岩溶水体惰性有机碳含量及其存在机理     

李强  黄雅丹  何若雪  于奭  宋昂  曹建华 《岩矿测试》2018,37(5):475-478

正通常认为全球超过1000 m的海洋深处稳定存在着不超过42μmol/L的溶解有机碳,并被认为是微生物难以利用的惰性溶解有机碳[1-2]。这为进一步评估水圈溶解有机碳的稳定性提供了研究依据[3]。河流不但是陆地水的主体、水圈的重要组成部分,而且还是海洋-陆地物质和能量交换的主要通道。近年来,河流的自然性质和作用过程不断受到人文活动的影响,特别是河流筑坝引发的"水库效应"[4-5]。然而"水库效应"下岩溶区筑坝河流中  相似文献   

Effect of parental hypoxic exposure on embryonic development of the offspring of two serpulid polychaetes: Implication for transgenerational epigenetic effect     

J.Y.S. Leung  S.G. Cheung  J.W. Qiu  P.O. Ang  J.M.Y. Chiu  V. Thiyagarajan  P.K.S. Shin 《Marine pollution bulletin》2013

Sperm production and motility, fecundity, and egg size, complexity and viability of serpulid polychaetes Hydroides elegans and Hydroides diramphus after 2-week treatment to hypoxia (2 mg O₂ l⁻¹) was compared with those under normoxia (6 mg O₂ l⁻¹). Despite reduced fecundity, the effect of parental hypoxic exposure on gamete quality was not discernible for both species. However, regardless of their subsequent dissolved oxygen environment, eggs spawned by H. elegans after hypoxic exposure were found to have lower fertilization success, slower embryonic development and a significantly higher yield of malformed embryos than those with a parental normoxic treatment. In contrast, neither fertilization success nor rate of embryonic development was affected for H. diramphus. The results implied that hypoxia was a potential stress reducing the recruitment of H. elegans through non-adaptive epigenetic effect, whereas H. diramphus was a more tolerant species to survive hypoxic events.  相似文献   

Seismic performance of masonry buildings during the 2007 Bala,Turkey earthquakes     

Ali?UralEmail author  Adem?Do?angün  Halil?Sezen  Zekai?Ang?n 《Natural Hazards》2012,60(3):1013-1026

A field investigation was conducted near the town of Bala after two strong earthquakes struck the region on December 20 and 27, 2007. The main objectives of this study are to present the results of the field investigation and examine the characteristics of the recorded ground motions and the corresponding response spectra. The focus of the research was on the causes of damage and failures commonly observed in masonry structures. This study classifies single family masonry dwellings in rural areas and investigates the seismic damage in unreinforced masonry structures. Turkish Earthquake Code requirements for masonry buildings are summarized and compared with the field observations. Our field investigation showed that there has been lack of quality control and regulation for the masonry construction. Diagonal shear cracking and out-of-plane failure were the two major factors that contributed to widespread damage in masonry structures.  相似文献   

自贡市龙潭镇土壤中重金属的地球化学基线及污染状况研究     

李昂  施泽明  倪师军 《物探化探计算技术》2012,34(4):470-474,369

地球化学基线是区分地球化学背景和异常的重要参数.在采集和测试自贡市龙潭镇内168个表层土壤样品的基础上,采用了地质统计学方法建立了研究区内重金属元素As、Cd、Cr、Pb、Hg、Cu、Ni、Zn的地球化学基线.在此基础上,应用地质累积指数方法评价了表层土壤重金属的污染状况.结果表明:区内各重金属元素基线值为As(3.86 μg/g)、Cd(0.183μg/g)、Cr(66.41 μg/g)、Pb(28.19 μg/g)、Hg(0.037 μg/g)、Cu( 23.1 μg/g)、Ni(24.5 μg/g)、Zn(62μg/g);研究区内Cd和Hg的污染较突出,各重金属元素的地质累积指数排序为:Cd＞H g＞Zn＞Cu＞As＞Cr＞Ni＞Pb.  相似文献   

甘肃省岷县两处滑坡普适型监测预警研究     

侯圣山  李昂  刘明学  陈亮  冯振  王立朝 《地质论评》2024,70(S1):208-210

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