The community structure of intertidal macrobenthos in Changdao Archipelago(north of Shandong Peninsula,between Bohai Bay and the northern Yellow Sea) was examined based on samples collected from 14 stations in five tr...The community structure of intertidal macrobenthos in Changdao Archipelago(north of Shandong Peninsula,between Bohai Bay and the northern Yellow Sea) was examined based on samples collected from 14 stations in five transects in June 2007.Three stations corresponding to high,medium and low tidal areas were set up for each transect.A total of 68 macrobenthic species were found in the research region,most of which belonged to Mollusca and Crustacea.The average abundance and biomass of the macrobenthos was 1 383 ind./m2 and 372.41 g/m2,respectively.The use of an arbitrary similarity level of 20% resulted in identification of five groups among the 14 stations in the research region.There were remarkable differences in the biomass,abundance and Shannon-Wiener diversity index of the different sediments.Specifically,the order of biomass was rocky shores > gravel > mud-sand > coarse sand > stiff mud,while the order of abundance was rocky shores > coarse sand > mud-sand > gravel > stiff mud,and that of the diversity index was mud-sand > gravel > stiff mud > rocky shores > coarse sand.The above results revealed that the sediment type was the most important factor affecting the structure of the macrobenthic community of the intertidal zone.展开更多
为查明蓬莱近海岸的地应力状态,开展了2个钻孔(深度小于200m)的水压致裂地应力测量工作,并与长岛附近海域3个钻孔的地应力状态进行了对比,采用回归分析方法,分析了该地区地应力随深度变化的特征,结合最大剪应力与平均主应力之比(μ m)...为查明蓬莱近海岸的地应力状态,开展了2个钻孔(深度小于200m)的水压致裂地应力测量工作,并与长岛附近海域3个钻孔的地应力状态进行了对比,采用回归分析方法,分析了该地区地应力随深度变化的特征,结合最大剪应力与平均主应力之比(μ m)和侧压力系数( K′)探讨了研究区的断层稳定性。结果表明:蓬莱近海岸和长岛海域的地应力状态基本一致,最大水平主应力方向主要表现为北东东至东西向,这与华北的区域应力场相一致;水平应力的梯度大于环渤海圈的平均地应力梯度;研究区浅部三向主应力相对大小以 S H >S h >S v 为主,这有利于逆断层的活动;研究区 K′值和μ m值均较高,分布区间分别为:2.76~3.98和0.47~0.59;陆区断层与区域应力方向均以较大角度相交,处于稳定的状态;海域的北西西向和北东向断层与区域应力场的方向夹角较小,如果区域应力持续增强,将有利于走滑断层的活动,这与震源机制以走滑型地震为主相符。研究结果对研究区内断层稳定性的评价和重大工程的设计及施工都具有重要参考意义。展开更多
基金Supported by Shandong 908 Project for Islands Investigationthe Knowledge Innovation Program of Chinese Academy of Sciences (No 072715)
文摘The community structure of intertidal macrobenthos in Changdao Archipelago(north of Shandong Peninsula,between Bohai Bay and the northern Yellow Sea) was examined based on samples collected from 14 stations in five transects in June 2007.Three stations corresponding to high,medium and low tidal areas were set up for each transect.A total of 68 macrobenthic species were found in the research region,most of which belonged to Mollusca and Crustacea.The average abundance and biomass of the macrobenthos was 1 383 ind./m2 and 372.41 g/m2,respectively.The use of an arbitrary similarity level of 20% resulted in identification of five groups among the 14 stations in the research region.There were remarkable differences in the biomass,abundance and Shannon-Wiener diversity index of the different sediments.Specifically,the order of biomass was rocky shores > gravel > mud-sand > coarse sand > stiff mud,while the order of abundance was rocky shores > coarse sand > mud-sand > gravel > stiff mud,and that of the diversity index was mud-sand > gravel > stiff mud > rocky shores > coarse sand.The above results revealed that the sediment type was the most important factor affecting the structure of the macrobenthic community of the intertidal zone.
文摘为查明蓬莱近海岸的地应力状态,开展了2个钻孔(深度小于200m)的水压致裂地应力测量工作,并与长岛附近海域3个钻孔的地应力状态进行了对比,采用回归分析方法,分析了该地区地应力随深度变化的特征,结合最大剪应力与平均主应力之比(μ m)和侧压力系数( K′)探讨了研究区的断层稳定性。结果表明:蓬莱近海岸和长岛海域的地应力状态基本一致,最大水平主应力方向主要表现为北东东至东西向,这与华北的区域应力场相一致;水平应力的梯度大于环渤海圈的平均地应力梯度;研究区浅部三向主应力相对大小以 S H >S h >S v 为主,这有利于逆断层的活动;研究区 K′值和μ m值均较高,分布区间分别为:2.76~3.98和0.47~0.59;陆区断层与区域应力方向均以较大角度相交,处于稳定的状态;海域的北西西向和北东向断层与区域应力场的方向夹角较小,如果区域应力持续增强,将有利于走滑断层的活动,这与震源机制以走滑型地震为主相符。研究结果对研究区内断层稳定性的评价和重大工程的设计及施工都具有重要参考意义。
