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21.
Relationships Between Community Structure of the Intertidal Macroinfauna and Sandy Beach Characteristics Along the Chilean Coast 总被引:2,自引:0,他引:2
Eduardo Jaramillo Heraldo Contreras Cristian Duarte & Pedro Quijón 《Marine Ecology》2001,22(4):323-342
Abstract. Eight sandy beaches were seasonally sampled along the coast of Chile, from ca. 21 to 42° S (about 3000 km) to study the relationship between community structure of the intertidal macroinfauna and beach characteristics. Sediment samples (0.1 m2 , 30 cm deep) were collected (July – September 1998 and December 1998 – January 1999) with plastic cylinders at 15 equally spaced levels along three replicated transects extending from above the drift line to the swash zone. The sediment was sieved through a 1 mm mesh and the organisms collected stored in 5 % formalin. To define beach types, Dean's parameter (Ω) was calculated from wave heights and periods, and fall velocity of sand particles from the swash zone. Crustaceans (mainly peracarids) were the most diverse group with 14 species, followed by polychaetes with 5 species. The talitrid amphipod Orchestoidea tuberculata , the cirolanid isopods Excirolana braziliensis and E. hirsuticauda and the anomuran decapod Emerita analoga were the most widely distributed and common species. Regression analyses between species richness, abundance and biomass of the whole macroinfauna versus sediment characteristics, beach face slopes and morphodynamic beach states showed no significant relationships. Thus, macroinfaunal community characteristics did not increase linearly from lower intermediate to higher intermediate or dissipative beach states as had been found before in Chile or in other coasts. A comparative analysis with data from sandy beaches of other world regions showed that the number of species inhabiting Chilean sandy beaches was generally lower, whereas total population abundances were generally higher compared with values reported elsewhere. 相似文献
22.
砂质海岸岸滩侵蚀演变模式探讨——以山东南部海岸侵蚀岸段的岸滩演变为例 总被引:5,自引:0,他引:5
在分析山东南部海岸几十年来的地形观测资料的基础上,运用砂质海岸等深线变化预测理论,建立该区的岸滩侵蚀演变预测模型,研究了该区域岸滩演变规律。实测资料验证表明:预测结果合理,基本反映了本区岸滩演变的特征。 相似文献
23.
中华绒螯蟹人工半咸水工厂化育苗试验研究报告 总被引:1,自引:0,他引:1
在盐度为14—19‰的人工海水中,温度20—25℃条件下,189只平均体重100g的抱卵亲蟹产蚤状幼体4025万只。布苗密度为50—100万只/m~3为宜。必须经常换水,保持水质良好。人工饵料以单胞藻和丰年虫无节幼体为主,可适当加喂蛋黄。 相似文献
24.
Susanne Qvarfordt Hans Kautsky Torleif Malm 《Estuarine, Coastal and Shelf Science》2006,67(4):618-628
The pillars of the bridge connecting the Island of Öland with the Swedish mainland were rebuilt between 1990 and 2000. The renovation produced pristine vertical concrete substrates, which became submerged in known years and seasons. The fouling communities on the pillars were examined in 2001 to determine whether the community structure could be explained in terms of either orderly successional development or of seasonal variation in the settlement of benthic organisms. As well, the communities on the pillars were compared to communities on the vertical surfaces of boulders in the area. The results indicated that an annual species composition is the final stage in the succession on the observed, vertical constructions. The few perennial species add to the variation between pillars as they increase in biomass (Polysiphonia fucoides) or become out-competed (Balanus improvisus). Also, observed seasonal differences in the biomass of these perennial species indicated that the time of year free space becomes available might be an important determinant of the future structure of the community. Comparison between the pillar and boulder communities showed that the artificial structures were not surrogates for the natural hard substrate: pillar communities differed in that they lacked most perennial algal species and had a high biomass of B. improvisus. 相似文献
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28.
桩式离岸堤保滩促淤工程消浪效果试验研究 总被引:9,自引:0,他引:9
在上海奉贤南北港保滩促淤工程中,采用了一种新型结构型式-桩式离岸堤,并通过物理模式试验进行了桩式离岸堤消浪效果研究。针对离岸堤通常建于近岸水区破波带的特点,重点研究水深,堤高以及堤身结构对波浪衰减的影响,同时对桩式离岸堤堤后水域的波浪底流速 分析探讨。研究结果表明,桩式离岸堤不仅具有良好的消浪效果。而且可在较大范围内改变波态,即由引起水体剧烈紊动的破波转变为浅水推进波,从而有效地改善海滩上的动力条件,促进海滩免受侵蚀,是一种具有广泛应用前景和新型保滩促淤结构。 相似文献
29.
A novel method for prediction of the load carrying capacity of a corroded reinforced concrete beam (CRCB) is presented in the paper. Nine reinforced concrete beams, which had been working in an aggressive environment for more than 10 years, were tested in the laboratory. Comprehensive tests, including flexural test, strength test for corroded concrete and rusty rebar, and pullout test for bond strength between concrete and rebar, were condueted. The flexural test results of CRCBs reveal that the distribution of surface cracks on the beams shows a fractal behavior. The relationship between the fractal dimensions and mechanical properties of CRCBs is then studied. A prediction model based on artificial neural network (ANN) is established by the use of the fractal dimension as the corrosion index, together with the basic intbrmation of the beam. The validity of the prediction model is demonstrated through the experimental data, and satisfactory resuits are achieved. 相似文献
30.
长竹蛏人工育苗技术的初步研究 总被引:4,自引:0,他引:4
本文对长竹蛏繁殖习性、胚胎发育和人工育苗技术关键进行研究.结果表明亲贝经暂养可促进性成熟;幼虫对温、盐度的适应较广;变态附着采用缩光培育,未经缩光的附着时间延长,存活率降低;幼虫长至约240μm变态附着,附着量在(0.6~10)×106个/m 相似文献