台湾以北海域浮游桡足类生物海洋学特征的研究Ⅰ.数量分布   总被引：1，自引：0，他引：1  

杨关铭  何德华  王春生  苗育田  于洪华 《海洋学报》1999,21(4):78-86

根据１９８７～１９９０年间在台湾以北海域进行的６个航次的调查资料,对该海域浮游桡足类数量分布作了探讨,结果表明,本区浮游桡足类丰度在春季最高,冬季最低,夏、秋季介于中间;黑潮锋内侧的桡足类丰度一般高于黑潮锋外侧,较高丰度区的分布具夏季最向外海、冬季最靠近岸、其他两季居中的趋势,这与黑潮锋位的季节摆动趋势基本相一致;浮游桡足类丰度的较高值区一般出现在不同水系的交汇区,尤其是黑潮次表层水涌升域的近岸边缘侧,而在黑潮次表层水的主水体中,因溶解氧含量低等因素,其丰度一般均较低;浮游桡足类丰度垂直分布趋势为随水深增加而减低,生物本身昼夜垂直移动规律可能是局部区域产生异常分布的原因之一．  相似文献   

中沙海域的广角与多道地震探测          下载免费PDF全文

黎雨晗  黄海波  丘学林  杜峰  龙根元  张浩宇  陈瀚  王强 《地球物理学报》2020,63(4):1523-1537

由于浅滩和暗礁广布,中沙海域(环礁区)长期以来处在南海地震探测的空白区域.为了揭示该区域的地壳结构及地层-构造特征,进而全面刻画南海陆缘新生代伸展过程,我们首次在中沙及其邻近海域完成了1条广角地震测线OBS2017-2和4条多道地震测线的数据采集.对得到的海底地震仪(OBS)数据进行了格式转换、位置校正等初步处理,识别了来自地壳深部的震相并对中沙环礁地壳结构进行了正演模拟;对穿过中沙环礁的多道地震剖面进行了地层-构造解释,共划分出6套地层.OBS2017-2测线处理结果显示,其数据质量良好,深部震相清晰,且位于环礁内的台站震相延伸较长,可达100km以上.中沙环礁地壳性质为轻微减薄的坚硬大陆块体,厚度约为25km左右.多道地震剖面显示,环礁之上沉积层厚度较薄,除环礁西南部存在一条基底断裂——"排洪-美溪断裂"外,基本不存在其他构造-岩浆活动.而在环礁坡脚周缘,有广泛的岩浆侵入和喷出体的存在.中沙环礁上较薄的上地壳厚度和沉积特征指示了该区域可能在古新世时期经历的强烈暴露剥蚀作用.中沙海域最新开展的广角和多道地震探测填补了南海地质地球物理研究的空白,为解读该区的构造-沉积演化提供了数据基础.  相似文献   

Fluorescence as a Tool for Tracing the Organic Contamination from Pulp Mill Effluents in Surface Waters     

Eduarda B. H. Santos  Olga M. S. Filipe  Regina M. B. O. Duarte  Helena Pinto  Armando C. Duarte 《洁净——土壤、空气、水》2001,28(7):364-371

Three‐dimensional fluorescence spectra of water samples from an eucalyptus bleached kraft pulp mill and from a river, upstream and downstream of the discharge of the effluent, revealed the existence of a peak at δ_exc = 280 nm and δ_em = 340 nm Δδ = 60 nm), characteristic of effluentπs organic matter. Humic substances were isolated from the effluent by sequential adsorption onto resins XAD‐8 and XAD‐4 in series. Their synchronous fluorescence spectra with Δδ = 60 nm do also exhibit an intense signal at δ_exc = 280 nm (≈ 300 nm in the humic acid fraction). The peak is absent in the spectra of humic substances isolated from a non‐polluted site of the river, but it is clearly seen in the spectra of the humic substances from a site downstream of the discharge of the effluent. Synchronous fluorescence spectra (Δδ = 60 nm) of water samples from the river and its lagoon were recorded and revealed to be an easy and fast way of tracing the organic contamination from the effluent.  相似文献   

Are temporal variations in the nitrate content of UK upland freshwaters linked to the North Atlantic Oscillation?     

D. T. Monteith  C. D. Evans  B. Reynolds 《水文研究》2000,14(10):1745-1749

Synchronous patterns of variation in NO₃ concentration, observed in upland lakes and streams across gradients of climate, altitude, land use and nitrogen deposition over the last decade, show a strong negative correlation with winter values for the North Atlantic Oscillation Index and mean winter temperature. Variations in a longer term stream NO₃ record validate this relationship, and although mechanisms are yet unclear, may be linked to the length of time the soil profile remains frozen during the winter. These findings are of particular significance to our understanding of the relationship between atmospheric N deposition and concentrations and fluxes of NO₃ in runoff, and the potential response to future climatic changes. Copyright © 2000 John Wiley & Sons, Ltd.  相似文献