太湖短吻银鱼的胚胎发育

椭圆卵囊藻培养轮虫时,轮虫平均产卵量均低于４．０个,随着食物浓度增加,后代混交雌体百分率降至１２．５０％．投喂蛋白核小球藻,轮虫的平均产卵量从６．００增加到１１．４０个,后代混交雌体百分率降至４．５８％．小球藻和卵囊藻混合培养轮虫,轮虫平均产卵量少于５．００个,后代个体混交百分率下降．当小球藻浓度增加到８．０＊１０（６）ｃｅｌｌｓ／ｍｌ时,平均产卵量下降至８．３３个,混交百分率也明显升高。     

道观河水库大银鱼移殖生物学效应──3.繁殖行为

根据对道观河水库移殖的两个世代大银鱼的繁殖群体进行跟踪观察,认为1)大银鱼的繁殖与气候突变,气温骤降有关;2)大银鱼繁殖期间性比的变化与雌雄个体差异及行为约变化有关;3)同一水体的大银鱼繁殖群体具有时空异质性．     

高背鲫移殖的研究

总结了在花园湖渔业开发技术中云南滇池高背鲫移殖的研究工作。结果表明,移殖后很快形成稳定的种群,鲫鱼总产从1986年的16.12×10~4kg提高到1989年的33.3×10~4kg,经济效益、社会效益和生态效益均较显著。     

太湖大银鱼生长特性的研究

本文根据太湖大银鱼(Protosalanx hyalocranius Abbott)周年生物学实测资料,并应用Von Bertalanffy生长方程进行计算,对大银鱼在太湖的生长规律及特点进行分析探讨,结果表明:1.体全长与体重呈幂函数关系:W=3.981×10~(-6)L~(2.9359);2.Von Bertalanffy生长方程的各项参数值为:L_∞=219.86(mm),W_∞=28.56(g),K=0.1469,t_0=0.33;3。生长拐点年龄为7、8月龄。     

近太湖新银鱼——银鱼移植新对象

近太湖新银鱼不仅在形态上与太湖新银鱼很相似,而且它们的个体大小、生长速度、食性等方面也十分相近。近几年在湖北地区的湖泊、水库相继发现了近太湖新银鱼,并在湖北省广水市徐家河水库成为优势种类,形成了较大生产规模。从目前研究的结果来看,近太湖新银鱼也是适宜我国湖泊、水库移植的银鱼种类。     

基于COI基因序列的太湖新银鱼遗传多样性

利用线粒体细胞色素C氧化酶I(COI)分子标记分析长江中下游太湖新银鱼(Neosalanx taihuensis)8个地理种群132个样本的遗传多样性.该基因630 bp片段的碱基序列共检出8个核苷酸变异位点(变异率1.27%),其中局域性单倍型居多(75%),群体单倍型多样性较高(h=0.576±0.036),而核苷酸多样性较低(π=0.00112±0.00204).不同地理种群遗传多样性差异显著:有人工移植历史种群遗传多样性较高、隔离度较高的种群遗传多样性较低,但大部分的遗传变异来自于种群内(54.83%),反映出地理隔离和人为干扰对太湖新银鱼遗传格局影响显著.研究表明COI基因适于银鱼科鱼类物种鉴别和系统发育研究,同时可为同种种群间遗传关系分析提供一定的信息.     

白龟山水库银鱼移植试验

1987年一次性向白龟山水库投放太湖新银鱼有效受精卵21×10~4粒,后形成强大种群生产力,1991～1993年累计生产银鱼190t,创经济效益500余万人民币。太湖新银鱼具有生命周期不长、食物链较短、适应环境能力较强、容易捕捞等优点,是“填补”移植驯化的理想对象。白龟山水库生态系中鱼类区系组成不够饱和,存有空闲小生境,饵料竞争比较缓和,敌害压力较小,是移植驯化银鱼的适宜水体。白龟山水库银鱼食性组成中以桡足类和枝角类为主;分布遍及全库,尤以上、中游水草区为最多。1991年全库银鱼相对资源蕴藏量为108920kg,即1.56×10~(?)尾。1991年约有29.5％的浮游动物被银鱼利用转化成为银鱼产品,生物学效益较高。综合考虑银鱼的繁殖和生长,在现有捕捞强度下,捕捞生产宜安排在11月～翌年2月为宜。     

太湖水动力学三维数值试验研究——4.保守物质输移扩散

物质输移扩散规律是大型浅水湖泊水质变化机理研究的重要内容,对湖泊水环境的管理具有重要的现实意义,本文在太湖湖流三维模型研究成果的基础上,创建了太湖保守物质输移扩散三维数值模型,并用之模拟了1997年冬季1～2月太湖总磷含量的变化,计算结果表明,模型计算值与观测值吻合,本文所建的保守物质输移扩散模型,可用于冬季太湖营养盐含量时空变化的计算。     

太湖新银鱼、鲚鱼的食性比较及相互影响分析

在太湖,通过对263个太湖新银鱼和鲚鱼胃含物样本的食物组成分析和比较,研究了两种鱼类间的食物关系;并结合太湖历年鱼类渔获量资料,对渔获量变化间可能存在的相互影响进行了偏相关分析.结果表明:太湖新银鱼在4月份的食物中以桡足类为主,占个数的70.11%±10.57%,其次是枝角类,为29.84%±10.62%,轮虫的数量极少,仅占0.05%±0.11%;在4月份1 鲚鱼的食物中以枝角类为主、占79.35%±11.42%,桡足类占19.97%±10.78%,而轮虫和虾的数量很少,分别占0.49%±0.45%和0.20%±0.44%.而在9-10月份0 鲚鱼的食物中,枝角类占89.77%±13.69%,桡足类占7.84%±11.53%,轮虫占2.39%±4.95%;用Pianka提出的公式,计算两种鱼类在4月份5个采样点的饵料重叠系数平均为0.4739±0.2810,没有达到Keast提出的Ojk＞0.7的严重重叠水平;计算5个采样点的相同食物组成比平均为46.42%±20.32%,和饵料重叠系数接近.而偏相关分析表明:两种鱼类数量变化间的相关关系是负向的,且随着鱼类密度的增加,负相关关系的显著水平有不断提高的趋势.如1973-1984年期间的负相关关系远没有达到显著水平(r=-0.2531 p=0.584),而1985-2004年期间的负相关关系接近显著水平(r=-0.4395 P=0.101).分析认为:太湖新银鱼和鲚鱼的食物虽有重叠,但通常情况下食物竞争并不激烈;种群数量变化间的相互影响是负向的,没有达到显著水平.可能仅在两种鱼类密度很高时,激烈地食物竞争才会发生、并主要表现为对哲水蚤和剑水蚤的竞争;且数量间负向的相互影响有加强趋势.     

太湖西部环湖河道污染物输移速率变化特征

阐明污染物出入湖输移速率对于湖泊陆域污染控制具有重要意义.本文研究了太湖西部主要环湖河道总氮（TN）、溶解性总氮（DTN）、总磷（TP）、溶解性总磷（DTP）和高锰酸盐指数（COD_Mn）输移速率变化特征.结果表明环湖河道上述指标净输入速率分别为707.9、727.0、28.8、18.2和700.9 g/s.城东港、百渎港、大浦港和沙塘港4条河道TN、DTN、TP、DTP和COD_Mn输入速率分别占西部河道总输入速率的62.7%、63.6%、67.1%、66.6%和64.8%.太浦河、长兜港和大钱港TN、DTN、TP、DTP和COD_Mn输出速率占总输出的86.5%、86.9%、85.0%、85.3%和80.6%.污染物净输入速率受水情影响,TN和DTN浓度汛前最大,而TP、DTP、COD_Mn浓度汛期增大,汛后分别降低44.2%、48.8%和39.8%.城东港氮、磷输入速率受浓度控制,其他河道各指标输移速率受流量控制.近岸湖体TN浓度与入湖速率呈显著正相关,而离岸湖体TN、TP、COD_Mn浓度对入湖速率的变化响应不明显.     

Seismic modelling study of a subglacial lake

We characterize the seismic response of Lake Vostok, an Antarctic subglacial lake located at nearly 4 km depth below the ice sheet. This study is relevant for the determination of the location and morphology of subglacial lakes. The characterization requires the design of a methodology based on rock physics and numerical modelling of wave propagation. The methodology involves rock-physics models of the shallow layer (firn), the ice sheet and the lake sediments, numerical simulation of synthetic seismograms, ray tracing, τ–p transforms, and AVA analysis, based on the theoretical reflection coefficients. The modelled reflection seismograms show a set of straight events (refractions through the firn and top-ice layer) and the two reflection events associated with the top and bottom of the lake. Theoretical AVA analysis of these reflections indicates that, at near offsets, the PP-wave anomaly is negative for the ice/water interface and constant for the water/sediment interface. This behaviour is shown by AVA analysis of the synthetic data set. This study shows that subglacial lakes can be identified by using seismic methods. Moreover, the methodology provides a tool for designing suitable seismic surveys.     

An event-based stochastic model of phosphorus loading into a lake

In most lakes, phosphorus (P) is the nutrient controlling the trophic state. Thus, for effective control of eutrophication, the uncertainty in P-loading should be encoded as a probability density function (pdf). Specifically, the pdf of P-loading Y from non-point agricultural sources is sought by means of an event-based stochastic model.P-loading events are triggered by precipitation events (X₁, X₂, T), in which X₁ is the rainfall amount, X₂ the duration, and T the interarrival time between events. (X₁, X₂) are dependent random variables, while T is assumed to be exponentially distributed. The precipitation event causes runoff, which carries dissolved P into the lake with a concentration C₁ and sediment yield, Z, which carries fixed or sorbed P into the lake in a fraction C₂ of Z. Seasonal loading of P is calculated by adding random numbers of random variables. The model accounts separately for dissolved P and sorbed P. Explicit expressions are given for the mean and variance of each type of P-loadings. The case study of a sub-watershed of Lake Balaton, Hungary, is used to illustrate the methodology. Precipitation data, empirical rainfall-runoff-sediment yield relationships and a small number of observations of events are used to calibrate the model and estimate the means and variances of loading per event and per season. Then a simulation method is used to estimate complete pdf of these random variables. Use of the model for alternative methods of controlling P-loading is briefly discussed, as well as the economics of control.     

GIS技术在洪湖环境演变研究中的应用

本文运用GIS技术,探索了洪湖环境的近期变化及其机理,以空间的、定量的形式,展示了与修建隔堤、分割湖区、围湖垦殖及水位控制等人为活动因素相联系的湖泊环境变化效应和过程,分析了湖中挺水植物分布的动态变化与趋协。这项工作进一步表明了地理信息系统方法在湖泊环境变化的监测、评价和研究中具有独特的功效和实用价值。     

An investigation into the source of magnetic minerals in some Finnish lake sediments

The source of magnetic minerals in the sediments of five Finnish lakes, which carry a palaeomagnetic record of the geomagnetic field, was found to be primary magnetite in the glacial drift of the catchments. The magnetite is concentrated in the central lake sediments. The ratio of haematite to magnetite was found to decrease in the progression drift-stream bedload-lake sediment. A consistent, temporal decrease of magnetic mineral concentration was found in all the lake sediments studied and is related to maturation of the soils and vegetation surrounding the lakes. This distinctive trend contrasts with that seen in Britain and is discussed in terms of man's influence on landscape development.     

湖泊水情遥感研究进展

湖泊作为最直接的淡水资源之一,在人类的生产、生活各方面都占据至关重要的地位.受到全球气候变化与人类活动的影响,湖泊正在发生急剧变化,因而有必要对其进行快速、准确的时空变化监测,从而为水资源管理与保护、未来气候变化预警提供依据.遥感技术的产生与发展为大范围、实时动态的湖泊变化监测提供了难得的契机,它克服了人类对湖泊实地考察的局限性.本文对现有国内外湖泊水情遥感监测技术与方法进行了综合梳理,主要综述了国内外在湖泊水域范围提取、湖泊水位提取、湖泊水量估算、流域水文过程等方面的遥感研究进展情况,重点总结了该领域近年来提出的新方法和新技术.最后,结合当前遥感技术的发展,对未来遥感在湖泊动态变化监测中的应用潜力和趋势进行了简要论述,并对多源遥感数据融合与云计算平台的结合在地表水体连续变化监测中的应用进行了展望.     

湖泊缓冲带范围划定的初步研究——以太湖为例

本文以我国大型浅水湖泊——太湖为例,通过资料调研、地形勘测、现场调查、研究与分析等手段,开展太湖缓冲带范围划定研究.在文献调研国内外河湖缓冲带研究的基础上,确定太湖缓冲带宽度为2 km不等,其中环湖大堤及湖岸线为缓冲带的下边界,以下边界线向陆地扩展2 km不等为基准,考虑标识物(村落、山体、公路)及区域差异等原则,确定...     

Experimental study on phosphorus release from sediments of shallow lake in wave flume

Influence of wave on sediment resuspension and nutrients release from sediments, collected from Lake Taihu and Lake Chaohu, was studied in flume experiments. Under strong-wave conditions, concentrations of suspended solids (SS), total phosphorus (TP) and dissolved total phosphorus (DTP) in overlying water were increased significantly following the sediments re-suspension. During the experiments on sediments of Lake Taihu and Lake Chaohu, TP concentrations increased 6 times and 3 times, and DTP concentration increased 100% and 70% more than it in presuspension, respectively. Concentration of soluble reactive phosphorus (SRP) of experiment on sediment of Lake Taihu increased 25%. During the massive sediment suspension, the dissolved phosphorus in pore water and much of the phosphorus adsorbed by the sediment particles were released into overlying water. The phenomena in this wave flume experiment are quite similar to the situation observed in situ of Lake Taihu. The critical wave stresses of sediment re-suspension are nearly equal. The change of concentrations of SS, TP, and SRP was the same as that in situ situation. This study showed that concentrations of TP and SRP in lake water could be increased significantly by wave disturbance. Phosphorus release was significantly enhanced by wave disturbance at the beginning of massive sediment re-suspension, but decreased later.     

柴达木盆地早更新世湖相非冰川碎屑纹泥的初步研究

柴达木盆地东部三湖地区早更新世湖相沉积层中,阶段性地发育了具季节性韵律层理的钙质泥岩和泥灰岩。组构、粒度、矿物成分、氧碳同位素及沉积相等研究表明:这是一种成因上与湖水年季节性分层相关的非冰川碎屑纹泥。冬季泥质层中粘土矿物和泥晶碳酸盐矿物的混合沉积呼应于总体气候干旱背景。纹泥的发育与大幅度湖侵的同步性反映了区域构造运动对湖相纹泥形成的宏观控制;纹泥的物质组成、厚度等差异则指示了细微的环境变化。     

Experimental study on phosphorus release from sediments of shallow lake in wave flume

Influence of wave on sediment resuspension and nutrients release from sediments, collected from Lake Taihu and Lake Chaohu, was studied in flume experiments. Under strong-wave conditions, concentrations of suspended solids (SS), total phosphorus (TP) and dissolved total phosphorus (DTP) in overlying water were increased significantly following the sediments re-suspension. During the experiments on sediments of Lake Taihu and Lake Chaohu, TP concentrations increased 6 times and 3 times, and DTP concentration increased 100% and 70% more than it in presuspension, respectively. Concentration of soluble reactive phosphorus (SRP) of experiment on sediment of Lake Taihu increased 25%. During the massive sediment suspension, the dissolved phosphorus in pore water and much of the phosphorus adsorbed by the sediment particles were released into overlying water. The phenomena in this wave flume experiment are quite similar to the situation observed in situ of Lake Taihu. The critical wave stresses of sediment re-suspension are nearly equal. The change of concentrations of SS, TP, and SRP was the same as that in situ situation. This study showed that concentrations of TP and SRP in lake water could be increased significantly by wave disturbance. Phosphorus release was significantly enhanced by wave disturbance at the beginning of massive sediment re-suspension, but decreased later.