太湖水质及其保护

Lake Taihu, the third largest fresh water lake in China, with a surface area of 2 338 km², is located in the Changjiang River Delta, the most advanced economic zone in China. During the last two decades, the rapid economic development of local agriculture and industry both in the urban and rural areas of the region has made great advances. Great quantieis of pollutants have been discharged into the lake, its nutrient content has increased continuously, and phytoplankton blooms have occurred in some areas. Water quality protection in Lake Taihu is very important because of its close relation with economical development and people''s daily life. It is urgent to have comprehensive pollution control in Lake Taihu. Based on water quality monitoring data in Lake Taihu from 1987 to 1994, the dynamic variations of water quality and eutrophication trends have been analyzed, showing obvious spatial and temporal variations. The main water quality factors were compared with the standard for drinking water and indicate considerable change with the seasons. Some basic strategies to protect water quality and prevent eutrophication are discussed.     

太湖水污染控制的目标及设想

According to the social and natural conditions of Taihu Lake Basin, the planning objectives and some ideas for water pollution prevention in Taihu Lake and its surrounding river-lake system are proposed.     

在藻型富营养湖泊中恢复大型水生植物净化水质的物理生态工程——以中国太湖五里湖为例

In the barren lake, algae-type eutrophication lake, fifteen aquatic vascular plants were introduced and vegetated in our enclosures of physical-ecological engineering. The area of each enclosure is 200 m², with length of 40m, width of 5m and depth of 1.8m. From 1995 to 1997, we had successfully vegetated 15 communities with the propagation techniques of pot-culture and sturdy seedling. The communities included floating, leave-floating and submerged macrophytes, such as Altemanthera phyiloxeroides, Eichhomia crassipes, Trapa maximowiczii, Nymphoides peltata, Potamogeton maackianus, P. crispus, Myriophyllum spicatum, Hydrilla verticillata, Elodea nuttallii, etc. These aquatic macrophytes not only adapted themselves to the environment but also purified the lake water.     

太湖—中国东部平原的一个大型浅水湖泊

The outline of Taihu Lake Basin, including the geographical and hydrometeorological characteristics, its main functions and resource-environmental state and problems facing in Taihu Lake were introduced.     

改善中国太湖水生态环境的新对策—“如何解决太湖流域水质型缺水和环境自然资源退化问题？”

Taihu Lake is one of the famous five great freshwater lakes in China. Taihu Lxike Basin (TLB) is a densely populated and economic developed area in China. The surface water quality in TLB was deteriorated from I-Ⅱ grade in the history to IV-V grade at present. To develop a series of technology of most cost-effective and achievable for improving environment in a local water area of most sensitive for society and improving water quality for more and more areas step by step is the key point of the new strategy. Except the measures for reducing the industrial and domestic pollution load to the lake, some research topics are suggested to be emphasized.     

太湖风生流数值模式及其对总磷分布的影响

A new up-winding finite element numerical model, which is two-dimensional and suitable for modeling lake current and the distribution of total phosphorus(TP) in shallow lakes, is derived. Moreover, it is used in the study of wind-driven current in Taihu Lake, and the impact of lake current field on the distribution of TP is also discussed.     

太湖环棱螺对两种常见沉水植物生长的影响

环棱螺(Bellamya sp.)是太湖常见的一类软体动物.本研究通过室内实验,探讨环棱螺对轮叶黑藻(Hydrilla verticillata Royle)和伊乐藻(Elodea nuttalli ST John)生长的影响及水体营养盐含量的变化.结果表明,三种处理情况下,单位质量伊乐藻增加的数量分别为:H组0.475 g,L组0.106 g,C组0.021 g,单位质量轮叶黑藻增加的数量分别为:H组0.704 g,L组0.663 g,C组0.478 g.从实验前后两种沉水植物的长度和分蘖数变化来看,H组最高,L组与C组分别次之,所以不论生物量、长度还是分蘖数的变化量,与环棱螺共存的伊乐藻和轮叶黑藻的变化都高于对照组中两种沉水植物的变化.环棱螺新陈代谢促进水体中溶解态氮磷含量增加,三种情况下水生植物的初级生产力都相当,由此可推测环棱螺通过新陈代谢,一定程度上促进了两种沉水植物的生长.     

夏季短期调水对太湖贡湖湾湖区水质及藻类的影响

贡湖湾作为"引江济太"工程长江来水进入太湖的第一站,湖湾水体生态环境的变化是对调水工程净水效果的最好响应,因此本文针对贡湖湾一次夏季短期调水展开调查研究,分别取2013年7月24日(调水前)和2013年8月18日(短期调水后)两次监测水样的水体理化指标和浮游藻类群落数据进行了对比分析,并对浮游藻类群落与环境因子做了相关性分析.结果表明:受来水影响,短期调水后监测区水体的p H略有下降,溶解氧、浊度、硝态氮、总氮、总磷以及高锰酸盐指数等水体理化指标浓度均较调水前有所升高;其中受调水影响最为显著的区域为望虞河的入湖口区、湾心区.两次监测调水前后湖区水体优势藻种属未发生变化,仍以微囊藻为主,但蓝藻种属比例有所下降,绿藻和硅藻等种属比例则有所上升.望虞河入湖口区和贡湖湾湾心区的Shannon-Wiener多样性指数和Pielou均匀度指数受调水的影响升高.同时,浮游藻类群落结构与受水水体理化参数的冗余分析结果表明,此次监测的短期调水后,太湖贡湖湾监测湖区水体p H、溶解氧、硝态氮、总氮、总磷、高锰酸盐指数等环境因子与浮游藻类的群落分布呈显著相关,是影响受水水体中藻类群落的主要环境因子.     

太湖蓝藻碎屑对水质及附着藻和水丝蚓生物量的影响

富营养化是现今各国面临的主要水环境问题,其中蓝藻水华暴发是全球富营养化水体最常见的现象之一.蓝藻水华将产生大量的蓝藻碎屑,其对水质及生物的影响还尚不清楚.本研究通过向中宇宙系统添加微囊藻碎屑,分析其对水体不同形态营养盐及水生生物生物量的影响.结果表明:微囊藻碎屑加入后,水体不同形态的营养盐浓度均在短期内迅速增加,其中水体总氮和总磷平均浓度最高分别达到3.86和0.36 mg/L;浮游植物生物量(用叶绿素a表示)在前9天随营养盐浓度的升高而增加,随后逐渐下降至实验初始水平.此外,附着藻类生物量在微囊藻碎屑加入后呈逐渐下降趋势,这可能与浮游植物快速增殖引起的水体透明度下降有关.微囊藻碎屑加入后,水丝蚓生物量随微囊藻碎屑的分解持续增长,在第20天达到生物量最大值.本研究通过模拟太湖梅梁湾生态系统,探讨微囊藻碎屑对水质及水生生物生物量的影响,结果有助于进一步了解蓝藻水华对水生态系统影响的途径及机理,为富营养化湖泊管理提供理论依据.     

尼罗河三角洲早—中全新世气候—环境变化对早期农业发展的影响

对尼罗河三角洲平原东北部一个古埃及文化遗址(Kom El-Khilgan)1.5 m长的沉积物剖面KH1开展14C测年、沉积物粒度和孢粉分析.根据岩性、粒度和测年等结果综合判定:剖面150~100 cm地层为早全新世河流相沉积;100~27 cm地层为早、中全新世(8000—4000 cal a BP)三角洲冲积平原沉积,其中涵盖了古埃及前王朝至古王国时期(6500—4131cal a BP)的人类活动信息;27~0 cm为现代表土层.孢粉分析结果反映了在距今8000~4000 a期间:1)研究区气候由湿润过渡为温和,最后趋于干旱;2)随着气候变干,尼罗河上游水文变化对三角洲环境影响减小,研究区由沼泽湿地逐渐过渡为干草甸环境,更多的土地可以被人类利用;3)常被用来指示农业活动的35μm禾本科、陶器碎片和炭屑的出现并逐渐增加,表明该遗址附近的人类农业活动始于距今6500 a左右,并持续至距今4000 a前后.上述证据表明尼罗河三角洲全新世早—中期湿润向干旱过渡的气候驱动了人类农业活动的开展.本研究为进一步探讨尼罗河三角洲古文明对环境适应性研究提供了科学依据.     

净化湖泊饮用水源的物理-生态工程实验研究

我国许多历史上水质优良的湖泊水源区已污染严重污染,净化饮用水源刻不容缓。本文介绍了自１９９１年以来太源进行的物理－生态工程的部分研究成果。着重介绍在太湖的重富营养湖湾－五里湖无锡中桥自来水厂水源区的静态和抽水动态实验。     

中国太湖五里湖内不同凤眼莲密度圈闭内的沉降率

The dynamic model of physical-biological engineering for purifying water quality in Lake Taihu needs the parameter of sedimentation rate (SR). Especially, it is seldom reported how SR is influenced by interactions between algae and aquatic plant. So 6 enclosures with each area of 5×5 m² were constructed in Wulihu with 2 m depth, a small hypereutrophic bay of Taihu Lake, China. Enclosures, in which the original water quality was the same as that in surrounding lake, were input Eichhomia crassipes at various original densities from 0-6 kg·m^-2 on August 9, 1996. SR had been measured separately at depths of 0.6, 1.2f 1.8 m in each enclosure during 20 days. Main results were as follows:1) SR average in enclosures (17.3g·m^-2 d^-1) was as much as about 1/14 that in the surrounding lake; 2) The deeper was it, the higher rate was it in each enclosure, generally; 3) SR cures versus original densities of Eichhomia crassipes (ODE) in enclosures had the ship of "V" at different depths; SR minimuma were observed in the enclosure with original meso-density of Eichhomia crassipes (EMESO, 4kg·m^-2), the average of SR minimuma was about 8.55 g ·m^-2 d^-1) SR in enclosures with original hypo-density (EHYPO, 0-3kg·m^-2) were mainly negative related with water temperature and light intensity;while those with original hyperdensity (EHYPR, 5-6kg·m^-2) were mainly negative related with transparency (SD) instead.These SR-distribution characteristics may be explained by interactions between dead algae and relics of Eichhomia crassipes.     

Hydrodynamic-phytoplankton model for short-term forecasts of phytoplankton in Lake Taihu, China

Phytoplankton biomass is an important factor for short-term forecasts of algal blooms. Our new hydrodynamic-phytoplankton model is primarily intended for simulating the spatial and temporal distribution of phytoplankton in Lake Taihu within a time frame of 1-5 days. The model combines two modules: a simple phytoplankton kinetics module for growth and loss; and a mass-transport module, which defines phytoplankton transport horizontally with a two dimensional hydrodynamic model. To adapt field data for model input and calibration, we introduce two simplifications: (a) exclusion of some processes related to phytoplankton dynamics like nutrient dynamics, sediment resuspension, mineralization and nitrification, and (b) use of monthly measured data of the nutrient state. Chlorophyll-α concentration, representing phytoplankton biomass, is the only state variable in the model. A sensitivity analysis was carried out to identify the most sensitive parameter set in the phytoplankton kinetics module. The model was calibrated with field data collected in 2008 and validated with additional data obtained in 2009. A comparison of simulated and observed chlorophyll-α concentration for 33 grid cells achieved an accuracy of 78.7%. However, mean percent error and mean absolute percent error were 13.4% and 58.2%, respectively, which implies that further improvement is necessary, e.g. by reducing uncertainty of the model input and by an improved parameter calibration.     

基于"标准化"背角无齿蚌(Anodonta woodiana)对太湖五里湖重金属污染的主动监测

将人工繁育的"标准化"背角无齿蚌(Anodonta woodiana)移殖至太湖五里湖,并以仍养殖在未受污染的中国水产科学研究院淡水渔业研究中心南泉基地的同批蚌作为对照,进行为期9个月的主动监测研究.每3个月回收一次蚌样,应用电感耦合等离子质谱仪(ICP-MS)测定15种重金属(Al、Cr、Mn、Fe、Co、Ni、Cu、Zn、As、Mo、Ag、Cd、Ba、Tl和Pb)的含量.结果表明,南泉基地对照组和五里湖移殖组的蚌样对重金属均产生了明显的生物积累.培养3个月的五里湖移殖组蚌样中As的含量显著高于同期南泉基地对照组,而前者Mn、Fe、Zn和Ba含量显著低于后者;培养6个月的五里湖移殖组蚌样中Al和Pb的含量显著低于同期南泉基地对照组;培养9个月的五里湖移殖组蚌样中Pb含量显著低于同期南泉基地对照组.然而,南泉基地对照组和五里湖移殖组蚌样中重金属(Cr、Cu、As、Cd和Pb)含量均低于我国及国际上的相关标准.培养3、6和9个月的南泉基地对照组及五里湖移殖组蚌样的重金属污染指数分别为1.8、1.8,2.4、2.1和8.3、16.8,均值综合污染指数分别为0.0218、0.0289,0.0337、0.0218和0.0560、0.0732,属于正常背景水平,并且两水体蚌样的重金属污染指数和均值综合污染指数无显著差异,提示五里湖和南泉基地均未受到明显的重金属污染.     

太湖微囊藻的生长动力学

Following the development of local industries, agriculture and the increase of living standard of people, Lake Taihu is in the meso-eutrophication stage. The main eutrophication part in this lake is the Meiling Bay. The dominant phytoplankton species are Microcystis, Anabena, Melosira, Cyclotella and Cryptomonas. In summer, Microcystis spp. occupys 85% of algae biomass and form the water bloom. This causes the trouble for the people lived around the lake, especially for the drinking water of Wuxi City.The Microcystis intrinsic rate was high, the Max. growth rate 1.27. Besides Microcystis own characteristics, its growth depended on irradiation, temperature and nutrients, especially the phosphorus. This paper also discussed the possibility of biomanipulation for restoration of lake ecology and the control strategy of lake eutrophication.     

微生物对太湖微囊藻的好氧降解研究

通过模拟实验研究了微生物对微囊藻残体的降解作用。水体内悬浮质和各主要形态磷浓度的变化结果表明：微囊藻的好氧分解符合一级动力学,其乳浮质和颗粒性磷的浓度呈指数关系递减,降解速度分别为０．２２７／ｄ和０．０８８／ｄ。经３２ｄ降解后,水体内的总溶解磷和可达总磷的５３％,而ＴＤＰ的主要成分为ＰＯ＾３－Ｒ。     

中国太湖梅梁湾湖流及散度场：水—气耦合模式

Research is conducted on the distribution features of flow and divergence fields under the stress of ununiform and unsteady wind at Meiliang Bay on Lake Taihu by using a 3D atmospheric boundary layer model and a 2D hydrodynamic model for the area of the lake. Some meaningful results were achieved.     

太湖梅梁湾湖区悬浮物动态沉降特征的野外观测

沉降运动是悬浮物主要运动形式之一,是影响营养盐内源释放的主要运动过程,研究悬浮物沉降速度对湖泊富营养化的研究具有重要意义.为了解浅水湖泊悬浮物的沉降特征,以太湖梅梁湾为例,采用声学多普勒流速仪,光学后向散射浊度仪以及风速风向仪在梅梁湾进行了连续9 d的野外观测.采用扩散沉降平衡的方法计算小风速情况下悬浮物的沉降速度,并对沉降速度与垂向流速、风速、悬浮物浓度的关系进行分析.结果表明悬浮物平均沉降速度为0.0785 mm/s,表层垂向流速和悬浮物浓度对悬浮物沉降速度变化起主要作用;而在底层,风速、垂向流速、悬浮物浓度都对悬浮物运动有重要影响,具体表现为风速1.5 m/s时,垂向流速紊动增大,悬浮物因起悬而浓度较大,并且沉降速度波动较大;风速1.5 m/s时,垂向流速基本向下且流速较小,沉降速度也较小.本文揭示了大型浅水湖泊悬浮物的动态沉降特征,为今后太湖污染物的输移、水环境数学模型和湖泊富营养化的深入研究奠定了必要的基础.     

太湖不同湖湾中铜锈环棱螺(Bellamya aeruginosa)的氮稳定同位素特征

进入湖泊中不同氮源氮稳定同位素值(δ15N)的差异和生物对氮稳定同位素的记忆作用,可以反映流域人类活动输入的污染物对生态系统的影响程度.本文调查了太湖4个湖湾(梅梁湾、贡湖湾、竺山湾和东太湖)中铜锈环棱螺(Bel-lamya aeruginosa)的δ15N值,结果表明环棱螺δ15N值的变幅为6.9‰～18.1‰,平均值为11.2‰,不同湖湾中环棱螺δ15N值差异极显著,从高到低依次为梅梁湾(17.7‰)、贡湖湾(13.2‰)、东太湖(10.2‰)和竺山湾(7.8‰).分析认为,梅梁湾和贡湖湾接纳较多的人类活动产生的污染物,其周边城市如无锡、常州等地的污水处理效率有待提高;竺山湾水体氮素主要来自于农业面源污染,需降低农田化肥的使用量.