水体溶解态黑碳的分子标志物苯多羧酸的气相色谱-质谱分析

苯多羧酸分子标志物法是定量水体中溶解态黑碳的常用方法,然而由于部分苯多羧酸,尤其是硝基苯多羧酸商业化标准品的缺失,采用该方法定量溶解态黑碳仍需进一步完善和优化。本文通过已有的苯多羧酸商业化标准品,建立了气相色谱-质谱联用仪(GC-MS)分离和定量 9 种缺少商业化标准品苯多羧酸的分析方法。并首次将菲-D10 作为溶解态黑碳的替代物,指示苯多羧酸法定量溶解态黑碳过程中的损失率。结果表明,该方法具有良好的重现性(RSD=10.34%),方法检出限为 0.67~5.38 ng/L。本文采用该方法分析了大亚湾表层水体溶解态黑碳的分布特征,其浓度范围为 30.38~46.19 μg/L,平均值为(38.93±6.17)μg/L,空间分布表现为从湾内到外海递减的趋势。     

小型水坝拆除后河貌演变模拟分析——以西河水坝为例

小型水坝随着服役时间的增长,其面临的安全、经济和生态方面问题日益突出,针对一些修复价值较低的病险水坝,实施降等或报废拆除已成为一种综合最佳的管理措施。拆坝后,原库区大量淤沙无控释放将改变原有河道形态,对水生生物栖息地造成影响。为预测拆坝后河道在不同时间尺度上的变化特征,以长江流域乌江水系内的西河水坝为研究对象,建立二维水沙数学模型,分别研究了拆坝后水沙输运造成的短期和长期河床形态变化。结果表明:拆坝后短期内,坝址上游主河道发生了强烈的冲刷下切,且水库淤沙前缘部分出现了显著的淤积抬高,相比而言,坝址下游河床变化并不明显,只有坝下河段及河口附近出现较显著的泥沙淤积;在拆坝后长期的河床演变过程中,坝址上下游河道均发生了不同程度的冲刷下切,拆坝2年后下游河床逐渐趋于稳定,而上游主河道由冲刷下切转化为冲淤交替的演变趋势,河床形态不断调整变化。本研究可为病险坝和小水电报废拆坝后的河道治理、水生生物栖息地修复提供参考依据。     

珠江三角洲网河区低水位时空变化规律

珠江三角洲近30年的大规模无序采挖沙改变了网河区水多沙少、河势稳定的演变趋势,促使河床由缓慢淤积转变为大幅下切,低水位出现明显下降。这种人为作用已涵盖并远超同期河流自然演变的程度,对取水供水、生态保护、航运保障等产生了较大影响。在总结河口三角洲地区水位变化研究的基础上,以珠江三角洲网河区为例,按低水位变化划分为常年潮流段、季节性潮流段和常年径流段。其中,常年潮流段基本不受采砂影响;季节性潮流段依据径流、潮流比例,越靠近枯水潮流界,低水位变化越大;常年径流段还存在溯源冲刷引起的低水位下降。结合水沙变异过程,试图探讨水动力对河床急剧演变的响应机制,以期为通航低水位设计提供依据。     

深圳填海造地动态变化及其驱动因素分析

基于海岸地貌基本概念界定填海造地范围在现代海岸带平均高潮位以下。基于多期遥感影像,利用单波段影像提取及影像二值化处理辨识深圳填海造地的动态变化数据。根据1978-1985年、1986-1994年、1995-1998年、1999-2004年4个时间段的填海数据解析结果,分析了在深圳这一典型的快速城市化地区城镇化进程中填海造地的起始阶段、快速阶段、增速阶段到理性阶段的阶段性过程。在此基础上,对深圳填海造陆的驱动力进行分析,建立了填海造地的综合驱动框架模型;归纳了区位因素、政策因素、社会经济因素和自然生态因素四大填海驱动力,并结合深圳的城市发展进程与深圳填海的不同阶段对每一因素的驱动作用进行了剖析。     

广西龙滩库区库水加卸载过程中地下电阻率的变化

在广西龙滩库区于2009年至2010年初库水加卸载过程中,对4个测点进行了3期次大地电磁观测,观测频段为320Hz～1000s。观测结果显示库水加卸载过程中深部介质电阻率变化与岩性有关。在同一岩性出露区域的3个测点,库水加卸载的3期次观测的视电阻率数值在频率1Hz以下频段变化明显,库水水位最高时段测量的视电阻率值最低,水位下降阶段测量的视电阻率数值最高,最低水位测量的视电阻率数值居中。实测结果表明:在广西水库水位加卸载过程的不同时段,库区岩性、库容面积和自重变化对地下水的连通和渗透有较大影响,从而导致地下一定深度下的介质电性发生变化。     

Identification and characterization of the Vibrio anguillarum prtV gene encoding a new metalloprotease

We cloned and sequenced a prtV-like gene from Vibrio anguillarum M3 strain.This prtV gene encodes a putative protein of 918 amino acids,and is highly homologous to the V.cholerae prtV gene.We found that a prtV insertion mutant strain displayed lower gelatinase activity on gelatin agar,lower protease activity against azocasein,and lower activity for four glycosidases.This prtV mutant strain also had increased activity for two esterases in its extracellular products,as analyzed by the API ZYM system.In additi...     

Re-Examination of the Oil and Gas Origins in the Kekeya Gas Condensate Field, Northwest China–A Case Study of Hydrocarbon-Source Correlation Using Sophisticated Geochemical Methods

This work discussed the origins, alteration and accumulation processes of the oil and gas in the Kekeya gas condensate field based on molecular compositions, stable carbon isotopes, light hydrocarbons, diamondoid hydrocarbons and biomarker fingerprints. A comparison study is also made between the geochemical characteristics of the Kekeya hydrocarbons and typical marine and terrigenous hydrocarbons of the Tarim Basin. Natural gas from the Kekeya gas condensate field is derived from Middle–Lower Jurassic coal measures while the condensates are derived from Carboniferous–Permian marine source rocks with a higher maturity. In the study area, both natural gas and condensates have experienced severe water washing. A large amount of methane was dissolved into the water, resulting in a decrease in the dryness coefficient. Water washing also makes the carbon isotopic compositions of the natural gas more negative and partially reverse. Considering that the gas maturities are higher than once expected, gas generation intensity in the study area should be much stronger and the gas related to the Jurassic coal measures could promise a greater prospecting potential. As a result of evaporative fractionation, the Kekeya condensates are enriched in saturates and lack aromatics. Evaporative fractionation disguises the original terrigenous characteristics of the light hydrocarbons associated with the natural gas, making it appear marinesourced. Thus, alteration processes should be fully taken into consideration when gas–source correlations are carried out based on light hydrocarbons. With the condensates discovered in the study area all being "migration phase", the pre-salt Cretaceous and Jurassic reservoirs may promise great exploration potential for the "residual phase" hydrocarbons. This research not only is of significance for oil and gas exploration in the southwest Tarim Basin, but also sheds light on the oil/gas-source correlations in general.     

山东晚白垩世一新的巨龙类恐龙

记述了产自山东诸城上白垩统王氏群中一个较完整的蜥脚类恐龙肱骨(ZJZ-57)。它具有一些进步特征,如肱骨三角胸嵴向远端扩展,肱骨近端外侧1/3处发育隆凸,表明其属于较进步的巨龙类成员。另外,它具有一些独特的鉴定特征组合区别于其他任何巨龙类:近端横向强烈扩展,近端最大宽度与骨干长度之比为0.55;骨干粗壮,粗壮指数为0.39。综合研究表明,ZJZ-57所属个体代表了一种新的巨龙类恐龙:臧家庄诸城巨龙(Zhuchengtitan zangjiazhuangensis gen.et sp.nov.),它可能与Opisthocoelicaudia的亲缘关系较接近。这是山东晚白垩世地层中首次发现的巨龙类恐龙。     

我国海洋地质调查研究新进展

近10年来,我国海洋地质工作在海岸带、近海与管辖海域、大陆架边缘海和深海大洋开展了地质构造、矿产资源、环境灾害和探查技术及仪器设备等方面的调查研究和研发,取得一系列重要成果。如历时8年的“我国近海海洋综合调查与评价”专项(908专项),完成了1∶100万管辖海域的16个图幅、1∶25万13个图幅的综合调查和9个区块海砂资源评价; 在南海北部琼东南盆地发现了3个大气田; 开展了海岸带环境地质调查评价与图集(1∶400万)编制; “南海深海过程演变”专项研究与南黄海陆架区科学钻探均有新发现; 海底石油勘探与开发技术(“海洋石油981”钻井平台)、南海北部海域天然气水合物探测技术及发现(Ⅱ型天然气水合物、可燃冰冷泉)、南海天然气水合物试采成功,以及海底探测技术与采样设备的研发等等取得了实质性进展或突破。这些重要成果极大地提高了我国海洋地质调查的程度、研究水平和综合实力。     

Flow Experience Study of Eco-tourists: A Case Study of Hunan Daweishan Mountain Ski Area

Mountain skiing has become a popular winter ecotourism activity in China. Studying the loyalty of eco-tourists from the perspective of tourist experience is important to the continued development of mountain ski tourism. Based on the flow experience theory, we developed and tested a structural equation model to examine relationships among flow experience, positive emotions and the loyalty of eco-tourists. Survey data from 324 eco-tourists with skiing experience at Daweishan Mountain Ski Resort was used for exploratory factor, confirmatory factor and path analyses. Results revealed five dimensions of flow experiences of eco-tourists: Concentration on task at hand, Loss of self-consciousness, Transformation of time, Autotelic experience, and Challenge-skill balance. As hypothesized, influences of Transformation of time, Autotelic experience and Challenge-skill balance on positive emotions were significant and positive. Concentration on task at hand, Autotelic experience, Challenge-skill balance and positive emotions positively influenced the loyalty of eco-tourists. Suggestions for developing ecotourism products are discussed such as designing a conductive environment to activate flow experience, providing personalized service to promote positive emotion, and developing experiential tourism activities.