亚洲中部干旱区的湖泊

采用系统论的观点,对亚洲中部的干旱区湖泊（包括咸海、巴尔喀什湖、博斯腾湖、艾比湖、玛纳斯湖、艾丁湖与罗布泊等）的水分循环与其他物质循环进行综合研究,其结果不仅丰富了生态循环的理论,而且深刻地揭示了干旱区湖泊与湿润区湖泊截然不同的特征;表现出水分循环的独特性、形态测量学的复杂性、风生湖流的奇特性与泥沙运行的规律性以及内陆湖水化学特征和别具一格的水生态循环系统等。干旱区湖泊作为陆地水圈的组成部分,他是一个完整的生态系统。他由湖泊中的生物和水两大亚系统组成,相互作用而又相互联系。尽管大陆性气候严酷和强烈,风生湖流强劲（有时还多亏他的作用）,蒸发量大,但内陆湖能生存数千年,即在现代时间尺度上是无IL尽的。     

山岳冰川的能量分类

应用热力学原理,对冰川低温热力学系统在物态变化中的能量转换,进行宏观分析和计算,用“能量”作量度,用“冰川比内能”。为指标,对山岳冰川进行分类。对世界上34条山岳冰川,以u值100000J为分界,将其划分为高能量和低能量2大类以及相应的6个亚类。同时,讨论了类型特征、界限确定及分类意义等问题。     

洞庭湖平原不同稻田生境越冬蜘蛛群落多样性研究

洞庭湖平原越冬稻田蜘蛛共有８科１６属２１种,其中拟水狼蛛和食虫沟瘤蛛为优势种。异质性大的越冬稻田及田埂蜘蛛群落的多样性指数、丰富度和个体总数均大于异质性小的越冬稻田和三光田埂,越冬稻田蜘蛛群落的多样性指数大小主要由群落物种丰富度和个体总数决定,与均匀度大小无关。     

蠡湖湖滨湿地景观生态格局分析及适宜性评价研究

湖滨湿地是陆域生态系统和湖泊水域生态系统之间的过渡带,在保护湖泊生态系统稳定和生物多样性等方面发挥着重要作用。运用遥感技术对无锡蠡湖湖滨湿地生态修复前后景观生态格局及演变进行分析,从湖滨湿地景观优美性、自然性、稳定性以及服务性4个层面,对蠡湖湖滨湿地景观适宜性进行评价研究,探讨影响湖滨湿地生态系统退化和景观重建的原因,从而为开展湖滨湿地生态修复和景观重建提供理论依据。     

Partitioning characteristics of PAHs between sediment and water in a shallow lake

Goal, Scope and Background

Distribution of hydrophobic organic contaminants in abiotic compartments is essential for describing their transfer and fate in aquatic ecosystems. Taihu Lake is the third largest freshwater lake in China. Water quality of Taihu Lake has deteriorated greatly during the last decades and has threatened the water supply. The aim of the present study was to investigate the partitioning of polycyclic aromatic hydrocarbons (PAHs) among overlying water, suspended particulate matter (SPM), sediments, and pore water in Meiliang Bay, Taihu Lake and to provide useful information for the ecological engineering in this area.

Materials and Methods

Overlying water and surface sediment were sampled from six sites in Meiliang Bay, Taihu Lake, China. Within 72 h of sampling, sediments were centrifuged to obtain the pore water. Overlying water samples were filtered to separate dissolved and SPM samples. After extraction, samples were purified following a clean-up procedure. PAH fraction was obtained by elution with a mixture of hexane: DCM (7:3, V/V) and analyzed by GC/MS.

Results

PAHs concentrations in overlying water varied from 37.5 ng/L to 183.5 ng/L. Concentrations of PAHs in pore water were higher than those in overlying water. The total concentrations of 16 priority PAHs in sediments ranged from 2091.8 ng/g-dw to 4094.4 ng/g-dw. PAHs concentrations on SPM were decreased with suspended solid concentrations (SSC). Total PAHs concentrations on SPM varied in the range of 3369.6 ng/g-dw to 7531.1 ng/g-dw. The partition coefficients between sediment and overlying water (log K _oc) for PAHs with log K _ow<5 were positively correlated with their octanol-water partition coefficients (log K _ow) (n=39, r=0.79, p<0.0001). Partition coefficients between sediment and pore water (log K _oc′) for all PAHs were also significantly correlated with their log K _ow values (n=48, r=0.82, p<0.0001).

Discussion

In general, PAHs derived from combustion sources tend to bind strongly to soot particles in natural sediment. Consequentially, K _oc values observed in the natural environment could be orders of magnitude higher than those predicted by linear correlation relationships under laboratory conditions. In the present study, the ratio of log K _oc values to log K _ow values falls consistently above 1, indicating that the sediment soot carbon in the bay was more attractive for PAHs than n-octanol. The log K _oc′ was also higher than that predicted under laboratory conditions, suggesting that the measured pore water PAH concentrations were lower than those predicted. That is to say, not all the sediment PAHs can be available to partition rapidly into sediment pore waters. A variation in soot content is a possible reason. Furthermore, concentrations of PAHs on SPM were higher than those in sediments. The compositions of PAHs on SPM and in sediments were similar, indicating the importance of re-suspension process of sediments in the partitioning process of the shallow lake.

Conclusions

The results indicated the equilibrium partitioning model could be used to predict PAHs distribution in various phases of a shallow lake in the stagnation period, but re-suspension processes should be considered to modify the relationship between log K _ocs and log K _ows.

Recommendations and Perspectives

Concentration, particle size and composition of resuspended particles could affect the relationship between log K _ocs and log K _ows. Further work should be done under field conditions, especially where a steady thermodynamic equilibrium state could be assumed.

     

Soil morphological control on saline and freshwater lake hydrogeochemistry in the Pantanal of Nhecolândia, Brazil

Joint pedological, geochemical, hydrological and geophysical investigations were performed to study the coexistence of saline and freshwater lakes in close proximity and similar climatic conditions in the Nhecolândia region, Pantanal wetlands in Brazil. The saline lakes are concentrically surrounded by green sandy loam horizons, which cause differential hydrological regimes.Mg-calcite, K-silicates, and amorphous silica precipitate in the soil cover, whereas Mg-silicates and more soluble Na-carbonates are concentrated in the topsoil along the shore of the saline lake. In saline solutions, some minor elements (As, Se) reach values above the water quality recommendations, whereas others are controlled and incorporated in solid phases (Ba, Sr). Locally, the destruction of the sandy loam horizons generates very acidic soil solution (pH ~ 3.5) through a process not yet understood. The soil distributions indicate that some freshwater lakes are former saline lakes. They are invaded by freshwater after destruction of the sandy loam green horizons, then the freshwater becomes enriched in K⁺, SO₄²⁻, Fe, Al, and a stream of minor and trace elements. The formation of these green sandy loam horizons in the saline environment and their destruction in the non-saline one emphasizes the dynamic nature of this environment.     

青山湖流域不同地表覆盖降雨径流中氮磷流失过程研究

在浙江省青山湖流域进行了不同地表覆盖类型野外模拟降雨实验,通过设定不同的坡度和降雨强度,综合分析流域内4种地表覆盖对降雨径流中氮磷流失的减少效果,结果表明：在相同雨强情况下,坡地径流中总氮浓度和氨氮浓度由高到低顺序均为：人工草地、次生林、荒草坡、竹林地。其中,总氮浓度曲线在各地表趋势均保持稳定,降雨强度的增大不影响4种覆盖度的顺序结果,但是人工草地与其他3种类型之间的浓度差值会随着雨强的增大而增大。在相同雨强情况下,坡地径流中总磷浓度白高到低顺序依次为：人工草地、次生林、荒草坡、竹林地。径流中速效磷浓度过程趋势与总磷浓度非常类似,而且随着雨强增大,速效磷占总磷比例也相应提高。     

青山湖流域不同地表覆盖降雨径流中氮磷流失过程研究

在浙江省青山湖流域进行了不同地表覆盖类型野外模拟降雨实验,通过设定不同的坡度和降雨强度,综合分析流域内4种地表覆盖对降雨径流中氮磷流失的减少效果,结果表明:在相同雨强情况下,坡地径流中总氮浓度和氨氮浓度由高到低顺序均为:人工草地、次生林、荒草坡、竹林地。其中,总氮浓度曲线在各地表趋势均保持稳定,降雨强度的增大不影响4种覆盖度的顺序结果,但是人工草地与其他3种类型之间的浓度差值会随着雨强的增大而增大。在相同雨强情况下,坡地径流中总磷浓度由高到低顺序依次为:人工草地、次生林、荒草坡、竹林地。径流中速效磷浓度过程趋势与总磷浓度非常类似,而且随着雨强增大,速效磷占总磷比例也相应提高。     

丽江拉市海国际重要湿地生态修复方案探究

拉市海国际重要湿地是我国重要的候鸟越冬栖息地之一,针对其整体环境整治问题,地方政府和管理部门做了大量工作,取得了较好成效,但还存在退化沼泽湿地急需修复、退养鱼塘急需生态修复、入湖河道急需治理等问题,基于此,提出退化沼泽湿地、退塘还湿、入湖河段生态修复以及破碎化湖滨带治理、外来物种防控等生态修复方案。通过湿地生态修复,湿地整体生态环境得到改善,候鸟栖息地、食源地得到修复,湿地植被和生物多样性明显增加,湿地景观得到优化,湿地生态服务功能有所提高。     

西湖风景区水生植物园林应用研究

通过对西湖风景区内水生植物园林应用情况的大量调查,得到应用种类、分布与应用频率及相应种类的生长发育规律等与水生植物园林应用密切相关的几个要素,并据此对其作了较为全面的分析,将为以后更加科学合理的应用提供良好依据.