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1.
以内蒙古锡林郭勒盟苏尼特右旗的察干淖尔盐湖为研究对象,利用OSL(Optically Stimulated Luminescence)测年技术和DEM(Digital Elevation Model)数字高程模型,重建湖面波动历史,探讨湖泊形成与环境变化过程.通过对察干淖尔盐湖周边大量的野外考察,发现湖泊周围存在海拔高程为1020、978和973 m的三级古湖岸阶地,其OSL测年结果分别为29.2±1.3、18.4±0.8及8.2 8.0 ka.通过湖岸阶地高程恢复的上述3个时期的古湖面积分别为3600、500和400 km~2.与现今的干旱盐湖景观迥然不同. 相似文献
2.
对柴达木盆地察尔汗盐湖区外围沙下盐湖的卤水及沉积进行了综合研究。沙下盐湖卤水化学组成与地表径流和开放性盐湖卤水之间存在明显的差异性,具有高Na++Cl-、低Mg2++Ca2++SO42-、贫K++CO32-+HCO3-等特征。沙下盐湖析盐层位含有新生矿物并夹带碎屑矿物,其盐类矿物组合为:石盐+羟氯镁铝石+光卤石。25℃等温蒸发相图表明,其卤水演化方向往光卤石析出区迁移,在穿越上覆盖层通道中卤水发生的物理化学反应与独特的沉积特征,可以作为继续寻找沙下盐湖的指导。 相似文献
3.
为揭示太湖流域降雨和湖水酸根阴离子长期变化特征及环境意义，通过历史数据收集和采样分析，对太湖流域降雨和湖水中的SO42-、NO3-变化特征和来源进行了研究.结果表明：自1990s以来太湖流域降雨中SO42-呈显著下降趋势，年平均下降率为0.28 mg/（L·a）；NO3-浓度却呈显著上升趋势，年平均增长率为0.05 mg/（L·a），降雨中氮污染呈现加重的趋势.与之相反，湖水中SO42-呈显著上升趋势，年平均增长率为1.24 mg/（L·a）；NO3-浓度却呈显著下降趋势，年平均下降率为0.02 mg/（L·a）.30年以来，太湖水体SO42-/NO3-比值不断升高，远高于降水SO42-/NO3-比值.研究认为：流域SO2排放引起的酸沉降是湖水SO42-浓度增长的最重要原因，但氮氧化物排放并未引起湖水NO3-浓度升高，说明太湖流域对大气沉降的氮氧化物有滞留作用，而太湖水体是流域大气沉降硫酸盐的重要汇.综合治理太湖流域酸性物质排放对防止太湖水体酸化和治理富营养化都具有重要意义. 相似文献
4.
新疆艾比湖干涸湖底不同景观单元蒸发盐分布与变化特征 总被引：2，自引：0，他引：2
盐尘暴是由干旱、半干旱区尾闾湖干涸湖底及其附近盐质荒漠风蚀所导致的一种灾害性极强的天气现象.盐尘主要来自风蚀过程中干涸湖底盐分的释放.由于干涸湖底不同的植被覆盖状况,导致风蚀过程中盐分损失不同.为了解风蚀过程中不同景观单元下盐分分布与变化特征,选择艾比湖干涸湖底自然状态下典型的6种景观单元(胡杨林带(Landscape 1,简写为L1)、乔本结合带(L2)、草本结合带(L3)、芦苇荒漠带(L4)、梭梭荒漠带(L5)、无植被覆盖(L6)),于2011年6月初和10月初2次采集沉积物样品,运用方差分析方法,研究各个景观单元下盐分的分布与季节变化特征.结果表明:1)2次采样不同景观单元0~30 cm和30~60 cm处阳离子Na+、K+、Mg2+含量均存在显著差异,其中Na+含量存在极显著差异且含量最高,而不同景观单元0~30 cm和30~60 cm处阴离子Cl-、SO42-含量均存在显著差异,CO32-、HCO3-含量甚微;2)干涸湖底沉积物的主要盐分类型是NaCl,其次是CaSO4,其它盐分含量较小,且不同景观单元相同深度沉积物盐分含量存在显著差异.无论是盐分离子组成还是含量,L5均最高,其次是L6,而L2均最低.随着深度的增加,不同景观单元沉积物中的盐分含量均呈现降低的趋势.随着时间变化,景观单元L2、L3、L4、L5、L6盐分含量有不同程度的增加,而L1盐分含量减少;3)在小尺度范围内,局地气候条件相对均一,地下水矿化度、地下水埋深及沉积物性质差别不大,不同景观类型是影响盐分表聚的主要因素. 相似文献
5.
ABSTRACT Hydrogeochemical data of groundwater samples from 35 boreholes drilled in the Okposi-Uburu salt lake area are analysed. The data reveal that concentrations of dissolved geochemical constituents such as calcium (Ca2+), manganese (Mn2+), magnesium (Mg2+), chloride (C1?), and sulphate (SO2+ 4) ions show significant areal variations. Dissolved solids, chloride and manganese ions have concentrations up to and above the objectionable limits for drinking water in the salt lake area. Concentrations of dissolved solids in this zone are about 1200 mg 1?1. Concentrations of chloride and manganese ions are 350 mg 1?1 and 1.0 mg 1?1 respectively. These geochemical constituents and groundwater flow patterns show that transport of contaminants away from the source zone has been greatly influenced by advection, while in areas of high velocity dispersion is the controlling factor. Temperatures for the Okposi and Uburu salt springs are 34.4 and 37.5°C respectively. Bomb tritium indicated water of pre-1953 age. Deuterium and oxygen-18 showed high isotopic enrichment. The high concentrations of dissolved salts resulted from the combined effects of migration of dissolved salts through fractures at the lake floor and evaporation from the lake surface. These findings are related to the tectonic history of the Okposi-Uburu area. 相似文献
6.
Late Cretaceous paleoenvironment and lake level fluctuation in the Songliao Basin,northeastern China
Study of Late Cretaceous lacustrine sedimentary strata in the eastern Songliao Basin, China revealed that the paleoclimate was relatively arid and hot during sedimentation of the upper Santonian of the Yaojia Formation, but became relatively humid and warm during deposition of the lower Campanian Nenjiang Formation. The upper Yaojia Formation was deposited in a freshwater lake environment, while the lower Nenjiang Formation was deposited in a slightly brackish to brackish environment. The average total organic carbon content in the upper Yaojia Formation is 0.15%, while the hydrogen index is 36 mgHC/gTOC, implying poor source rock for oil generation and the organic matter comprised of a mixture of woody and herbaceous organic matter. In contrast, the hydrogen index of oil shale and black shale of the lower Nenjiang Formation is 619 mgHC/gTOC, and total organic carbon content on average is 3.37%, indicating a mixed algae and herbaceous source of kerogen and an increase in aquatic bioproductivity. The black shale and oil shale have low Pristane/Phytane and C29 5α,14α,17α(H) ? stigmastane 20R/(20R + 20S) ratios, with maximum concentration of n‐alkanes at n‐C23, implying an anoxic depositional environment with algae, bacteria and higher plants providing most of the organic matter. Relatively abundant gammacerane and a higher Sr/Ba ratio in the oil shales suggest the presence of brackish water and development of salinity stratification in the lake. During sedimentation of the upper Yaojia through the lower Nenjiang Formations, the level of Songliao lake increased and a deep‐lake environment was formed with bottom waters being oxygen depleted. Concomitantly, as the lake deepened bottom conditions were changing from oxic to anoxic, and the input of organic matter changed from predominantly higher plants to a mixture of bacteria, algae and higher plants providing favorable conditions for oil source rock accumulation. 相似文献
7.
伴随结冰过程的盐分排出是驱动冰封浅湖营养盐动态变化的关键过程,影响湖泊水质、环境与生态演变.为探究湖冰冻融过程如何改变寒区浅湖营养盐条件,采用自制定向冻结装置开展了无机氮磷营养盐溶液(NH3-N、NO-2-N、NO-3-N、PO3-4-P)的室内冻结试验,结合现场采样分析评估了冻结排出效应对典型浅湖氮磷营养盐的影响.结果表明:营养盐浓度、盐度(以NaCl表征)是影响冻结排出效率的关键因素;随营养盐浓度的升高,冰内营养盐浓度升高,但冻结分离系数减小;若盐度升高,冰内营养盐浓度和分离系数均增大,主要与未冻卤水泡的形成有关;3种形态的无机氮、磷酸根的分离系数均存在明显差异.将试验结果应用于内蒙古乌梁素海结冰期氮磷营养分析,计算表明湖冰冻结排盐过程不仅造成湖水各类营养盐浓度升高,同时改变无机氮素构成、氮磷比等营养结构状态;特别是若湖泊盐度发生变化,氮磷营养盐的冻结排出效率及其差异性均会显著改变,增加冰封期湖泊营养条件的时空变异性.本文结果可广泛应用于定量评价冰层冻融过程对冬季湖泊营养条件的影响,有助于理解冰封期浮游植物群落演变的内在驱动力. 相似文献
8.
淮北临涣矿采煤沉陷区不同水体水化学特征及其影响因素 总被引：3，自引：0，他引：3
为研究淮北临涣矿采煤沉陷区不同水体的补给水源及溶质来源,在现场调查的基础上,系统采集丰水期、平水期、枯水期沉陷区积水、地表河水和浅层地下水样进行测试分析,采用Piper三线图、Gibbs图和因子分析方法,对不同水体水化学特征及其影响因素进行讨论.结果表明:地表水水体总溶解性固体(TDS)质量浓度表现为枯水期丰水期平水期,浅层地下水表现为枯水期平水期丰水期,地表水TDS质量浓度明显高于浅层地下水.地表水中主要阴阳离子为Na~+、Cl~-和SO_4~(2-),水化学类型主要为SO_4~(2-)-Cl~--Na~+型;浅层地下水离子以HCO_3~-、Ca~(2+)和Mg~(2+)为主,表现为HCO_3~--Ca~(2+)-Mg~(2+)型.结合Gibbs图和因子分析可知,地表水受蒸发作用、地表径流以及采煤活动等因素影响,浅层地下水在一定程度上体现出大气降水和地表水补给的特点,受岩石风化作用影响较为明显. 相似文献
9.
Three types of brines with a characteristic composition have been distinguished in the Mezen Syneclise: with increased Na+, with relatively decreased Ca2+, and with relatively increased Ca2+. Rock salt dissolution has been shown to be substantial in the first-type brine formation. It has been noted that these brines are very dynamic and extremely young. The second-type brines have been shown to be of sedimentation origin and have a stagnant regime at relatively low temperatures; gypsum dissolution and metamorphization under stagnant conditions at increased temperatures have been shown to be substantial at the first and the following stages of formation of the third-type brines. 相似文献
10.
为了研究太湖底栖动物优势种类——霍甫水丝蚓(Limnodrilus hoffmeisteri)对于湖泊富营养化的影响,以温度和密度为模拟控制条件,对太湖霍甫水丝蚓进行营养盐释放的室内控制实验,研究温度和密度的变化对霍甫水丝蚓NH_4~+-N和PO_4~(3-)-P释放率的影响,根据霍甫水丝蚓铵态氮(NH_4~+-N)和磷酸盐(PO_4~(3-)-P)释放率与温度的关系方程,结合太湖霍甫水丝蚓2007-2010年的生物量估算其对太湖水体氮磷的潜在贡献.结果表明,随温度升高太湖霍甫水丝蚓NH_4~+-N和PO_4~(3-)-P的释放率均呈现逐渐升高的趋势,而密度变化对霍甫水丝蚓NH_4~+-N和PO_4~(3-)-P释放率的影响均不显著,太湖霍甫水丝蚓NH_4~+-N和PO_4~(3-)-P年平均释放量分别为1925.5和210.0 t,分别可达到全太湖沉积物-水界面NH_4~+-N和PO_4~(3-)-P的年净通量的19.3%和23.3%,表明霍甫水丝蚓的营养盐释放对于湖泊生物地化循环和湖泊富营养化具有显著的影响. 相似文献
11.
巴丹吉林沙漠湖泊水化学空间分布特征 总被引：7，自引：2，他引：5
通过对巴丹吉林沙漠腹地拐子湖-地质公园一线51个湖泊水,8个泉水,12个井水及1个雨水水样的水化学成分分析,初步探讨了沙漠湖泊水化学分布特征及其影响因素.结果表明由东南边缘至腹地湖泊总体上依次呈硫酸盐型-碳酸盐型-氯化物型分布.东南边缘以Na+、Cl-、SO24-为主的湖泊因矿化度分异,形成Ca2+、Mg2+含量不同的三种亚型,其中高矿化度的Na-Cl-(SO4)型湖泊在腹地湖泊群中也有出现,表现出地理上的不连续分布;边缘若干湖泊受局部地理环境的影响水离子多含Na+、Cl-、CO32-+HCO3-.综合分析表明湖泊水化学型的空间分异与区域气候差异和气候变化有关,湖水直接或间接地接受当地降水补给,但不排除外源地下水补给对其有一定贡献.通过对比不同时段部分沙漠湖泊水化学特征发现近十年以来腹地湖泊补给源或受气候干暖化影响使其水化学特性较边缘湖泊的变化大. 相似文献
12.
On the pumice flow deposits of the Asama volcano, Japan, many salts such as halite (NaCl), gypsum (CaSO4·2H2O), hexahydrite (MgSO4·6H2O) and mirabilite (Na2SO4·10H2O) crystallize at the base of south-facing valley cliffs. The zone of salt efflorescence and of resulting polygonal rind correspond to the zones of notch formation and high water content. The main conditions for salt crystallization and polygonal rind formation are: (1) the existence of groundwater containing a high concentration of Cl?, SO, Ca2+, Mg2+, and Na+; (2) a valley cliff material with a high capillary action and small tensile strength; and (3) low humidity and a high ground-surface temperature derived from the direct incidence of sunshine. Given the right conditions, salt weathering can occur not only in the arid regions but also in humid, temperate inland regions. 相似文献
13.
河西走廊花海古湖泊全新世白云石的发现及其环境意义 总被引：4，自引：3，他引：1
通过对河西走廊花海古湖泊沉积物的X衍射分析发现,全新世期间有明显的白云石沉积.岩性、沉积过程、石膏以及Fe3+含量的变化表明,花海湖全新世白云石沉积环境以还原环境为主,即还原环境利于白云石的形成,为白云石的成因研究提供了新的证据.白云石作为碳酸盐矿物,可以反映湖水盐度,但并非直接指示了湖水的咸化.随着湖水盐度的进一步增加,在硫酸盐型湖泊中,白云石含量随盐度的增加而相应减少,表明利用白云石分析湖水盐度时需要结合其他矿物进行分析.结合石膏含量的变化,花海湖全新世时期白云石含量的变化可以揭示该区域湖水盐度的变化.在10.478.87 cal ka B.P.早全新世时期,湖水的盐度较高,气候由干向湿转变;8.87 cal ka B.P.时期,有大量石膏沉积,显示了湖水盐度的进一步升高,气候干旱;随后湖水相对淡化,气候湿润;5.50 cal ka B.P.至今,沉积出现间断,气候逐渐干旱. 相似文献
14.
Modern digital conductivity meters are readily portable, robust, cheap, and give precisely reproducible values of specific electrical conductivity (SpC, in µS cm?1). Here we investigate the accuracy of their estimates of the amounts of gypsum dissolved in waters collected in gypsum karst terrains, expressed as total hardness (TH) in mg L?1 of CaSO4·2H2O (GYP). Total dissolved solid concentrations (TDS) are also considered. Curves obtained with the program PHREEQC, for the dissolution of pure gypsum in water at 25 C, are compared with 574 comprehensive water chemical analyses selected from gypsum karst studies in Europe and the Americas. Principal common and foreign ions encountered are the BNC group (bicarbonates, nitrates, chlorides). It is found that GYP = 1·12·SpC + 62 where BNC < 33% (Cl? < 5%), with one standard error <5% for waters with SpC > 2400 µS cm?1; GYP = 0·74·SpC + 777 where BNC < 33% (5% ≤ Cl? < 15%), with one standard error <10% for waters with SpC > 3100 µS cm?1; GYP = 0·97·SpC ? 209 where BNC < 33% and Cl? ≥ 15%, with one standard error <10% for samples with SpC > 4300 µS cm?1. There are similar results for the more complex waters found in gypsum karsts where much carbonate rock or salt is also present, to the limit of BNC < 50% for what may reasonably be defined as ‘gypsum waters’. Values of R2 for linear correlations of different subsets of the water samples range from 0·69 to 0·96, the majority being >0·8. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
15.
Jonathan B. Laronne 《地球表面变化过程与地形》1981,6(6):541-552
Inquiry into the dissolution kinetics of naturally occurring geologic materials, rather than individual mineral species, has been relatively neglected. This is especially true of surface processes, the realm of surface water hydrology and geomorphology. This paper focuses attention at a laboratory study of the rate of such complex reactions. Functions defining the dissolution rates of saline (0.1–20 per cent salt content) Mancos Shale-associated alluvium in distilled water follow varying patterns. Dissolution is characterized by an initial (<5 min) high rate constant, by a following phase (20 min-57 h) where rates are reduced drastically, and by a final period of encroachment to equilibrium. Initial dissolution rates increase with increase in salt content and sediment: water ratio. The time necessary to approach equilibrium is, however, found to be directly proportional to the sediment; water ratio. The concentration of Na+, Mg2+, Ca2+, SC2?4 and HCO?3, and the relative abundance of Ca2+ and HCO?3 increase continuously with contact time, indicating that the hydrated sodium and magnesium sulphate minerals provide most of the initial solutes, though not necessarily most of the total solute bulk. The results obtained in this study indicate that the high initial dissolution rate of soluble minerals from alluvium, and particularly from shales in contact with aqueous solutions, is too short-lived to account for most of the solutes occurring in heavily sediment-laden surface flow. Excluding input from slower, usually supersaturated subsurface flow, dissolution from sediment in transport should be a major source of solutes in originally undersaturated and kinetically unequilibrated surface water in semiarid and arid regions. 相似文献
16.
ZhiYong Han XuSheng Li Yong Wang XianYan Wang ShuangWen Yi HuaYu Lu 《中国科学:地球科学(英文版)》2016,59(7):1378-1389
There has been a significant debate about the nature and causes of the Pleistocene evolution of the Nihewan Basin, North China. We studied the eastern Nihewan Basin sedimentary facies at two main sites, Hutouliang and Donggou. A combination of field observations and measurements of sediment grain-size distribution was used to reconstruct the sequence of sedimentary environments since the middle Pleistocene, and optically-stimulated luminescence measurements were used to date the sediments. Our results indicate that a shallow lake occupied the basin center along the Sanggan River, probably lasting until ~440 kyr ago before disappearing completely ~340 kyr ago. It was succeeded by a phase of fluvial-dominated sediment accumulation which ended ~30 kyr ago. We suggest that the formation of the gorge resulted from the relative uplift of the Niuxin Mountain along the Liulengshan fault ~140 kyr ago. However, since ~30 kyr ago the fault may have become inactive and the river downcutting near Shixia was no longer offset by the relative uplift, which caused a shift from deposition to denudation in the Nihewan Basin from then on. The disappearance of the paleolake ~340 kyr ago may have been the culmination of the ongoing process of basin infilling. 相似文献
17.
通过模拟沙湖沉积物-水系统,以沙湖原水氟离子（F-）浓度为1倍浓度（0.69 mg/L）,设置0.5倍浓度、1倍浓度、1倍浓度灭菌、2倍浓度和4倍浓度共5个实验组,探究不同上覆水F-浓度背景下沙湖沉积物中F-的迁移.结果表明,沉积物F-的释放量随上覆水F-浓度的增加而呈下降的趋势,其中2倍和4倍浓度组的沉积物由释放F-转变为吸附F-.碱性水体有利于沉积物F-的释放,即随着pH增大,F-释放量也会增加.微生物的Beta多样性层次聚类分析表明,F-会抑制Paenisporosarcina与Thiobacillus的相对丰度,但对Fusibacter的生命活动具有促进作用.根据各浓度组间优势菌属相对丰度与环境因子的冗余分析可得,Acinetobacter、Thiobacillus相对丰度与pH呈负相关;Fusibacter相对丰度与F-浓度呈显著正相关,而Thiobacillus的相对丰度则与F-表现出弱负相关.通过对各浓度组中重要离子的分析发现,0.5倍组和4倍组中F-的迁移受Ca2+、HCO3-和SO42-浓度影响较大;相关性分析表明0.5倍浓度组的Ca2+、HCO3-浓度与F-浓度呈极显著正相关,而4倍组中F-浓度和Ca2+、HCO3-浓度呈负相关,SO42-浓度和F-浓度的相关性则是0.5倍组呈负相关,4倍组呈极显著正相关.本文在不同上覆水F-浓度背景下全面探究了沙湖沉积物中F-释放和迁移机理,为沙湖及其他含氟地表水的氟污染防治提供理论支持. 相似文献
18.
This study uses stable isotopes and major ions to examine the seasonal evolution of penitentes on the surface of Tapado Glacier, in the Norte Chico region of the Chilean Andes. A snow pit was sampled in November 2011, and penitentes were sampled during the summer (December 2011 and January 2012). The major ion load of the winter snowpack is dominated by Ca2+ (60%), SO42? (16%) and NO3? (13%), and there is little influence from marine air masses at the site, with most SO42?, Mg2+, Ca2+ and Na+, derived from non‐sea salt sources. During the early ablation season we observe increases in stable isotope ratios and major ion concentrations (particularly lithic ions Na+, Mg2+ and Ca2+) in the upper reaches of penitentes, which is attributed to sublimation and the aeolian deposition of dust particles. In the late‐summer, melt replaces sublimation as the dominant ablation process and results in smoothing of the stable isotope profile and the elution of major ions within the penitente snow and ice matrix. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
19.
Groundwater salinization has become a crucial environmental problem worldwide and is considered the most widespread form of groundwater contamination in the coastal zone. In this study, a hydrochemical investigation was conducted in the eastern coastal shallow aquifer of Laizhou Bay to identify the hydrochemical characteristics and the salinity of groundwater using ionic ratios, deficit or excess of each ions, saturation indices and factor analysis. The results indicate that groundwater in the study area showed wide ranges and high standard deviations for most of hydrochemical parameters and can be classified into two hydrochemical facies, Ca2+‐Mg2+‐Cl‐ facies and Na+‐Cl‐ facies. The ionic ratio, deficit or excess of each ions and SI were applied to evaluate hydrochemical processes. The results obtained indicate that the salinization processes in the coastal zones were inverse cation exchange, dissolution of calcite and dolomite, and intensive agricultural practices. Factor analysis shows that three factors were determined (Factor 1: TDS, EC, Cl‐, Mg2+, Na+, K+, Ca2+ and SO42‐; Factor 2: HCO3‐ and pH; Factor 3: NO3‐ and pH), representing the signature of seawater intrusion in the coastal zone, weathering of water–soil/rock interaction, and nitrate contamination, respectively. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
20.
Lake Gucheng is located in the southeast of Nanjing, with an area of 24.3 km2, an average depth of 2 meters. The macrophytes of the lake were used to be abundant and their biomass was about 4.96 mg·m-2. The annual average contents of total phosphorus (TP), total nitrogen (TN), PO3- -P, CODMn and BOD5 0.03, 1.31, 0.005, 3.61 and 1.46 mg·L-1, respectively. Thus, the water quality of this lake is quite well. Recently, the water quality in pari of the lake became worse because of some unreasonable exploitation and utilization of bioresources. The interactions between phytoplankton (N1), macrophyte (N2), fish (N3), crab (N4) were studied here. The macrophyte has great influences on both phytoplanktons, fish and crab, controlling the water quality and maintaining the fishery productivity. On the other hand, the phytoplankton, fish and crab also influence the macrophyte. It is key method of ecological management to maintain the macrophyte by fishery culture. Therefore, a modified Lotka-Volterra model has been established to estimate the interaction between N1, N2, N3, N4 and the influences of some water environmental parameters on these aquatic organism, environmental and economic effect. The main model consists four compart-mental models and four submodels, involved 12 external variables, 8 state variables, 19 universal constants and 11 parameters. The values of most parameters were found from our experiments and calibrated by the model and actually measured data. The model has been validated by comparison the computed and experimental data of phytoplankton and macrophyte. The theoretical outputs showed a good agreement with the measured data. This model predicated that if the standing crop offish and crab was higher than 2.65 ·m-2 during springtime in this lake, macrophytes would not grow, chlorophyll a content would arrive 34.8 mg·m-3 and the water quality would decrease. If the macrophyte grow well, the maximum fishery productivity would be about 1 600 t. In this case, the annually averaged phytoplankton chlorophyll a content should be 3.69 mg·m-3, which is lower than the criterion (10 mg·m-3) for eutrophic state. From 1991 to 1996, Lake Gucheng was managed with this model, its water quality maintain quite well, chlorophyll a content decreased from 3.51 (1991) to 1.89 mg·m-3 (1994). Meanwhile, the fishery productivity increased and the economic effect heightened year by year. 相似文献