Abstract:Cyanotoxins produced by cyanobacteria have caused pollutions in land surface water around the world.The most common toxin is microcystin,a cancer inducing hepatoxin.Microcystin is chemically stable in water and can't be effectively removed by conventional water treatment processes. Microbiological removing,especially bacterial degrading was an effective way to eliminate microcystins from water. In this research,Cyanotoxin degrading bacterium strain S3 and Chlorella elldpsodea LI were co-immobilized by sodium alginate to degrade microcystin-LR (MC-LR).Results showed that the alga could increase the growth of strain S3 in the gel beads. The coimmobilined bacteria had a higher degrading efficiency of MC-LR than independent immobilized cell. The degrading efficiency ofimmobilized cells was influenced less than the free cells when temperature and pH changed.When the immobilized cells were reused, they could maintain high degrading efficiency.

Abstract:Because a lot of nitrogen and phosphorus flow into lakes and rivers, water bloom frequently occurs inworld scope. Recently a sori of Peridiniopsis sp. bloom was appeared in Lake Donghu, Wuhan. The Peridirtiopsisap. can adapt well to a large,,of temperature. The algal bloom lasted a long time and the maximum density ofPeridiniopsis ap.reached as high as 2. 54 x 10⁷ cells/L. In the paper, population dynamics of Peridiniopsis ap.andits relationship with environmental factors in Lake Donghu were studied. The correlation analysis indicated Peridini-opsis sp.be remarkable positive wrrelation with the concentrations of TP _surface,TN_1.2metermand N0₃-N _surface. However, the concentrations of TP, TOP, TN, TON, PO₄-P and NH₄-N were raised just a day before blooming and feVto lowest after blooming. Suitable strength of illumination may be a triggering factor for blooming. In addition, itcan be found from the composition and distribution of phytoplarJcton in some sampling stations that in certain degreewind can make Peridiniopsis ap. gather and cause bloom. The development, occurring and dying out of algal bloomwas observed. When the alga bloom died out, a lot of Peridiniopsis ap. sunk down toward lower layer. By analy-zing, authors consider many environmental factors lead to water bloom together.

Abstract:The aim of this paper is to study the polysaccharide of the native water-bloom cyanobacterium Microcystisspp. and its effect on chemical and ecological properties of aquatic environments.Polysaccharides from the water-bloom cyanobacterium Microcystis spp. of Lake Dianchi were extracted with deionized water, pH5 and pH9.2 bufferat 4*C and 80*C.Partial chemical charactristics of extracted polysaccharides was investigated. The results showedthat pH 9.2 buffer got the highest yield that was 2.25%.The lowest yield was 0. 383% with pH5 buffer. The solubility test indicated that polysaccharides extracted by various methods were insoluble, partly solubilized or dispersedin the examined solvents.The monosaccharide composition analysis with GC and GC-MS indicated the extracted polysaccharides contained rhamnose, arabinose, mannose, galactose, glucose and one unknown sugar. The sulfuricacid carbazole method showed the presentation of uronic acid in the extracted polysaccharides.The metal contentwas determined with inductively coupled plasma quantometer. The polysaccharide extracted with deionized water at4*C was found to contain high concentration of Ca and Mg, which was 2.15% and 0.4%,respectively. Preliminary study indicated that the polysaccharide from Microcystis spp.was acidic heterogeneous polysaccharides. The lowsolubility of the polysaccharide showed it may form transparent exopolymer panicles easily in natural water. Thehigh metal-binding capability of the polysaccharide showed it may influence the solubilization,precipitation, bioavailability, and cycling of metals in aquatic environments, especially Ca and Mg.

Abstract:Eutrophication and wave action caused by wind,two important factors determining the phytoplanktonstructures in large shallow lakes. Based on the investigations from October 2003 to September 2004 in Meiliang Bayand Lake Wuli,situated in the northwest of Lake Taihu, the third large shallow lake in China, the spatial distribulion and seasonal variation of environmental variables and phytoplankton community were analyzed to test if trophiclevel and wave action caused by wind were important for phytoplankton community. The results showed that:(1)Meiliang Bay and Lake Wuli were different in trophic states and wave action caused by wind, the former was moreseverely affected by wind and the latter was more eutrophic.(2) The annual mean of the total phytoplankton bio-mass in Lake Wuli (6.85 mgL) was much higher than that in Meiliang Bay (4.99 mgL).The monthly meanreached the maximum in summer and autumn while the minimum in winter in both bays. Seasonal variation of domi-nant phytoplankton assemblages and species in Meiliang Bay was as follows; Bacillariophyta(Cyclotella spp.)andCryptophyta(Cryptomonas app.)in winter, Chlorophyta(Planctonema sp.)in spring, Chlorophyta(genera of Chlorococcales order such as Scenedesmus spp. and Pediastrum spp. et al.),Cyanobacterias (Microcystis spp. andPlanlaothrix app. lt7xillatoria app.),Bacillariophyta (Aulacoxira spp. /Melosira spp.)in summer, Cryptophyta(Cryptomonas spp) in autumn, while the seasonal succession in Iske Wuli was somehow vague. Cryptophyta(Cryptomonas spp.)dominated throughout the year. Sub-dominant or co-dominant species are Bacillariophyta(Aul-acoseira graruilate and Cyclotella spp.)in winter, (:hlorophyta(genera of Chlorococcales order and Cltlamydomonasapp.)in spring, Cyanobacterias (Planktothrex app. and Microcystis app.)and Euglenophyta(Euglena app.)insummer, Baciflariophyta (Aulacoxua app.)in autiunn. 'f1}e difference of phytoplankton community between twobays was resulted mainly from their eutrophic station and wave action caused by wind. (3)Compared with classicalPEG(Plankton Ecology Group) model,the seasonal succession of phytoplankton community in Meiliang Bay andIake Wuli showed some similar pules and they were mainly affected by water temperature, light, nutrient(nitrogenand phosphorus) and the grazing of zooplankton. However, the succession may fluctuate due to the effect of eutrophication and wave action caused by wind. More studies are needed to understand seasonal succession of phytoplankton community in large eutrophic shallow lakes.

Abstract:Seasonal variations in rotifers of the waters with diR'erent eutrophication states(the open water area,Meiliang Bay, Iske Wulihu) in Iake Taihu were studied during Oct. 2003-Sep. 2004. The concentration of nutrients was the highest in lake Wulihu and lowest in the open water area. The species number and biomass of rotiferswere the highest in lake Wulihu and lowest in the open water area. Regression analysis suggested that there was asignificant positive correlation between the number of rotifers and the concentration of TN and Chl. a; and the biomass of rotifers was also significantly correlated to the concentration of Chl. a. The study indicated that the structureof rotifer was significantly different among the three areas in lake Taihu. It also suggested that eutrophication hadsignificant effect on the structure of rotifer community in lake Taihu.

Abstract:The Lake Nanhu (30°29'N,114°21'E) situated in Wuhan City, Hubei Province of China, is an eutrophic shallow lake along the middle reaches of the Yangtze River, with a main surface of 550 hmZ of aquaculture.Macrozoobenthos were collected at 5 sampling sites both seasonally and randomly in the Lake Nanhu during the period of investigation from August 2005 to May 2006. With the input of massive nutritional salts and the deteriorationof the water quality, the community structure and biodiversity of macrozoobenthos had changed in the Lake Nanhu.Few species like mollusk had already been seen in the lake. Predominant species were limnodrilus hoffmeisteri,Tubifex,tubifex, Branchiwa souxrbyi, Tanypus pua.}t如nnis and Propsilocerus akamus at present. Level distributionsdensity of L.hoffmeisteri were V>Ⅲ>I<>I>N and T. punctipennis were II>I>>Q>N>V .The largestdensity of L ho ffmeisteri in May was 3802 ind. /m²,so was the least in August The largest density of T. pu>2. The largest distributions depth was 25 cm, while 99% of Oligochaeta and Chironomid larvae lived in depth of 0-20 cm in the sediment. Wet weight biomess of Oligochaeta's was 176759. 35kg, Chironomid larvae was 46810. 30 kg, and freshwater snails was 899. 34 kg in Lake Nanhu. Macrozoobenthos canclear away 3463.61 kg TN and 350. 92 kg TP from the lake, but their efficiency is limited, compared with huge nutrition salt source of the lake.

Abstract:Before 1980s, there were over 107 species belong to 25 families of fish in hke Taihu, which can be divided into 4 ecological group, i. e.,migratory, river-lake migratory, potamophilus and limnocolous. A total of 60species of fish belong to 18 families were collected in the lake from Sep. 2002 to Jan. 2006. Among them, 4 species(Megalobrama amblycephala, Cirrhinus molitorelGa, Carassius auratus gibelio and Oreochromis niloticus)weretransplanted into the lake. From 1960s to now, grass carp, black carp, silver carp, bighead carp and blunt snoutbream were stocked mainly with the artificial cultural fingerling. From 1978 to now, the stocking object of eel(Anguilla japonica) were natural fry collected from the Yangtze River. During the end of 1950s to 1985,duo to"river-lake blocking0 caused by artificial interruptions between the Yangtze River and Lake Taihu, the recmitmentof those fish species that can not spawn in standinE; water were disappeared and natural fish resources of the lakehad steadily declined. Moreover, reckless ove}shing and inadequate protection of the spawners caused the diminulion both in the size of fish species and of individual fishes, resulting the lake being dominated by species of smallsize as well as by populations of stunted growth. The optimization of fishery strategy for the lake has been put forward in view of the above results and environmental effect.

Abstract:Based on hydrological risk, the risk measurement indicators for various flood avoiding agriculturalterns are introduced in wetland restoration area in Lake Poyang. According to the values of these indicators,the benefit and risk of various flood avoiding agricultun patterns are analyzed.And then using benefit maximization and risk minimization as objective functions, a multiobjective planning model of integrated flood avoiding economic patterns is constructed.Several typical noninferior solutions to the model are generated by applying weighting method.The tradeoff' analysis of benefit and risk for different noninferior solutions, which indicates that planting vegetajectivehigh benef t and low risk pattern but surface aquaculture is a high benefit and risk pattern, may provide obfoundation for risk decision making of flood avoiding agriculture in the wetland restoration area.

Abstract:According to Basic Analytical Methods of Environmental Quality Standards for surface water, GB3838-2002,we used the 1983-2004 monitoring data to evaluate and characterize water quality condition and to analyzewater quality temporal-spatial evolution trend of Lake Dongting, based on the application of comprehensive indexmethods such as Nemerow Index. The results showed that Water quality changed in Lake Dongting which fluctuatedbetween up and down temporally. In 1983-1985,water quality was clean in Lake Dongting. From then on, waterquality had been polluted seriously in 1988 and graduated in light pollution after 199 f,and then ran down in 1999and dropped to light pollution in 2001 again, as well as had begun to aggravate in 2004. The main pollutant was to-tal phosphorus (TP) in Lake Dongting. Water quality was worse in the flood water season than in the other waterseasons, but after 2002,water quality was worse in the flood water season had been better than in the normal water season.The water pollution could be more~in the entering riverways than in the lake bodies of Lake Dongting spatially. Water quality in Lake Weat Dongting was worst, in lake South Dongting was worse, and in Lake East Dongtingwas not polluted badly.

Abstract:Dredging and aquatic macrophytea reestablishment were carried out in the West Lake Wuli of LakeTaihu. Total phosphorous and total nitrogen in the water, as well as different forms of phosphorus and nitrogen inthe sediment cores of different areas were investigated in different seasons to examine the effects of different restoralion measures. The results showed that, the distribution of nitrogen and phosphorus in the water and sediment underdiflferent ecological restoration were different. The content of nitrogen and phosphorus in the water in dredging onlyarea and control area was lower than other areas .Vertical distribution of different forms of phosphorus in the sediment of West Lake Wuli varied with different ecological restoration measures. Macrophytes reestablishment afterdredging affected Lab-P,AI-P}Fe-P observably, other than Ca-P and Org-P. In the former-fishery area, Ca-P andorg-P took up the largest proportion in the total phosphorus, followed by Fe-P. However, Fe-P and Ca-P took upthe largest proportion in the dredging only area.Compared with TP, the effects of ecological restoration measures onTN were not so obviously. In dredging only area,the contents of nitrogen and phosphorus in both the water andsediments were high, the long-term effects of dredging needed further study. In the area of dredging plus macro-phytes reestablishment, the content of TN and TP was the lowest, with plenty of aquatic macrophytes. It was sugested that the effective way of eutrophicated lake control may be actualizing through reestablishment of aquatic macrophytes in the dredging area by the precondition of reducing external source pollution.

Abstract:Based on the monitoring data obtained from Lake Dongting in November 2005,the concentrations of theheavy metals in water and organisms were analyzed, and the pollution assessment of heavy metals in organisms wasmade. The results showed that the concentrations of heavy metals in water were lower than Type I of the People' sRepublic of China, the concentrations of heavy metals in Penaeus~Boom were higher than in Bellamyaquadrates and in fish, and the concentrations of heavy metals in demersal fish were higher than that in pelagic fish,and the concentrations of heavy metals in predatory fish were higher than that in herbivorous fishes. In LakeDongting, the pollution indexes of Cd, Pb, As in Penaeua vannwnei were higher than that in Bellamya quadrates,and higher than that in fishes; the pollution indexes of Hg in fish were higher than that in Bellamya quadrates,andin Penaeus vannwnei.

Abstract:Three sites were selected for samples in Lake Taihu to observe temporal and spatial distribution of redoxpotential(Eh),pH, total nitrogen (TN),total phosphorus (TP) and organic matter(OM) in sediments. Belowthe surface of sediments Eh declined rapidly with the increase of sediment depth and it was under anaerobic condi-lion except the top layer of sediment. pH value changed silightly in the profile of sediments, which ranged from 6. 4to 7. 8. With a comparison between four seasons, p.H value was the lowest in winter. TN and TP concentrations insediments of Lake Taihu were higher, and the maximum concentrations reached 2. 68 mg/g and 0. 864 mg/g. respectively. Their vertical profiles showed that TN snd TP concentrations in surface sediments were much higherthan in deeper layers and decreased steeply with the increase of the depth on the top 15 cm of sediment layers. OMconcentrations declined rapidly al the top 15 cm of sediment layers, but there was little change in four seasons. Thesediment loads of TN and TP were much higher at Sl than that at other sites.

Abstract:Characteristics of hydrrology periods was analyzed according to the seasonal characteristics of precipitation,evaporation,dissolved snow and groundwater, and impacts of seasonal hydrological periods on soil organic matters were studied based on field investigation and laboratory analysis in the meadows of Napahai wetlands. The resulfa showed that water level fluctuated greatly in the meadows and soil organic matters were driven greatly by seasonal hydrology periods.巧namics of organic matters in 0-20cm layer appeared in an anomalous"W " shapewhile"N" shape in 20-40cm layer. The driving processes of soil organic matters in the meadows can be fitted inGauasian model.

Abstract:Nowadays, research on ran-point source pollution which comes from agricultural activities has become ahot-point and diffcult-point issue in the area of enriromnental problem. But currently few researches have been made onnon-point~pollution in trough scale. By using big soil trough and artificial rainfall equipmern to simulate nature precipitation and flow in uncovered sloping field, a physically-based model based.ANSWERS-2000 and,combined submodules of ANSWERS-2000 is developed to study transfer rule of dissolved nutrient(Nitrate-Nitrogen) in the soil trough during single precipitation. The model had been validated three times. Total runoff errors werebetween 4%-15% andCP_Awere between 0. 7-1 2. Accordingly, total Nitrate-Nitrogen errors~between 9%-17% and CP,,~between 0. 6-1. 1. Results showed that the simulation value of runo$ and Nitrate-Nitrogen-centration basically accords with the observed value. The modelbe used to calculate the transporting amount ofNitrate-Nitrogen in trough scale during single precipitation and had some reference values for future research.

Abstract:SCS model is adopted in this paper to simulate surface runoff' for Lake Fuxian catchment. The modelconsiders the spatial diversities of the Iand surface via dividing the catchment into a number of hydrological responseunits(HRU) based on diH'erent landuses and soil types. The surface runoff for each HRU is calculated and the totat surface runoff into the lake is modeled. CN values of the SCS model are calibrated场matching the modeled resulfa with the observed ones for the gauged river catchments of Liangwanghe and Dajiyugou. The model is then opplied to other ungauged areas of Lake Fuxian catchment after making slope corrections of the CN values. The modelindicates that the total surface runoff is 174 million ms for a one-year period of March 2005 to February 2006,withan average runoff cae}cient of 0. 395. The model is believed to be helpful in guiding further field observations. Themodeled results are also useful in constructing more detailed hydrological models as the next step, and in calculating mass of pollutants loaded to the lake.

Abstract:Through analyzing the data of K, Li and B in the mining area of Lake Xitaijinair, the study results revealed the dynamic changes of K, Li and B and their seasons during early mining(from 2003 to 2004).The resultsshow that the changes of contents of K, Li and B in lake brine mainly are controlled by the seasonal changes of surficial runoff. Three elements' contents in underground brine during recovering are higher than those during mining.But their contents in pore brine are higher than those in intercrystalline brine and three elements'spatial differentialion are obviously different. Studies on the phase diagram suggest that the brine during recovering has arrived thestep when the sylvite is precipitating. The brine in mining area is basically in stagnation and there was no signiGcant correlation between water levels and three elements'contents in underground brine. The changes of K, Li andB in underground brine probably are due to the physical and chemical changes of brine itself. And in short time,mining action and surficial runoff' can not evidently influence the elements'changes in hydrochemistry.

Abstract:Based on a one-dimensional eddy diffusion model, the model for studying the heat and mass exchange between the atmosphere and water body is developed, in which the phase change of water in winter and summer is included and the importance of the convective mixing process is emphasized. The model uses enthalpy instead of temperature as the forecast variable, which helps us to easily deal with phase change process. The model ie verified by observed data of lake ICinneret, which emphasizes adding convective mixing ptocesa is in accord with the practicalphysical mechanism of heat and mass exchange between the atmosphere and water body. The sensibility tests of wind velocity and surface friction velocity of lake verify their great influence on lake surface temperature and latent heat.

Abstract:Water surface spectra, which can work irradiance ratio just beneath water surface R(0^-)out, is obtained by ASD FieldSpec Hand-Held Spectro radiometer. When the in-situ data is collected, a certain special angle has been adopted. After analyzing the relationship between spectral characteristics of R (0^-)and chlorophyll-a concentration, the results showed that the strongest correlations appeared at 762 nm,727 nm and 496 nm, the values separately were 0. 85,0. 84 and-0. 80. The model analysis with single band and band ratio revealed that the quadratic models, of which independent variables were R(0^-)₇₆₂ .R (0^-)₇₆₂ R(0^-)₄₉₆,R(0^-)₇₂₇/R(0^-)₄₉₆.,were better than others. RZ separately reach 0. 923,0.919,0.916; std. error of the estimate S separately were 0. 012,0. 013,0. 013;F separately were 101. 241,96. 576,92.925. Make use of the 10 surplus samples to estimate three quadratic models and carry on the accuracy and error margin examinations. Then find that the quadratic model with the independent variable R(0^-)₇₆₂/R(0^-)₄₉₆was the best, and to a certain extent had some functions onchlorophyll-a concentration estimation in lake Taihu in summer. In addition, try to apply differential calculus to R(0^-)to estimate chlorophyll-a concentration, and can not acquire the better result.