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971.
Huaxue Liu Pingping Shen Chunhou Li Zuozhi Chen Zhanhui Qi Honghui Huang 《中国海洋大学学报(英文版)》2016,15(1):171-176
Ciliates are very important components in most marine ecosystem.They are trophic link between the microbial food web and grazing food chain.In this study,ciliates were collected from 11 sites in the southern South China Sea(SCS) during August 25 to September 28,2011.Their composition and distribution at the surface and 75 m deep depth of the ocean were studied.A total of 30 species belonging to 22 genera were identified,and 22 species of 15 genera were Tintinnids.Eutintinnus fraknoii and E.stramentus were the most common species.The other dominants were strombidiids ciliates including Strombidium conicum and S.globosaneum,which were followed by the tide form,Mesodinium pulex.Ciliates abundance ranged from 46 ind L~(-1) to 368 ind L~(-1) in the open sites,46–368 ind L~(-1) at surface and 73–198 ind L~(-1) at 75 m deep layer.In the Yongshu reef,ciliates abundance ranged from 167 ind L~(-1) to 365 ind L~(-1) in the water column,similar to that in Sanya coral reef waters.Ciliates composition showed obvious difference between surface and 75 m deep layer at station S2(P 0.05),while no similar result was observed at other sites.At 75 m deep layer,salinity was negatively related to mixed layer depth(P 0.05),but positively to chlorophyll a concentration(P 0.05),indicating that the change of vertical mixing in water column influenced vertical distribution of ciliates in the southern SCS. 相似文献
972.
北票组是辽西侏罗纪主要含煤地层,大部分学者从植物化石角度论述其时代为早侏罗世,区域上与窑坡组、永定庄组、富县组、三工河组对比。本文从地层层序、岩性、构造演化、古气候演化等角度对北票组的地质时代和区域对比进行了讨论,认为该组为印支期后地壳伸展阶段早侏罗世早—中期兴隆沟组火山喷发之后和中侏罗世中晚期海房沟组、蓝旗组燕山期火山活动之前的含煤盆地沉积产物。前者火山活动在冀北、京西形成南大岭组,在北疆三工河组局部形成火山岩夹层;后者火山活动在冀北、京西形成九龙山组、髫髻山组,晋北形成云岗组、天池河组,北疆形成头屯河组。北票组底部杂色地层化石稀少,有机质含量低,气候应相对干热,北票组(杂色地层以上部分)、海房沟组、蓝旗组植物化石和孢粉证明古气候由温湿向干热逐渐演化,而该特征和中国北方以至全球早侏罗世晚期干热、中侏罗世从早期到晚期由温湿向干热的演化规律—致。从而,北票组底部杂色地层属于早侏罗世晚期并和三工河组、富县组、永定庄组、阳眷组、窑坡组底部对比;北票组杂色地层以上部分属于中侏罗世早期,与西山窑组、延安组、大同组、下花园组、窑坡组(K1砂岩以上部分)对比。 相似文献
973.
974.
975.
乐清湾口海域春秋季甲壳动物的群落结构特征研究 总被引:3,自引:1,他引:2
根据2012年春季和10月在乐清湾口海域开展渔业资源调查所获甲壳动物资料,对乐清湾口海域的甲壳动物的种类组成、优势种、物种数量分布、生物多样性和群落结构相似性等群落结构特征及其影响因素进行了研究。结果表明,调查海域共鉴定出34种甲壳动物,隶属于2目17科23属,春季优势种仅有三疣梭子蟹1种,秋季为日本、口虾蛄、中华管鞭虾、三疣梭子蟹4种,两季优势种更替较显著;秋季物种数较春季丰富,调查水域中心区域物种数较多;秋季甲壳动物生物多样性指数高于春季;甲壳动物群落结构与海洋环境密切相关。乐清湾口海域的甲壳动物以季节性的广温低盐种类为主,该海域位于河口,受瓯江径流影响较大;春季受瓯江径流淡水水团影响,物种较少,而秋季受交汇水团影响,物种丰富;春秋季组内并无明显规律,地形、水深和水系等外部因素对甲壳动物群落结构影响较大。 相似文献
976.
Zhang Xuhui Shao Qianqian Ding Yuanjun Cheng Kun Bian Rongjun Liu Xiaoyu Zheng Jufeng Li Lianqing Pan Genxing 《地球科学进展》2016,31(10):1012-1020
2015 is the International Year of Soil (IYS) adopted by the 378th Congress of the United Nations. The Status of the World’s Soil Resources was released by the Food and Agriculture Organization of the United Nations, which was the policy report about the status of the world soil resources for the first time. The universal values of the global community were strengthened by the challenges for the global society from the risk and safety of the change of soil quality, functions, services and soil health. One third of the world soil resources were suffering serious degradation, which could affect the food security in the future, regional development and local conflicts in the report. The major task of the global monitoring, regulation and management of the world soil resources and the social responsibility of supporting the sustainable soil management by education, research and technology development were highlighted. The social responsibility and global development trends of soil science and management strategies were discussed by the keywords, the distribution of contributing authors and the citation of the references, as well as the main contents of the report. The keywords distribution of the report showed that the focus of the soil research included the change of soil quality, processes, functions and services induced by the natural driving forces, human’s activity and soil degradation, as well as the hotspots covered soil carbon/nitrogen-water-biological pool and distribution related with the biogeochemistry, global climate change and ecosystem functions and human health. The number and structure of the cited papers showed that the integration research based on the mega-data analysis were the prominent development trend of the soil science. The geographic distribution of all the contributing authors showed that dominant discourse of the global soil science were grasped by the developed countries including Europe and the United States, China had just limited effects on the global soil science. It is urgent to promote China’s soil science research and the services for global society. 相似文献
977.
978.
Hao?Shen Jilili?AbuduwailiEmail author Alim?Samat Long?Ma 《Arabian Journal of Geosciences》2016,9(13):625
The Central Asian Arid Zone (CAAZ) located in the temperate desert belt of the Northern Hemisphere is one of the most important sources for global aeolian dust and aerosol. It is widely acknowledged that aeolian dust plays a vital role in the Earth system through participating in the energy and material budget of the planet. Except for the existed natural desert areas, the newly human-induced deserts that originally used to be the bed of terminal lakes (like the Aral Sea, Caspian Sea, Balkhash Lake, etc.) are becoming the much more significant sources for aeolian dust/salt in this region. Dust and associated aerosols have complex impacts on local ecological system and human health for its special chemical composition. In recent years, a slight declining trend of dust storm frequency in the region was reported, which may be explained by the weakened human disturbances in desert areas or climate variations. The dust dynamics in the CAAZ represent considerable variations in both spatial and temporal distribution, which makes it harder to forecast the dust events and mitigate its damages to ecosystems and social economics. Nevertheless, there is not much evidence of its climatic and environmental impacts both on the regional and global scales. Therefore, further related studies and regulation measures in the region are essential and emergent, as well as the strengthening cooperation between the associated countries and organizations. 相似文献
979.
江苏中部海岸潮沟形态对滩涂围垦的响应 总被引:2,自引:0,他引:2
根据2001-2013年江苏中部海岸的遥感影像和野外观测数据,对滩涂围垦影响下潮沟的形态演变过程进行分析。结果显示,研究区潮沟在大规模滩涂围垦影响下整体有明显的退化和消亡趋势,潮沟集水面积由2001年的293.94 km2逐渐降低到2013年的103.40 km2,潮沟长度随着其集水面积的缩减呈幂函数减小(R2=0.98),而潮沟宽度随着潮沟长度和集水面积的变小呈指数方式变窄(R2分别为0.87、0.93),总体上研究区每围垦1 km2滩涂,潮沟长度和宽度分别减小约2.60 km和0.67 m,在整个滩涂围垦过程中,落潮后期潮滩的主要排水方式逐渐由潮沟排水向滩面排水方式转变。江苏中部海岸潮沟形态在统计上具有多尺度分形结构,总体上研究区分纬值从大到小依次为潮沟分维值、各潮沟系统分维值、单支潮沟分维值。研究区潮沟的分维值(无标度区间25~210内)在滩涂围垦影响下呈波动性降低,由2001年的1.26逐渐降低到2013年的1.13,各潮沟系统的分维值随着其分汊个数减少呈线性降低(R2=0.89),各单支潮沟的分维值随着其蜿蜒性减小呈线性降低(R2=0.86)。根据潮沟的退化和消亡过程反推潮沟的起源和发育过程,本研究认为研究区最早出现的一类潮沟可能是陆源水流侵蚀型潮沟,而滩面水流冲刷型和潮流辐聚侵蚀型潮沟是随着潮滩淤积变宽过程逐渐发育的,其最初的发育形态可能是潮滩下部的冲刷凹地。 相似文献
980.
To explore the effects of temperature changes on dinoflagellate bloom succession in the coastal waters of the East China Sea, changes in the growth, photophysiology, and Rubisco gene expression of Prorocentrum donghaiense and Karenia mikimotoi, two harmful algal species, were investigated at different temperatures (16 to 28°C). The maximal specific growth rate and the maximal mRNA expression of Rubisco gene in P. donghaiense and K. mikimotoi occurred at 20 and 24°C, respectively. The photosynthetic activity of P. donghaiense was generally stable, but K. mikimotoi photosynthesis increased when temperatures rose from 16 to 28°C. The effective photochemical efficiency (F q ′ /F m ′ ) and the maximal relative electron transfer rate (rETRmax) of K. mikimotoi increased significantly with increasing temperature, and the lowest and highest values occurred at 16 and 28°C, respectively. It seems that P. donghaiense has higher photosynthetic capacity than K. mikimotoi due to its higher F q ′ /F m ′ , rETRmax, and photosynthetic efficiency (α). However, K. mikimotoi has a higher growth rate than P. donghaiense. These results suggest that the photosynthetic activity and genetic responses of dinoflagellates are species-dependent. It is likely that temperature changes affect species composition during blooms, leading to the observed patterns of bloom succession. 相似文献