Abstract:The ecoregionalization based on lacustrine nutrients is the basis of nutrient benchmark and trophication control criteria of lakes, and is also the scientific basis and magnitude pathway of compositive evaluation, prevention, control and management.In this paper, after analyzing the concepts on ecoregion, hydroecoregion, and discussion on the base of classification, the lacustrine response to nutrients in geographic sections, driving factors and models, we proposed a Chinese hydroecoregional frame based on regionalization, classification and phase.By analyzing the environmental factors that influencing trophic status, we determined the criterions for lake regionalization, including by climate zone, topography and water system;by topography, soil nutrients, land use, shape of lake basin(water depth, surface area, development of lake shore) and hydrologic characteristics(residence time, water level, degree of mineralization);by nutrient content(nitrogen, phosphorus et al), total primary productivity(biomass of phytoplankton, attached alga and aquatic macrophyte), and by dominant plant types(phytoplankton and macrophyte).We prima-rily constructed indices system of ecoregionalization for Chinese lakes and this work lays a basis of lake ecoregionalization based on nutrients in China.

Abstract:The policy'The development campaign of the western regions'has great significance for balancing the developing disparities between different regions and improving the economic strength of China.The fragile ecological environment of the western regions determines that ecological protection should be set as the basic point, and that economic development should be combined with sustainable development in those regions.This paper systematically formulates major problems and control measures of aquatic ecosystems in Inner Mongolia-Xinjiang Plateau, where is under the influence of climate change and human activities.We choose Lake Wuliangsuhai, Lake Hulun, Lake Bosten, Lake Chaiwopu and Lake Ebinur as typical examples and analyze the changes in water ecological status in the recent decades.It is confirmed that the degradation of water ecological environment occurs.This paper aims at understanding the current characteristics of lakes in Inner Mongolia-Xinjiang Plateau and providing theoretical support for reasonable development of lake resources and protection of water ecological environment.At present, lakes in Inner Mongolia-Xinjiang Plateau is arid and semi-arid and there exists many problems, such as lake size shrinking, salinization, sediment, deterioration of water quality and structural changes of aquatic ecosystem.Compared with lakes in east China, the research on the Inner Mongolia-Xinjiang Plateau in our country lacks of systematic knowledge and lagging relatively, although some basic research and information have been developed.In the future, the following fields will be focused on:(1) the evolution and trend of water environ-mental quality in the Inner Mongolia-Xinjiang Plateau under the influence of climate change;(2) the effect of water allocation on regional hydrodynamic conditions, pollutant transport process and the influence of water scheduling to important environmental factors;(3) selecting characteristic physical and chemical factors of water environmental in the Plateau, such as mineralization degree, to examine their influence on the aquatic biological communities;(4) exploring aquatic ecological restoration technology which is suitable for arid and semi-arid regions.

Abstract:To investigate the spatio-temporal heterogeneity of water quality in Lake Bosten, water qualities of six stations were mo-nitored from June 2010 to June 2011.The results showed that water qualities were distinctly different among stations, and monthly variations of water quality among stations were not uniform.In the open lake area of Lake Bosten:the water quality was the worst in northwest;whereas water quality in the river mouth of Kaidu River was the best, though changed greatly from month to month.In the less-open lake area of Lake Bosten:water quality was the best in Lake Lama(GradeⅠto Ⅲ);water quality in lake wetlands was the worst (Grade Ⅴ or even worse).The main pollutants in Lake Bosten were salinity, total nitrogen, sulfate and chloride.In general, the trophic level of Lake Bosten is mesotrophic, and sometimes it reaches light eutrophic.Agricultural non-point source pollutions, hydrology, lake currents and aquatic plants were the main factors attributed to the spatio-temporal heterogeneity of water quality in Lake Bosten.Analysis of the variation of water quality in the past 50 years shows that Lake Bosten has converted from the largest inland freshwater lake to a brackish lake since 1970s.The process of salinization could be divided three stages:rapid rise, slow decline and increase again.Accompanied with the lake salinization, concentrations of other pollutants increased rapidly as well.Overall, the variation of water quality in Lake Bosten is controlled by natural factors and human factors.In recent decades human activities have exacerbated the salinization and eutrophication of Lake Bosten.

Abstract:In order to study the spatio-temporal patterns of cyanobacteria blooms, it is important to detect and monitor them effec-tively by satellite observations.However, such detection and monitoring by low resolution data induces a scaling bias.Based on MODIS(250 m and 500 m) data at Oct.17, 2005 and Dec.3, 2010, the area of cyanobacteria bloom in Lake Taihu was derived by a approach named Floating Algae Index (FAI).The low resolution FAI was then achieved in two ways:FAI₅₀₀, was directly calcu-lated from MODIS(500 m);and the FAI_mean was the mean of FAI₂₅₀ which was directly calculated from MODIS(250 m).Results reveal a serious overestimation of FAI₅₀₀ and the area of cyanobacteria bloom due to the scale error all over Lake Taihu.The causes for scaling error are discussed and it is found that the spatial heterogeneous is the key factor which may lead to the error in the de-tection and monitoring on cyanobacteria bloom.

Abstract:By the synchronous environmental monitoring of 49 inflow and outflow rivers of Lake Taihu, this study analyzed the wa-ter quantity and pollutant fluxes of those rivers in 2009, and compared them with the literature data of previous years.Analyses showed that water fluxes of the inflow and outflow rivers were 88.40×10⁸m³ and 93.27×10⁸m³ successively in the year 2009, re-spectively.The 5 largest inflow water fluxes were in the order as Chendonggang >Dapugang >Liangxi River >Taige River >Wan-gyu River and the 2 largest outflow water fluxes were Taipu River and Changdougang.Analyses also showed that the river pollution from Yixing area were heaviest, and should be urgently improved.Also the outflow suspend particle fluxes were extremely larger than that of inflow and most of suspend particle was outflow in the south part of the lake.Furthermore, the total nitrogen and total phos-phorus fluxes increased since 2002.The project of water diversion from Yangtze River to Taihu basin was good for water quality of the lake.Comparison of water quality between the lake and rivers suggested that the inflow river pollutant had important effect on the lake water.

Abstract:In order to study the impact of the Three Gorges Project on concentration of total phosphorus(TP), TP concentration of five sections in Yangtze River within the Three Gorges Reservoir was monitored monthly between 1998 and 2009(impoundment be-gan in 2003).Results showed that there have appeared new characteristics in spatial and temporal distribution of TP concentration after impoundment.TP concentration of water column near the dam decreased significantly comparing with that before impound-ment.For example, the average TP concentration of Guandukou section and Taipingxi section in 2009 decreased by 42.8% and 54.9% than that before impoundment, respectively.TP concentration in wet season was still higher than that in even and dry sea-sons.Nearer the dam, smaller difference was observed between values in different seasons.After impoundment TP concentration declined from the tail to the head of the reservoir, and it decreased by 61%-65% from Qingxichang section(in the downstream of Fuling) to Taipingxi section(near the dam).The decrease was prominent especially in wet season.The reason for changes of TP concentration mentioned above was mainly due to sedimentation of sand in the reservoir, which resulted from water level increased and the velocity decreased.

Abstract:The concentrations and distribution of dissolved total phosphorus(DTP) and dissolved inorganic phosphorus(DIP) in the sediment interstitial water from Lake Poyang were determined based on the sampling in January 2010.The results showed that the average DTP and DIP concentrations in the overlying interstitial water of Lake Poyang (0-2 cm) were 0.134 mg/L and 0.082 mg/L, respectively, which showed no significant spatial variation between sampling sites.The profiles of DTP and DIP con-tents in the core sediment interstitial water increased with depth at 0-18 cm and then decreased with depth at 18-28 cm.For the DIP, no significant correlation was found between interstitial water and sediment.But for the DTP, a certain correlation existed be-tween the surface interstitial water and sediment, indicating that the concentration of TP in the surface sediment can influence the DTP content in the interstitial water.

Abstract:In order to understand the interactions between environmental factors and the algal biomass in Lake Chaohu, those rela-tively important environmental factors to alga biomass were extracted.Based on monitored water quality data of Lake Chaohu in 2008, cluster analysis, discriminate analysis and the recognition of pollution feature were carried out to reveal the relationships be-tween water environment factors and algal biomass.Results suggest that the Lake Chaohu can be divided into severe polluted area, moderately polluted area, and mildly polluted area from west to east.The Chl.a and dissolved total nitrogen are the indicative fac-tors describing the significantly spatial difference in water environment.The sequence of pollution classification for all the monito-ring sites are as follows:Nanfei river inlake area >Shiwuli river inlake area >Tangxi river inlake area >West lake center area >Paihe river inlake area >Hangbu river inlake area >Zhongmiao area >Zhaohe river inlake area >Bakou area >East lake center area >Ship factory >Zhonghan town area.The screened important environmental factors to algal biomass vary with seasons.TP, TN, temperature, NO₃^--N and NH₄⁺-N are closely related to algal biomass all the year round.

Abstract:Adopting the method of batch culture, the effect of ammonia nitrogen and nitrate nitrogen at different concentrations on the production of chlorophyll-a and microcystin of Microcystis sp.isolated from Yanghe Reservoir was investigated.Results showed that, when Microcystis sp.was cultured with ammonia nitrogen, contents of chlorophyll-a increased with ammonia nitrogen concen-tration in the logarithmic growth phase.However, the high concentration inhibited the growth of algae cells.The productions of MCRR fluctuated with the increase of ammonia nitrogen concentration.There was a remarkable rise of microcystin productions, reaching to 6.345×10^-8 μg/cell, when the concentration of ammonia nitrogen was 10.0 mg/L.This was significantly different with other treatments.When Microcystis sp.was cultured with nitrate nitrogen condition, contents of chlorophyll-a increased undu-lately with the increasing of nitrate nitrogen concentration, and there was no difference among different groups.The productions of microcystin under high concentration increased with the concentration during the logarithmic growth phase.They increased to 1.223×10^-8 μg/cell when the concentration was 5.0 mg/L, and reached the maximum value which was far less than that of the ammonia nitrogen group.There was no significant difference on the growth of algae between the two nitrogen sources.Ammonia ni-trogen was more beneficial to the synthesis of chlorophyll-a in algae cells with nitrogen concentration increasing under lower concen-tration(1.5-5.0 mg/L) during the logarithmic growth phase.The productions of microcystin under ammonia nitrogen condition were far larger than nitrate nitrogen group at the range of 1.0-10.0 mg/L, and there was significant difference among the groups.Overall, ammonia nitrogen was more easily to lead to the secretion of MCRR in algae cells.

Abstract:Comparisons have been done on the experiments about the transportation and sources of nitrogen in the hillsides within a single rainfall event in south China.Results indicate that the release of the nitrogen is represented by ammonia nitrogen and ni-trate nitrogen.Transportation of the total nitrogen, nitrate nitrogen and nitrous nitrogen is dominated by infiltration process, and that of the ammonia nitrogen is dominated by the surface migration.In the case of the urea release, the migration of the nitrogen is dominated by the dissolved form of urea, ammonia nitrogen and nitrate nitrogen.The total nitrogen, dissolved urea and ammonia nitrogen is characterized by the surface migration.The transportation of the nitrate nitrogen, nitrous nitrogen and organic nitrogen is dominated by the underground infiltration process.Without human interference, rainfall-induced nitrogen deposition has become one of the main sources of the nitrogen in the experiment field.

Abstract:The present study aims to develop a mathematical model for analyzing and predicting the hydrodynamic and water quality in one large lake (Lake Poyang) with great and rapid stage fluctuation, the complex topography and geometry, the complicated connectivity of narrow channels and depressions inside the lake, the frequently switch between exposed grass beach and water.Based on the two-dimensional shallow water equations and pollutant transport equations, the coupled two-dimensional hydrodynamic and pollutant transport model is developed.The unstructured finite volume method is applied to discretize the equations.The nor-mal water mass, momentum and pollutant fluxes are computed by the HLLC solver.The water front moving boundary is identified automatically by the judgment of the latest water stage.It makes the model be capable of simulating the complex flow regime and the dynamic of pollutant transport in the lake with drying and wetting processes.The hydrodynamic model is calibrated by the water regime of the year 1998.Based on the calibrated hydraulic parameters, the hydrodynamic and water quality (COD_Mn and ammo-nia) from January to October in 2008 are simulated by the proposed model.The time series data of measured water stage, COD_Mn and ammonia, and remotely water extent of CBERS data are both used to validate the results of computation in time and space.The results indicate that the model has the capability to model the flows dynamic and the pollutant transport in this kind of lake.

Abstract:The analyses of mineral assemblages of the core KS-2006 from Lake Kusai in the Hoh Xil area indicate that the carbon-ates in the sediments of Lake Kusai are mostly authigenic and mainly composed of aragonite.The variation of aragonite content probably reflects the temperature of lake water.Salt minerals were found since 2150 cal aBP, which is an indicative of the increase of salinity of lake water.Meanwhile, the increase of quartz content may be related to the enhancement of wind activity which is caused by the cold-dry climate in this area.The process of climatic and environmental evolutions of late Holocene in this area could be divided into 3 stages as follows:the climate was generally warm between 3770 cal aBP and 2550 cal aBP, then the temperature dropped slowly during 2550-2150 cal aBP;from 2150 cal aBP to present, the climate became cold and dry characterized by low temperature and high salinity of lake water, and strengthening of wind activity;however, there is a distinctly warm period occurred during 900-700 cal aBP.

Abstract:Holocene palaeo-flood slackwater deposits (SWD) were found in Yijun reaches of the Beiluohe River in the middle rea-ches of the Yellow River.They were identified by sedimentary criteria during fieldwork initially.A set of three beds of palaeo-flood SWD was interbedded in the Holocene loess-soil sequence within the cliff riverbanks.Each of the SWD represents one individual palaeo-flood event.The analytical results of grain-size distribution and magnetic susceptibility indicate that these SWD beds were deposited from the suspended sediment load in the floodwater.According to climatic and stratigraphic correlation with the OSL da-ted Holocene profiles in the region, these palaeo-flood events occurred during 8000-7800 aBP (SWD1), 6000-5000 aBP (SWD2) and 4200-4000 aBP(SWD3), respectively.The palaeo-flood peak discharges were calculated by hydrological models and estimated to between 13600 and 14100 m³/s.The archives of flood data were therefore extended to a time-scale of over 10000 years.A more reliable flood peak discharge and frequency relationship was established accurately.These results are very important in hydraulic engineering and mitigating flood hazard in Beiluohe River basin.These palaeo-floods are well correlated to the abrupt climatic events occurred during the mid-Holocene Climatic Optimum.They provide solid evidence for investigating the social im-pacts of per-historical floods on the decline of the Neolithic civilizations in China' s monsoon regions.

Abstract:The decomposition rate of cyanobacterial detritus and the release forms of nitrogen and phosphorus from the decomposing cyanobacterial detritus were investigated experimentally in this paper.Results showed that the content of total nitrogen of cyanobac-terial detritus was 88.56±4.10 mg/g;the decomposition rate of cyanobacterial detritus was high and there was 41.9% dry mass lost in two days.The release rate of total phosphorus of cyanobacterial detritus was faster than total nitrogen, but the increase in concentration of total dissolved nitrogen (TDN) in the water column lasted longer than total dissolved phosphorus (TDP) during the decomposing of cyanobacteria.After the increase in the first four days, the concentration of dissolved inorganic nitrogen (DIN) was kept constant but the concentration of dissolved organic nitrogen (DON) continued to increase.The ammonia was the main form of DIN in the water column, while the concentration of nitrate and nitrite was low during the decomposition.The Urea-N was not the main form of DON released by cyanobacterial detritus because the average percentage of Urea-N was low (3% of DON).The concentration of dissolved inorganic phosphorus (DIP) and dissolved organic phosphorus (DOP) increased in the first four days, and then DOP was transformed into DIP progressively.The present study demonstrated that the decomposition rate of cya-nobacterial detritus is high, with releasing of organic and inorganic nitrogen and phosphorus.The result of present study shed light on understanding of the impact of cyanobacterial blooms on nitrogen and phosphorus cycling of lakes.

Abstract:Crustacean zooplankton community in Lake Bosten was monitored and the impacts of environmental factors on curstacean zooplankton community structure were assessed during Jun.-Nov.2010 and Jan.2011.Results showed that crustacean zooplank-ton was mainly dominated by Cladocera, not only in species number, but also in density and biomass, with dominant species suc-ceeding seasonally.In summer, crustaceans were dominated by large-sized Daphnia cucullata and Diaphanosoma brachyurum.With the decrease of large-sized zooplankton in fall and winter, the percentage of small-sized Bosmina coregoni increased, sugges-ting that competition works between zooplankton of different body size.Regression analyses indicated that crustacean biomass and mean body length were positively correlated with water temperature.Correlation analyses revealed that the biomass of B.longirostris and D.cucullata was positively correlated with transparency, but negatively with Chl.a, indicating these two dominant species be-ing inhibited by the overgrowth of phytoplankton.Multivariate statistical analyses showed that 56.8% of the total variance in crus-tacean community structure was explained by environmental factors, with water temperature being the most important factor and wa-ter depth the second.High water temperature favoured the development of cyclopoids, D.cucullata and D.brachyurum.Mean-while, B.coregoni preferred to flourish in shallow stations while D.cucullata and D.brachyurum in deep stations.The difference in distribution pattern of dominant species might be due to the fish predation.

Abstract:To investigate the response of planktonic bacterial abundance to lake eutrophication and salinization in drought zones, water samples of 23 stations in Lake Bosten were collected in June, 2010.The DAPI-combined epifluorescence direct counting method (DAPI-FDC) was used to identify the spatial distribution pattern of planktonic bacterial abundance and the relationship with the environmental parameters.The results showed that the epilimnetic total nitrogen (TN) concentration in Lake Bosten was ranged 0.26-1.45 mg/L (mean=0.91 mg/L), indicating a mesotrophic and eutrophic level.The concentration of total dissolved solids (TDS) varied from 219 mg/L to 1696 mg/L (mean=1125 mg/L), which indicated that Lake Bosten is a brackish lake now.The abundance of planktonic bacteria was ranged (1.41-4.57)×10⁶ cells/ml (mean=2.89×10⁶ cells/ml), with the higher values appeared in station 5 and other heavily polluted northwest lake regions, and the lowest value appeared in the station 14 located in the estuary.Cluster analysis showed that the 23 sampling stations can be divided into two groups:freshwater region (FR) and brackish lake region (BLR).Compared with freshwater region, the concentrations of TDS, electrical conductivity, salinity, COD_Mn, chloride and sulfate in brackish lake region were significantly higher.The bacterial abundance was significantly positive correlated with COD_Mn and Cl^-.In summary, the spatial distribution pattern of bacterial abundance was a response to different levels of nutrients and salinity in Lake Bosten.Hence the abundance of bacteria was a sensitive indicator reflecting the eutrophication and salinization.

Abstract:Submersed macrophyte, Potamogeton crispus, was planted in water at depth of 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5 and 4.0 m in pots, with the aim to study the influence of the water depths on plant adaptability in reproduction, biomass allocation and photosynthetic properties and to elicit the way of energy distribution when they are in different water depths.Results showed that the stem length of P.crispus had an evident correlation with water depth and the appropriate water depth for P.crispus growth was 0.5-2.5 m.At the depth of 0.5 and 1.5 m, Potamogeton crispus turion has the largest clones and highest biomass, and the tallest stem length, respectively.Water depth gradients do not affect the germination of P.crispus turions with germination rates > 70% from deep water 0.5 m to 4 m in the experimental group.The adaptability of P.crispus to different water depths has a strong phenotypic plasticity.Height and biomass vary with different water depths for P.crispus.With the increase of water depth and the decrease of light intensity, P.crispus distributes more energy to the growth of plant height so that it can get more luminous energy, which leads to the gradually reduction of energy to reproductive organs and eventually to a balance of energy distribution.The phe-notypic plasticity can adapt to different light stress and what' s more, it can also change the content of the chlorophyll to further re-spond to different light under stress.Below the depth of 3.0 m, the chlorophyll of P.crispus greatly increased to use of energy effi-ciently, which is illustrated by the comparable light response capacity of the experimental group from 3.0-4.0 m and is still not lower than other groups.

Abstract:Monthly algae samples in Hulanhe Wetland, Heilongjiang Province, were collected from May to October, 2009.A total of 158 taxa, belonging to 7 phyla, 8 classes, 14 orders, 23 families, 50 genera, 148 species and 10 varieties, were identified.The abundance of algae ranged from 469.55×10⁵-847.35×10⁵ cells/L.They were predominantly Bacillariophyta and Chlorophy-ta.The composition and biomass of the algae varied with the studying periods.Most of the algae were found in the site II.While the biomass in sites I and V was greater than that of other sites.Results showed that most taxa were common species and several in-dicator species for eutrophication and pollution were also found.According to the assessments using saprobic indicator, Shannon-Wiener diversity index and Pielou evenness index, the water in Hulanhe Wetland was of different degrees of pollution.

Abstract:Callus of Alternanthera philoxeroides, as experimental material, was cultured by tissue culture technique.In this study, the calluses were subjected to different concentrations of Cr⁶⁺ (0, 0.1, 0.3, 0.6 and 0.9 mmol/L) and the impacts on contents of putrescine (Put), spermidine (Spd), spermine (Spm)and proline(Pro), activities of arginine decarboxylase (ADC), orni-thine decarboxylase(ODC), polyamine oxidase(PAO) and Diamine Oxidase(DAO) were investigated.Results indicated that, with the increasing of Cr⁶⁺ concentration, (1) the contents of three free PAs increased at first and then decreased, and reached their peak values at 0.6 mmol/L Cr⁶⁺ treatments;(2) the content of PS-conjugated Put reached its peak value at 0.1 mmol/L Cr⁶⁺ treatment and then decreased slowly, while the contents of PS-conjugated spermidine (Spd) and spermine (Spm) increased significantly;(3) the peak values of PIS-conjugated Put and Spd were present at 0.6 mmol/L Cr⁶⁺ treatment;meantime the peak value of PIS-conjugated Spm was present at 0.1 mmol/L Cr⁶⁺ treatment;(4)the activities of ADC and ODC increased gradually, while PAO and DAO activities decreased sharply after a transient increase;(5) the level of Pro increased at 0.1-0.3 mmol/L Cr⁶⁺ treatments and decreased at 0.6-0.9 mmol/L Cr⁶⁺ treatments.These results suggested that Cr⁶⁺ stress disturbed metabolic balance of polyamines and increased the level of PAs.Obviously, the changes of PAs levels might be essential to Cr⁶⁺ adaption of cells.

Abstract:The species composition, spatial and temporal distribution of shrimps in the Gonghu Bay (Lake Taihu) were investiga-ted by sampling with pop-net in April, July and October of 2005.The total of 9605 individuals belonging to 5 species, 3 genera and 2 families were collected.The relative percentage of Exopalaemon modestus, Caridina nilotica gracilipes, Neocaridina denticulata sinensis, Macrobrachium nipponense to the tota1 is 63.79%, 13.93%, 12.69% and 9.46%, respectively.Based on the type and coverage of aquatic vegetation, the lake was categorized into 5 habitat types:Potamogeton maackianus habitat, mixed sub-merged macrophyte habitat, Potamogeton malaianus habitat, littoral zone with a little macrophyte habitat, and naked habitat.The density sequence of all shrimps from high to low is Potamogeton maackianus habitat, mixed submerged macrophyte habitat, Potamogeton malaianus habitat, littoral zone with a little macrophyte habitat and naked habitat.The biomass of shrimps decreased substantially in Potamogeton maackianus habitat, Potamogeton malaianus habitat, combined submerged macrophyte habitat, littoral zone with a little macrophyte habitat, and naked habitat.Each of the dominant species preferred the Potamogeton maackianus habi-tat.In terms of seasonal variation, both the largest density and biomass of the dominant shrimps were in summer (July), followed by spring (April) and autumn (October).

Abstract:Based on the historic data of fish catches and an investigation on fish assemblage from 2009 to 2010 in Lake Taihu, the dynamic variation of fishery resources and their responses to water eutrophication were analyzed.Results showed that only 47 spe-cies (belonging to 37 genera, 14 families and 10 orders) were recorded in Lake Taihu, the common species of fish were decreased and the fishes of Cyprinidae became the major community.The total fishery yield in the lake had increased rapidly in recent years, and the percentage of small fishes, such as Coilia ectenes taihuensis, had increased in fish catches;however, the percentage of oth-er large fishes, such as Culter alburnus, had decreased rapidly.Because of water eutrophication and imbalance of the fishery struc-ture, the tendency of smaller-scale fishery was more obvious.Compared with fishery resources of the eastern lake area, northern lake area and center area of Lake Taihu, the results showed that Coilia ectenes taihuensis had become the dominant specie in the northern lake area and center area, with the percentage of its fish catches reaching 70.7% and 80.4%, respectively.But the per-centage of carnivorous fishes and herbivorous fishes was relatively high in the eastern lake area.Such obvious differences among the compositions of catches in different lake regions reflected the influence of environmental factors on the compositions of fish catches.Based on the relationship between water eutrophication and fishery of Lake Taihu, some strategies were suggested, such as strength-ening the studies on relation of fishery and water environment and paying attention to the effect of aquatic plants on sustainable de-velopment of fishery.

Abstract:Lake Ulungur is the second largest lake of Xinjiang Uigur Autonomous Region and one of the ten largest freshwater lakes in China.With the impact of human activities and climate variation, nutrients and biotic communities in the lake have been changed obviously.To understand the community of benthic macroinvertebrates and its response to the changes in their environ-ment, we surveyed the benthic macroinvertebrates community in Lake Ulungur seasonally from Nov.2006 to July 2008.In total, 87 taxa were recorded, including 61 Insecta (70.1%), 14 Oligochaeta (16.2%), 7 Mollusca (8.0%) and other 5 taxa (5.7%).The annual density and biomass averaged 1015.01 ind./m² and 9.83 g/m², respectively.The density was highest in winter(1234.96 ind./m²), followed by spring (1044.47 ind./m²) and autumn(931.16 ind./m²), and lowest in summer (849.44 ind./m²).The biomass of benthic macroinvertebrates was highest in winter(13.54 g/m²), followed by spring(12.01 g/m²) and autumn(8.37 g/m²), and lowest in summer(5.02 g/m²).The annual average value of Shannon-Wiener diversity index and Margalef diversity index was 2.19 and 1.34, respectively.Correlation analyses indicated that water depth was the key factor influ-encing the standing crops of the benthic macroinvertebrates in this lake.

Abstract:In order to evaluate fish resource status in Zhihugang, gate-controlled inflow river of Lake Taihu, fish assemblage status in Longyanhe river system, main tributary of Zhihugang and their influencing factors were studied in August 2009 and May 2010 re-spectively.Results showed that a wide variety of fish species existed in the study area, and thirty two species of fish were collected, which belong to 22 genera, 27 families and 5 orders.Species numbers of fish assemblages in spring and summer had not obvious difference;however, fish abundance and biomass in spring were both significantly higher than those in summer;species composi-tion of fish assemblages in different locations, that is, main tributary, secondary tributary and tributary end, varied as well.Water transparency and dissolved oxygen content were positively correlated with abundances of Carassius auratus, Macropodus ocellatus and Macropodus opercularis, Water nutrient concentrations, i.e., nitrogen and phosphorus, were negatively related to fish abun-dances of Pseudobrama simoni, Hemicculter leuciclus and Carassius auratus.Excess nutrient concentration and corresponding low water transparency and dissolved oxygen content produced an adverse effect on fish assemblage structure and species composition.

Abstract:With the hydrological model SWAT, the runoff variation of three representative watersheds in Dongjiang River Basin was simulated.With discharge data from Shengqian, Shuntian and Jiuzhou hydrological stations in 1977-1981 and 1996-2000, more sensitive hydrology factors were calibrated and satisfactory simulation results were obtained (R²>0.85, 0.68 <E_NS <0.75).The study investigated the influences of LUCC on the hydrological process of the three watersheds.The result shows that:(1) the in-crease of forest area was the cause of annual runoff decrease;(2) in terms of annual variability, runoff decrease in the wet season while increase in the dry season;(3) the decrease of runoff becomes more notable when the forest area increases with slope <15°.