抚仙湖水温跃层研究

通过自动监测数据(2012-2013),研究了抚仙湖水温跃层的统计规律,给出了温跃层的出现、发展和消失的统计结果,水温跃层一般出现在5月~12月,并且随着时间推移而逐渐下移。与此同时,还分析了温跃层的层次和震动特性,水温跃层一般在40m之上,极少会出现在40m以下,并且会在凌晨出现双层现象,但是不能持久存在,很快就会恢复成单层,在白天温跃层保持单跃层并且比较稳定。该结果有利于提高对于抚仙湖的水体特征认识,加快综合利用湖泊资源的进程。     

应用时间序列分析法对太湖叶绿素-a含量的动态研究

叶绿素-α是湖泊浮游植物现存量的重要指标,其含量能反映水中浮游植物的丰度和变化规律。研究叶绿素含量的动态变化,可以有效防止、监控湖泊富营养化的发生。以太湖为研究对象,根据其营养水平进行分区,使得不同区域内叶绿素的浓度不同,而同一区域内浓度大体一致,然后利用地理信息系统技术对每个区域内未采样点的叶绿素浓度进行插值,取区域内所有栅格的平均值作为其最终浓度。应用时间序列分析方法对太湖1998-2004年每月的叶绿素含量进行动态模拟,建立各湖区的预测模型。结果表明,中营养区I符合MA（1）模型,轻富营养区Ⅱ和中富营养区Ⅲ符合AR（1）模型,富营养区Ⅳ符合MA（5）模型,重富营养区V符合AR（6）模型。由此预测出2005年各湖区总叶绿素的含量,经前10个月实测数据的验证说明,所建模型在一定程度上能反映太湖各区域叶绿素浓度的变化。     

The benthic macrofauna of the St. Lucia Estuary during the 2005 drought year

The St. Lucia Estuary is the largest estuarine system in Africa. The estuary is part of the Greater St. Lucia Wetland Park, which has been declared a World Heritage Site. This ecosystem has been subjected to severe drought conditions over the last four to five years, resulting in its mouth being closed off from the ocean in June 2002 for a period of over four years. The main aim of this study was to document the effects of the prevailing drought on the macrofauna of the system, since the last work on this benthic component had been undertaken over a decade ago, during a normal-to-wet phase. Macrofauna samples together with physico-chemical data were collected at representative sites in the Narrows, and the South and North lakes in February, April, August and October 2005. The drought exerted a strong influence on the system, leading to hypersaline conditions developing in its northern regions (maximum of 126 at Hell's Gate), and to the loss of aquatic habitat. Ordinations and clustering indicated that the macrofauna of the system could generally be separated into three clusters viz. (1) the Narrows and the southern portion of South Lake, (2) the northern half of South Lake, and (3) the North Lake–False Bay complex. Multivariate correlations indicated weak relationships between macrofaunal community structure and physico-chemical parameters. The distinction in macrofaunal assemblages between these clusters was probably caused by these habitats being physically separated at the peak of the drought, with no water flow between them, thereby preventing exchange of planktonic larvae and retarding colonisation of habitats. There was a northward decline in taxonomic richness and diversity of macrofauna in the system, which correlated positively with water depth and negatively with the biomass of microphytobenthos. It is evident that the drought structured macrofauna communities primarily through its effects on water depth and habitat fragmentation. The results of this investigation provide valuable information regarding the effects of droughts on estuarine–lake systems and the possible mechanisms by which they occur.     

大布苏湖全新世沉积岩心的碳酸盐含量与湖面波动

大布苏湖是我国东北地区极为罕见的盐湖，通过对该湖现代湖盆碳酸盐沉积相的分析，以及钻孔岩心碳酸盐含量和^14C年代的测定,探讨了大布苏湖全新世湖面波动与环境演化的过程。结果表明，大布苏湖有两次高湖面时期，分别为10450－7260和5400－3600aBP，湖泊水位稳定在125m以上，这两个时期也是松嫩沙地古土壤集中发育的时期，晚全新世以来，大布苏湖明显萎缩，气候向干燥方向转化。     

巢湖沉积物粒度特征与沉积环境

利用巢湖湖底柱样沉积物的粒度资料分析了巢湖湖底沉积物粒径的组成、大小等粒度特征;初步探讨了柱样采样点位置的沉积环境及其沉积过程,以期能为巢湖流域恢复过去环境变化提供参考。通过对沉积物粒度实验分析发现,巢湖靠近河口地区的沉积物粒度在深度上变化幅度大,颗粒物相对较粗,而在湖心位置,沉积物随深度变幅小、连续性好,沉积物的颗粒细。两者的差别分别反映了它们之间不同的沉积环境。     

新疆库车盆地古近纪—新近纪盐湖成钾与靶区预测

库车前陆盆地位于塔里木盆地北部,属于副特提斯域,古近纪受副特提斯海海水补给,古近纪—新近纪发育巨厚蒸发岩。研究显示,库车盆地始新世和中新世古盐湖卤水已演化至钾盐析出阶段,在地层中广泛发现了原生钾盐矿物,如钾石盐、光卤石、杂卤石等;通过岩芯岩屑地球化学及矿物学分析,基本确定了至少3个富钾层或成钾层位,其中始新统中上部两个和中新统中上部一个,钾离子含量最高达3%,另外,上新统可能存在一个成钾层位。本文在综述此前库车盆地构造、蒸发岩、盐类矿物学、地球化学与盐湖沉积等研究基础上,建立了新的库车盆地古盐湖构造- 沉积演变、成钾模式;提出了4个钾盐成矿区带,即北部克拉苏成矿带、中部秋里塔克成矿带、南部沙雅构造沉降成矿带以及东部阳霞凹地成钾区,这些关键认识为库车盆地的钾盐勘查提供了重要的理论和科学依据。     

A Late Quaternary lake record from the Qilian Mountains (NW China): lake level and salinity changes inferred from sediment properties and ostracod assemblages

Two sediment cores (length 13.94 and 12.93 m) have been drilled from the small alpine Lake Luanhaizi in the eastern central Qilian Mountains and correlated by means of magnetic susceptibility (MS). This paper focuses on the lithology and chronology of the longer core, on the results of loss on ignition (LOI), element concentration, thermomagnetic as well as magnetic hysteresis loop measurements, and on the ostracod record.The recovered sediments represent three types of depositional environment: a shallow intermittent lake, a deeper permanent lake and a true playa lake. Three stages of a higher lake level and permanence of the water body are reconstructed. The lowermost stage of a permanent lake and inferred favourable environmental conditions occurred probably about 45 ¹⁴C ka BP. The second stage of a deeper permanent lake occurred either shortly before or, more likely, following the LGM. Most favourable environmental conditions and highest water levels were reconstructed for the uppermost stage comprising the Holocene. Considering the lake record, glaciers have not reached the lake site at 3200 m altitude during the LGM, providing further evidence against a large ice sheet on the Tibetan Plateau.     

A paleolimnological record of anthropogenic disturbances at Holmes Lake,Adirondack Mountains,New York

Holmes Lake, Adirondack Mountains, New York, is a clear-water acidic lake that was treated with lime in 1983 to permit stocking of trout. Diatom assemblages in dated sediments reflect three anthropogenic modifications of the lake ecosystem: 1) assemblages from the mid- and late 1800's are associated with historical and sedimentary records of forest clearance, and indicate slightly increased pH; 2) acidobiontic species increase in sediments from the mid-1900's, a period of local reforestation and regionally increasing anthropogenic acid loading; 3) liming caused large increases of circumneutral periphytic species in the first growing season, and decreases of acidobiontic species by the second.     

Heavy metal research in lacustrine sediment： a review

Heavy metals are released into environment from a wide range of natural and anthropogenic sources. Aquatic ecosystems are normally at the receiving end and in many cases, with lakes as intermediaries. Lacustrine sediments are important sinks for heavy metals and play a significant role in enrichment and remobilization of heavy metals in aquatic systems. Therefore, characteristics of heavy metal in lacustrine sediments become one of the important issues in environmental sciences. Progress in heavy metal research of lake sediments since late 1980s is reviewed comprehensively in this paper from over 100. The Highlights are placed on the establishment of aquatic sediment quality guidelines, references chemical speciation of heavy metals, heavy metal transport mechanisms in lakes, and high-resolution study of lake borehole cores. Meanwhile, suggestions for heavy metal research in lacustrine sediment in the future are proposed, including such issues as using integrated approaches to assess aquatic ecosystem, modem lake dynamic process, high-resolution evolutionary sequence and spatial differentiation of environments and international lake database, which should be referential to the promotion of research on heavy metal in aquatic system.