa (Pryninesiophyta) and its dispersal based on rDNA ITS sequence analysis     

Chen Yueqin  Shao Peng  Wang Ning  Zhou Hui  Qu Lianghu  Linda K. Medlin 《海洋学报(英文版)》2003,22(2):243-253

The colony-forming Phaeocystis species are causative agents of dense bloom occurrences in coastal waters worldwide. It is difficult to separate them because of the different morphologies associated with their colonial stages. In this study we applied molecular approaches to analyze the genetic variation of Phaeocystis globosa and Phaeocystis pouchetii from several geographic regions, and to assist in tracing the dispersal of bloom-forming Phaeocystis species in coastal waters of China. The sequences of the internal transcribed spacers (ITS1 and ITS2) of rDNA and the 5.8S ribosomal RNA gene of Phaeocystis strains were determined. Sequence comparison shows that P.globosa was the most divergent to P. pouchetii, exhibiting sequence divergence higher than 0.08. However, lower genetic divergences existed between strains of P.globosa. The sequence comparison of the Phaeocystis rDNA ITS clearly shows that the species isolated from the southeast coast of China is identified as P.globosa rather than P. cf. pouchetii or other species. Furthermore, the significance of rDNA variation in distinct global populations of P.globosa suggested it might have had sufficient time to accumulate detectable mutations at the rDNA locus, supporting the hypothesis of ancient dispersal of P.globosa to many areas, meaning that P.globosa blooms in the coastal waters of China are endemic rather than a newly introduced species or a foreign source. Finally, based on the high divergent region of rDNA ITS, a pair of species-specific primers for P.globosa were designed, they could be useful to detect the presence of this species in mixed plankton assemblages or flagellate stages that are recognized with diffculties by means of conventional microscopy.  相似文献   

Comparison of single- and dual-permeability models in simulating the unsaturated hydro-mechanical behavior in a rainfall-triggered landslide     

Wei Shao  Zongji Yang  Junjun Ni  Ye Su  Wen Nie  Xieyao Ma 《Landslides》2018,15(12):2449-2464

Landslide-prone slopes in earthquake-affected areas commonly feature heterogeneity and high permeability due to the presence of cracks and fissures that were caused by ground shaking. Landslide reactivation in heterogeneous slope may be affected by preferential flow that was commonly occurred under heavy rainfall. Current hydro-mechanical models that are based on a single-permeability model consider soil as a homogeneous continuum, which, however, cannot explicitly represent the hydraulic properties of heterogeneous soil. The present study adopted a dual-permeability model, using two Darcy-Richards equations to simulate the infiltration processes in both matrix and preferential flow domains. The hydrological results were integrated with an infinite slope stability approach, attempting to investigate the hydro-mechanical behavior. A coarse-textured unstable slope in an earthquake-affected area was chosen for conducting artificial rainfall experiment, and in the experiment slope, failure was triggered several times under heavy rainfall. The simulated hydro-mechanical results of both single- and dual-permeability model were compared with the measurements, including soil moisture content, pore water pressure, and slope stability conditions. Under high-intensity rainfall, the measured soil moisture and pore water pressure at 1-m depth showed faster hydrological response than its simulations, which can be regarded as a typical evidence of preferential flow. We found the dual-permeability model substantially improved the quantification of hydro-mechanical processes. Such improvement could assist in obtaining more reliable landslide-triggering predication. In the light of the implementation of a dual-permeability model for slope stability analysis, a more flexible and robust early warning system for shallow landslides hazard in coarse-textured slopes could be provided.  相似文献   

Up-to-date urban rainstorm intensity formulas considering spatial diversity in China     

Danna Shao  Guang-sheng Liu 《Environmental Earth Sciences》2018,77(14):541

With accelerating urbanization in China, urban waterlogging has had a serious impact on urban sustainable development and citizen welfare. Simple urban rainstorm intensity formulas with a monotonous frequency distribution type cannot meet the practical needs of urban drainage planning and design. This study focuses on the development of urban rainstorm intensity formulas based on spatial diversity in China. Using the annual maximum sampling method, rainstorm data of 607 cities throughout China were collected into a database, with a total of 24,933 rainfall samples (annual observations) under various specified precipitation durations. The database was used to verify that integrating the Pearson III and Gumbel distributions would constitute an optimal theoretical distribution type, owing to its small error and increased fitting precision. Modification and coordination of four important parameters in the rainstorm intensity formula were done using a digital elevation model, which improved the accuracy of the formula. In addition, precipitation distributions in China were treated from the perspective of topographic features to validate the calculations from up-to-date formulas. Accuracy assessment was accomplished using a national code (GB-50014-2006), GIS-based isograms, and authoritative results from the Hydrological Bureau of the Ministry of Water Resources. This work provides a comprehensive foundation for the establishment of an up-to-date rainstorm intensity formula for China, which can be used widely in different cities.  相似文献   

Characterization of the mechanical properties of a claystone by nano-indentation and homogenization     

Fan Zhang  Hanqun Guo  Dawei Hu  Jian-Fu Shao 《Acta Geotechnica》2018,13(6):1395-1404

Based on the analyses of mineralogical compositions by X-ray diffraction and microstructure by optical microscopy, the Young’ modulus and hardness of a claystone were characterized by the nano-indentation technique and homogenization method. Three distinct microstructural zones are identified in the claystone: clay matrix, a composite matrix of clay and small mineral grains and imbedded quartz grains. The elastic modulus and hardness of different zones were determined by nano-indentation testing. Based on the statistical analysis of nano-indentation results, the spatial mappings and frequency distributions of elastic modulus and hardness of the different zones were obtained. The elastic moduli of main constituent phases of the claystone are then estimated from the nano-indentation tests. These values were further used for the determination of the macroscopic elastic modulus of the claystone using two different homogenization schemes: the dilute scheme and Mori–Tanaka scheme. The predicted values by the homogenization schemes are compared with experimental data obtained from conventional uniaxial compression tests.  相似文献