Holocene lake deposits of Bosten Lake, southern Xinjiang, China

A 9.25-m-long sediment core from Bosten Lake,Xinjiang, provides detailed information about changes in the water budget and biological acticity over the last 8400 cal-endar years. The chronology is constructed from six AMS radiocarbon dates on the terrestrial plant remains. Based onanalyses of TOC, CO3, detrital compounds and biogenic SiO2,lake level fluctuations and periods of remarkably-negative water budget appeared at 8.4-8.2 cal ka, 7.38-7.25 cal ka,5.7-5.5 cal ka, 3.7-3.4 cal ka and 3.3-2.9 cal ka, respec-tively. As they are in-phase with low lake levels at Sumxl Co and Bangong Co in western Tibet Plateau and with paleo-lakes in Inner Mongolia, a climate-induced change to some-what drier and warmer conditions is inferred. A further drop in lake level after 1320 AD of about 200 yr duration may heattributed to a negative water balance prior to the main phase of the Little Ice Age. Deep and stable lake phases of 1500 yr and 1800 yr duration at 7.2-5.7 cal ka and 5.5-3.7cal ka coincide with maximum moisture during the Holocene Megathermai in China. The long term trend towards aridity since about 4.3 cal ka can dearly be recognised. The reduced water budget of Bosten Lake from 640-1200 AD may be attributed to local effects.     

Temperature variations on the Tibetan Plateau over the last two millennia

The paleoclimate data recovered from ice cores,tree rings and lake sediments indicate regional features of cfimatic change on the Tibeta n Plateau (TP) during the last 2000 years. The composite temperature reconstructions in-dicate that several main climatic episodes, such as the “LittleIce Age“ between 1400 and 1900, the “Medieval Warm Pe-riod“ in 1150-1400, a less warm period in 800-1100, and an earlier cold period between the 3rd and 5th centuries,occurred in the TP. In addition, temperature varied from region to region. The period from AD 800 to 1100, which waswarm in northeastern TP, was contemporaneous with cool-ing in the western and southern TP. The southern TP ex-perienced warming between 1150 and 1400. For western TP,the δ^18O records of the Guliya ice core indicate that the pe-Hod 1250-1500 witnessed a clear warming. Large-scaletrends in the temperature history from northeastern TP aremore similar to those in eastern China than are the trendsfrom the Guliya ice cap far to the west and southern TP. The most prominent similarities between the temperature varia-tions of the TP and eastern China are such cold phases as 1100-1150, 1500-1550, 1650-1700 and 1800-1850, andthe latter three cold events match with three widespreadg lacial advances which occurred on the TP during the Little Ice A2e.     

波浪加载下海底土质特性变化的研究

通过不同的制样方法，在水槽中模拟了多种海底在波浪作用下的变化行为。试验发现，加压排水固结的砂质粉土海底在波浪作用下较稳定；加压不产生排水而固结的砂质粉土海底易受波浪的冲刷；自然条件和轻微振动的砂质粉土海底最易受到波浪的扰动破坏，形成塌陷凹坑。粘粒含量较高的粉质粘土对波浪的反映不敏感；下卧软土层土体在上覆压力下的变形量与含水量关系密切，含水量越高，变形越大。试验结果证明，波浪会引起沉积物性质发生改变，也是引起海底形态变化的主要原因。     

水体及沉积物中碱性磷酸酶的研究进展

阐明了碱性磷酸酶在水体和沉积物生态系统中的作用，重点综述我国海湾和淡水湖泊水体及沉积物中碱性磷酸酶的研究状况。     

沉积物对汽油机碳氢排放物形成的预测与实验研究

建立了汽油机燃烧室沉积物处未燃碳氢生成和氧化模型，测量了有、无燃烧室沉积物时发动机排气中的碳氢摩尔浓度．实验结果表明：沉积物的存在将增加发动机碳氢排放量，在本实验用机及实验条件下，沉积物将使发动机排气中的碳氢摩尔浓度增加２０％～３０％．计算结果表明：本模型能较好地预测出沉积物形成的排气碳氢摩尔浓度     

Hg(Ⅱ)在泉州湾滩涂沉积物上的吸附

研究了Hg（Ⅱ）在泉州湾滩涂沉积物上的吸附行为，并在此基础上初步探讨了其吸附机理．主要讨论了pH和温度对吸附作用的影响，并绘制了吸附等温线．实验结果表明，常温下Hg（Ⅱ）在泉州湾滩涂沉积物上的吸附平衡时间约需3h，吸附作用随pH的升高而增强，受温度的影响变化不大．其吸附行为既符合Freundlich型吸附等温式，又符合Langumuir型吸附等温式，说明其吸附机理非常复杂．     

Response of downstream sediment to water resource development in mainstream of the Lancang River

The impact of hydropower cascades of the Lancang River on downstream sedimentation has become one of the key problems in the research of the transboundary water resource development and its possible environmental effects. In this paper, the newest sediment data series spanning 17 years （1987-2003） at Yunjinghong hydrometric station and Chiang Saen hydrometric station, in northern Thailand, are analyzed to reveal these effects. Monthly mean sediment concentration data of the two stations are compared in-phase and yearly series are analyzed by the method of correlation and regression analysis and causality test. The analysis result shows that, though both of them are located at lower reaches of Manwan and Dachaoshan hydropower stations which are already constructed and in use, the sediment responses of the two stations are different under the regulation of the hydropower stations Annual series at Yunjinghong station are positively correlated but do not match well with those at Chiang Saen station. In addition, the results of Granger causality test on the time series also suggest that the series of maximum monthly mean sediment concentration of the Yunjinghong station each year may give cause for the ones of Chiang Saen station, while the series of minimum monthly mean sediment concentration each year and annual mean sediment concentration of Yunjinghong do not evidently give cause for the ones of the other station. Undoubtedly, this discovery will provide new evidences to assess the impacts of cascades construction in mainstream of the Lancang River on the variation of downstream sediment and its transboundary effects.     

富营养化湖泊中沉积物原位治理技术进展

回顾了各种化学、物理和生物的原位治理技术,简要介绍了一种新的生物膜合成载体.在户外实验中,富营养的沉积物促进了毒藻的生长,而新合成的生物膜载体的布设可以阻碍藻类的生长.当应用这种新的合成载体来改善富营养化湖泊水质时,沉积物中P的形态也向有利于水质改善的方向变化.     

底质粒度信息的空问分异与代表性：以杭州湾舟山岛-金山卫断面为例

对杭州湾舟山岛-金山卫断面沉积物柱状样进行了高密度采样，并用激光粒度仪进行了粒度分析．结果显示，在不同站位沉积物平均粒径具有不同的垂向分布．由于该断面所在区域海底活动性强，短时间尺度的活动层厚度的量级远高于长时间尺度的净沉积速率的量级，平均粒径的垂向分布特征更多地反映了同一沉积环境中形成的不同类型沉积记录，很难代表沉积环境的长时间尺度演化．粉沙为主和沉积物粒径的垂向平均值随着厚度的增加而呈现收敛趋势的底质粒度特征，说明物源因素控制着研究区总体的沉积物分布规律，而水动力因素造成了一定程度的沉积分异．沉积物的垂向分异使表层底质粒径的断面分布不同于活动层内垂向平均底质粒径的断面分布．对于强潮、粉沙环境的沉积物输运模拟而言，如果涉及的时间尺度较大，则采用活动层的平均值作为模型的粒度参数较为合适．     

应用生物效应数据库法建立沉积物重金属质量基准的初步研究——以渤海锦州湾海洋沉积物为例

应用当前国际上最被广泛接受的生物效应数据库法尝试建立了渤海锦州湾初步的沉积物重金属(Cu、Pb、Zn、Hg)质量基准，同时从三个角度对所得的基准进行了检验，检验结果表明，计算所得的基准与其定义的生物效应基本一致．