Dynamics of recruitment of larval and juvenile Cape stumpnose Rhabdosargus holubi (Teleostei: Sparidae) into the Swartkops and Sundays estuaries,South Africa     

Y Kisten  P Pattrick  NA Strydom  R Perissinotto 《African Journal of Marine Science》2015,37(1):1-10

Recruitment of early life stages into estuaries is an integral part of the life cycle of many marine fish species. Although estuaries are naturally environmentally dynamic, they also are subject to anthropogenic disturbances, including land use and climate change, which may affect recruitment. Rhabdosargus holubi is an endemic marine-spawning species predominantly associated with freshwater-rich estuaries which serve as nursery areas for postflexion larvae and juveniles. This study assessed the effect of environmental variables on the dynamics of recruitment of R. holubi larvae and juveniles into the Swartkops and Sundays estuaries, South Africa. Over a period of two years, fyke nets were set at each estuary mouth to monitor movement into the estuaries at each tidal phase over a 24 h cycle during two sampling sessions per season. Rhabdosargus holubi larvae recruited into estuaries primarily in summer and autumn and during the ebb tide at night, while juvenile movements showed no pattern. Salinity, turbidity and temperature were significantly important factors affecting R. holubi recruitment, with pH having no significant effect. Turbidity and salinity are affected by rainfall and freshwater abstraction which may thus influence recruitment. Rhabdosargus holubi is dependent on estuaries, so a combination of future changes in turbidity, salinity and temperature due to predicted climate change may place populations at risk.  相似文献   

Anomozamites (Bennettitales) from Middle Jurassic Haifanggou Formation,western Liaoning,China   总被引：1，自引：0，他引：1  

ZHAO Miao  SUN Chunlin  David L.Dilcher  ZHAO Zhe  NA Yuling 《世界地质(英文版)》2015,18(2)

The Middle Jurassic Hangfanggou Formation is well exposed in Shangsanjiao and Xiasanjiao villages area,Baimashi town of Huludao,western Liaoning,China.Recently,abundant fossil plants were collected from the Hangfanggou Formation.One new species,Anomozamites sanjiaocunensis sp.nov.(Bennettitales),is described in this study.This is the first report of the genus Anomozamites from the Haifanggou Formation based upon the leaf morphology and epidermal structures.The discovery of the new species extends significantly the stratigraphic and geographic distribution of Anomozamites in the Middle Jurassic.It also shows that Anomozamites was a common member of Bennettitales once lived in the Middle Jurassic warm temperate region.The new species also improves the knowledge on understanding the leaf morphology,epidermal features and the diversity of Anomozamites during the Middle Jurassic.The epidermal characters of the new species and its associated plants reveal that the plants grew in a warm and moderately humid environment in the warm temperate zone.The presence of some deciduous plants,such as ginkgoaleans,czekanowskialeans and conifers,indicate the climate with seasonal fluctuations in temperature.  相似文献   

ENVISAT-ASAR数据产品介绍与数据处理     

李苗  臧淑英  那晓东  乔艳雯 《东北测绘》2012,(1):63-65

因ASAR（Advanced Synthetic Aperture Radar）具有全天候、全天时、穿透性强、多种入射角、宽幅成像、多模式、多极化等优势,而成为遥感研究和应用的热点。它是当今最先进的合成孔径雷达数据。本文对ENVISAT的ASAR数据类型进行介绍,并利用欧空局开发的雷达处理工具NEST（Next ESA SAR Toolbox）软件包和ENVI软件对雷达数据进行辐射定标、影像校正和图像滤波处理,为ASAR数据处理方法提供了有益补充。  相似文献   

Cooling of hybrid stars with spin down compression     

Miao Kang  Xiao-Dong Wang  Na-Na Pan 《中国天文和天体物理学报》2009,9(12)

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半干旱区农田和草地与大气间二氧化碳和水热通量的模拟研究   总被引：7，自引：1，他引：6  

姜纪峰  延晓冬  黄耀  郭维栋  刘辉志  王淑瑜 《气候与环境研究》2006,11(3):413-424

集成生物圈模型(IBIS)是目前最复杂的基于动态植被模型的陆面生物物理模型之一。通过应用该模型对国际协调强化观测计划(CEOP)半干旱区基准站之一的吉林通榆观测站(44°25′N,122°52′E)草地和农田生态系统2003年全年的CO2和水、热通量变化进行模拟,并将结果与涡度相关法测定的观测值进行了对比分析,以检验IBIS模型在半干旱区的模拟能力。对比结果表明:除CO2通量模拟结果不够理想外,IBIS模型较好地模拟了通榆观测站的感热通量和潜热通量。模拟与观测比较的相关系数均通过了0.05以上显著性水平的信度检验。总体上看,模型对农田生态系统模拟的偏差小于对退化草地的模拟。  相似文献   

The use of environmental isotopic (C, Sr, S) and hydrochemical tracers to characterize anthropogenic effects on karst groundwater quality: A case study of the Shuicheng Basin, SW China   总被引：10，自引：0，他引：10  

Xiao-Dong Li  Cong-Qiang Liu  Masuda Harue  Si-Liang Li  Xiao-Long Liu   《Applied Geochemistry》2010,25(12):1924-1936

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聚类分析在物源分析中的应用——以伊通盆地鹿乡断陷为例     

丁鸿儒  郭巍  刘群  那晓敏  马琳  孙守亮 《世界地质》2010,29(3):466-472

鹿乡断陷近年来虽在油气勘探方面取得了一系列成果,但该区存在多物源方向交汇、沉积体系划分不清晰;而经典的物源分析方法操作复杂,可靠性差。笔者应用统计学方法,对研究区重矿物的相对含量进行聚类分析,结合研究区砂岩等厚图,对鹿乡断陷双阳组各段的物源方向进行分析,结果表明:在双阳组一段沉积时期,研究区存在西南、南部和东部3个物源方向;在双阳组二段沉积时期,研究区存在东部、南部、西南和西北4个物源方向;在双阳组三段沉积时期,研究区存在东部和西北部2个物源方向。双阳组沉积时期,西北和南部方向物源的沉积物供给呈现"弱--强--弱"的变化特点,东部方向物源的沉积物供给不断减弱。沉积体系的规模受控于沉积速率。  相似文献   

北极放线菌AFN2001培养基和发酵条件的优化实验     

那广水  张婷  叶亮  沈晶  姚子伟  奚涛 《海洋学研究》2008,26(4):66-71

从北极王湾地区湖泊沉积物中分离出的菌株AFN2001,其代谢产物对金黄色葡萄球菌有明显的抑制作用,抑菌圈直径达23 mm,对大肠杆菌和绿脓杆菌没有抑制作用。为了确定AFN2001菌株发酵获得最多的活性物质,对单因素确定的营养因素淀粉、黄豆浸出物、蔗糖和NaNO3及另外的MgSO4、K2HPO3和水质进行7因素3水平正交优化实验。对结果进行直观分析及方差分析,发现NaNO3对发酵液活性的影响最大,其次依次为淀粉、K2HPO3、MgSO4、黄豆浸出物、蔗糖和水质对发酵液活性的影响;并找出产生活性物质的最佳组合。确定优化培养基(淀粉为10 g、蔗糖为10 g、黄豆浸出物为6 g、MgSO4为0.5 g和自来水为1 000 mL)和优化发酵条件(发酵温度为28℃、起始pH值为6.0和装液量为50%)。利用优化培养基和优化发酵条件发酵的菌株AFN2001,其发酵液的抑菌活性是基础培养基发酵液的1.6倍。  相似文献   

Characteristics　of　tectonic　deformation　field　about　strike－slip　earthquake－generating　structure　in　the　Chinese　mainland     

环文林  张晓东  宋昭仪 《地震学报(英文版)》1995,8(2):175-184

Ｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｔｅｃｔｏｎｉｃｄｅｆｏｒｍａｔｉｏｎｆｉｅｌｄａｂｏｕｔｓｔｒｉｋｅ－ｓｌｉｐｅａｒｔｈｑｕａｋｅ－ｇｅｎｅｒａｔｉｎｇｓｔｒｕｃｔｕｒｅｉｎｔｈｅＣｈｉｎｅｓｅｍａｉｎｌａｎｄ环文林，张晓东，宋昭仪Ｗｅｎ－Ｌｉｎ...  相似文献   

EFFICIENCY OF NITROGEN REMOVAL IN CONSTRUCTED WETLAND：A SIMULATION STUDY IN THE WEST JINLIN, CHINA     

ZHANGHu-Cheng YUMu-Qing TIANWei YUJian FUYou-Bao WANGXiao-Dong 《湿地科学》2004,2(4):309-313

Plenty of inorganic nitrogen in wastewater can cause the eutrophication in water bodies, so it is an important task to remove nitrogen. Purification role was realized by absorption, filtration, depositon, evaporation, nitrification and denitrification of microbes. Although the studies of Phragmites austrilis bed in the constructed wetland are popular, the purification performances of constructed wetland filled by saline-alkali soil substrate are less reported. In the paper, the purification efficiency of nitrogen with Phragmites austrilis bed in the constructed wetland filled by saline-alkali soil substrate was discussed through a simulation study. Results to date indicated that the first order plug flow model was adequate to describe the nitrogen removal. The experiment showed that the diminishing concentration of TN, NO2-N, NO3-N, NH4-N were closely related to hydrological retention time (HRT), the correlation coefficient was R^2 = 0.98499, R^2 = 0.9911, R^2 = 0.89407 and R^2 = 0.95459, respectively. According to the data, the most suitable hydrological retention time (HRT) for this kind of constructed wetland should be determined to 4 days. In addition, the experiment showed the purification efficiency of nitrogen has very broad range and drastic vibration, TN( 17 % - 79 % ), NO2-N (33%-98% ), NO3-N (13%-93% ), NH4-N (28%-64% ). The study will promote wetland‘s design and operation procedures in large saline-alkallne soil areas.  相似文献