近海生态系统的人为营养盐输入及其控制对策浅析

人为活动每年新增大量的活性氮、磷,导致全球氮、磷循环失衡,新增活性氮、磷主要来源于合成氮肥的生产和施用、畜肥的施用、具固氮能力的农作物如豆科植物等的大规模种植,以及化石燃料燃烧产生的氮氧化物等,而农作物生产与畜禽养殖是改变全球氮、磷循环的主要原因。随着生活污水排放量和化肥施用量的激增,大量氮、磷进入近海,导致营养盐污染和富营养化,这已成为全球性的海洋生态环境问题,通过河流径流和大气沉降进入近海生态环境中的新增氮和磷一半以上与人为活动有关。本文以波罗的海和东海为例,分析了发达国家和发展中国家近海的富营养化问题,研究表明从源头缓解富营养化的对策应同时聚焦氮与磷负荷的削减,具体措施包括降低农业生产活动中化肥的土壤渗漏、合理施肥、种植多年生植物和种植休耕季覆被作物等。     

海洋酸化背景下海水pH值测定技术的发展和优化

海水pH值直接指征海洋酸化程度,是对生物地球化学循环具有重要意义的海水碳酸盐体系进行定量描述的重要指标之一。文章概述pH值的定义及其发展,解析不同pH标度的换算和选取;详述采用电极电位法和分光光度法测定海水pH值的原理和特点;根据目前国际海洋酸化监测和研究的新要求以及我国近海海域海洋酸化形势,提出我国现行标准存在的问题,基于此提出全程恒温测样和从NIST标度向总氢离子浓度标度转化的优化建议,以提高我国海水pH值测定的准确度。     

新疆准噶尔盆地西北缘石炭纪浊积岩系中遗迹化石的发现及其意义

准噶尔盆地西北缘石炭纪地层主要由碎屑岩组成,沉积厚度5000—7000m,在下石炭统和中石炭统中首次发现了包括浊流在内的重力流沉积和平流岩,大量的深水相遗迹化石。说明盆地西北缘是深水沉积,而非前人普遍认为的属浅水沉积环境。     

钪－4，5－二溴苯基荧光酮－CTMAB－吐温－60多元配合物的分光光度法研究

研究结果表明，在混合表面活性剂ＣＴＭＡＢ－吐温－６０存在下的ｐＨ５．７～６．５的缓冲介质中，Ｓｃ（Ⅲ）与４，５－二溴苯基荧光酮（ＤＢＰＦ）形成高灵敏的多元配合物，其ε＿（５９０）＝２．２６×１０￣５Ｌ·ｍｏｌ￣（－１）·ｃｍ￣（－１），组成比为：Ｓｃ：ＤＢＰＦ：ＣＴＭＡＢ＝１：２：４。采用混合表面活性剂使增溶增敏作用更为显著，并加速了显色反应，增强了配合物的稳定性。而Ｎａ＿２ＳＯ＿４的加入能显著地提高体系的灵敏度。Ｓｃ量在０～０．３６ｕｇ／ｍｌ范围内遵守比尔定律。方法可直接测定合成混合稀土中的Ｓｃ，回收率在９８％～１０５％；结合沉淀分离和ＰＭＢＰ萃取分离，实现了地质试样中痕量Ｓｃ的测定。     

A Preliminary Analysis of Features and Causes of the Snow Storm Event over the Southern Areas of China in January 2008

Four successive freezing rain/heavy snowfall processes occurred in the southern part of China from 11 January to 2 February 2008 （named ＂0801 Southern Snow Disaster＂ hereafter）, during which a large-scale blocking circulation lasted for a long time over the mid-high latitudes of the Euro-Asian continent. This severe event is featured with a broad spatial scale, strong intensity, long duration, and serious damage. During the event, the blocking situation in the mid-high latitudes maintained quasi-sationary, but weather systems in the lower latitudes were active. Abundant water vapor was supplied, and favorable weather conditions for ice storms were formed over the large areas across the southern part of China. The results in this paper demonstrate that the significant factors responsible for the abnormal atmospheric circulation and this severe event include： 1） the very active Arctic Oscillation （AO）, which helped the permanent maintenance of the planetary-scale waves; 2） the continuous transfer of negative vorticity from the upstream region around 50°E into the blocking area, which caused the blocking situation reinforced repeatedly and sustained for a long time; and 3） the active air currents south of the Tibetan Plateau, which ensured abundant moisture supply to the southern areas of China. The 0801 Southern Snow Disaster was accompanied by extremely severe icing. In this paper, the data from Cloud-Profile Radar onboard the satellite CloudSat are used to study the dynamic and microphysical features of this event. The results show that there existed a melting layer between 2 and 4 km, and ice particles could be found above this layer and in the layer near the ground surface. Surface temperature kept between -4℃ and 0℃ with relative humidity over 90%, which provided the descending supercooled waterdrops with favorable synoptic and physical conditions to form glaze and ice at the surface via freezing, deposition and/or accretion. Causes of the event might be, as a whole, traced back to the planetary-scale systems. The study on the polar vortex anomaly in this paper reveals that changes in the polar vortex in the stratosphere preceded those in the troposphere, especially in early December 2007, while the intensification of the polar vortex in the troposphere delayed dramatically until middle January and early February of 2008. This implies that changes in the polar vortex in the stratosphere may be a precursor of the ensuing severe event and a meaningful clue for extended forecasts of such a disaster.     

《遥感大词典》的诞生侧记——向中国环境遥感学会十周年献礼

陈述彭教授主编的《遥感大词典》由科学出版社于1990年8月出版。该词典包括三大部分:遥感基础,遥感技术及遥感应用。有1060页,5600条词目,彩色像片24页及许多表格、插图,并附有汉、英、法、德、俄五种文字索引。近200名专家、学者参与了本项工作。 本文叙述了《遥感大词典》编辑出版始末,并总结了编辑出版过程中的经验教训。本文生动描述了词典编撰目的,条目筛选和释义及技术术语统一规范的做法。在内容安排、编码、制版及印刷方面采用的一些新方法和新技术,保证了词典的高质量。 本文特别强调了《遥感大词典》是遥感界同仁执著奉献和国内国际大协作的成果。     

Use of QSAR and SSD methods on deriving predicted no-effect concentrations in seawater and sediment for ten individual parent- and alkyl-PAHs and a case study on the assessment of their ecological risks from the Dalian Bay,China

Parent and alkylated polycyclic aromatic hydrocarbons (alkyl-PAHs), which are a class of important toxic components of crude oil especially in the marine environment, exhibit adverse effects on aquatic life and potentially pose a human health risk. However, the lack of chronic toxicity data is one of the hindrances for alkyl-PAHs when assessing their ecological risks. In this study, predicted no-effect concentrations (PNECs) in seawater and marine sediment for ten parent- and alkyl-PAHs were derived by applying species sensitivity distributions (SSDs) and quantitative structure?activity relationships (QSARs). The local area, Dalian Bay, where an oil-spilled accident happened in 2010, was chosen as a case site to assess ecological risks for ten PAHs in surface seawaters and marine sediments. Their PNECs in seawater and sediment for protecting aquatic organisms in marine ecosystems were calculated and recommended in the range of 0.012?2.79 μg/L and 48.2?1337 ng/g (dry weight), respectively. Overall, the derived PNECs for the studied PAHs in seawater and marine sediment were comparable to those obtained by classical methods. Risk quotient results indicate low ecological risks to ecosystems for ten parent- and alkyl-PAHs in surface seawaters and surface sediments from the Dalian Bay. These findings provide a first insight into the PNECs and ecological risks of alkyl-PAHs, emphasizing the role of the computational toxicology in ecological risk assessments. The use of QSARs has been identified as a valuable tool for preliminarily assessing ecological risks of emerging pollutants, being more predictable of real exposure scenarios for risk assessment purposes.     

Pb isotopic dating of some Precambrian rocks from North China—An ensuing discussion on Precambrian Geochronological Scale of China

Pb isotopic ages of some Precambrian rocks from North China were determined. New data from the Chuanlinggou Formation of the Great Wall Group in the Yanshan region, together with published data, show that their whole-rock Pb-Pb isochron age is 1,922±92 (δ) m.y. Thus, 2,000±100 m.y. as the lowest age of the Sinian Geochronological Scale of China is important. In view of the fact that the whole-rock Pb-Pb isochron age from the Liaohe Group in Liaoning Province is estimated to be 1,977±49 (δ) m.y., which is in agreement with the possible maximum deposition age calculated from Rb?Sr data, we prefer to consider the Liaohe Group to be Sinian rather than pre-Sinian in age. Zircon, apatite and other minerals from the Tiejiashan granitic gneiss at Anshan, Liaoning Province, lie on two U-Pb discordant lines with ca. 3,300 and 2,800 m.y. respectively. Zircon, on the discordia with 3,300 m.y., is non-magnetic and free from dark inclusions. Apatite with common Pb isotopic composition, lying on the line of older age, is close to the concordia, indicating that it has not undergone any geological thermal events since it was formed. Zircon and apatite with inclusions and magnetism lie on the discordia of younger age. A U-Pb age of ca. 3,300 m.y. for the Tiejiashan granitic gneiss seems to be possible. However, it is necessary to examine the ages of these rocks with Rb?Sr and other methods in the future. A precursory Precambrian Geochronological Scale of China is propsed based on the Sinian Geochronological Scale of China published in 1977^[1] as well as on new data from this study.     

Dynamic Changes of Sediment Discharge and the Influencing Factors in the Yellow River,China, for the Recent 90 Years

The dynamic changes in the sediment discharge over 90 years from 1919 to 2008 in the Yellow River in China were assessed on the basis of annual rainfall series and annual sediment series in Shan County hydrological station. The key factors affecting sediment discharge, such as rainfall, and human activities were studied. Anomaly accumulation method and double mass curve were employed to test the stage changes of sediment discharge, and to determine the main factors of sediment decline. Results showed that the annual average sediment discharge under natural conditions was about 16 × 10⁸ t, but the measured annual average sediment during 1919–2008 was 12.71 × 10⁸ t. The highest annual average during the study period was 39.10 × 10⁸ t in 1933 while the lowest was 1.77 × 10⁸ t in 2008. Sediment discharge in the Yellow River experienced two low sediment stages (1924–1931 and 1979–2008) and a high sediment stage (1932–1971), respectively. Since 1979, there was a significant decreasing trend in the sediment discharge, and the main influencing factor was fierce human activities. Annual average sediment discharge in the post‐development period (1979–2008) was 69.7% lower than that in the pre‐development period (1919–1978), with average reduction of 81 and 19% caused by human activities and rainfall, respectively. These results provide important evidence for making protecting policy for water resources quality and environmental safety of the Yellow River.     

四川盆地南部二叠系茅口组碳酸岩岩石学与储集性质

概述茅口组沉积时,四川盆地为一沉积碳酸盐的浅海台地,东北与已上升为陆的中朝陆台毗邻。北有秦岭、西有康滇、东南有雪峰等古陆呈岛链孤立于广阔浅海中。有的已经沉没水中。海水来自特提斯海,从西和西南进入本区,再向东流入杨子海槽。陆源物质主要来自中朝陆台和邻近古陆。