Abstract:The mechanism of the decline of aquatic macrophytes in eutrophic waters has recently become a central and growing in-terest to aquatic ecologists.Here,we described the biomechanical properties of aquatic macrophytes,their responses to eutrophica-tion and their possible contribution to the decline caused by eutrophication.Different from most terrestrial plants,the biomechanical properties of aquatic macrophytes mainly included the tensile properties of stems/leaves/petioles (the bending properties of stems/petioles for emergent macrophytes) and root anchorage strength.Three vital factors of eutrophication,the fertile sediment,higher concentrations of nitrogen and phosphorus in water-column and limited light availability,had significantly negative and species-spe-cific influences on the biomechanical properties of aquatic macrophytes.Additionally,there were strong relationships between the biomechanical properties and the other aspects,which were also significantly affected on,such as plant growth,morphology,bio-mass allocation,anatomic structure and metabolism,as well as collaboration between these factors during their response to the eu-trophication.What's more,the mechanical damages interrupted the life progress because of a vital reduce in resource acquisition for parent plants and a relative low spreading and colonize ability for all fragments,resulting in a low fitness.Numerous field investigations and laboratory experiments can imply that the changed biomechanical properties do play a key role in the decline of aquatic macrophytes during the progress of eutrophication.As the multiple interactions among the environmental factors existed in natural waters,most studies only focused on the effects of the three vital factors resulted from eutrophication on the biomechanical proper-ties of aquatic macrophytes.Therefore,further and systematical studies should be conducted on the plant biomechanical properties responding to multiply factors (dissolved oxygen,algal toxins and herbivores) because these factors also have significant effects during eutrophication.Thus the biomechanical mechanism for the decline of aquatic macrophytes in eutrophic waters can be well re-vealed.

Abstract:Himawari-8 as a new generation geostationary meteorological satellite can provide the observation data for dynamically monitoring of Cyanobacteria bloom,with high time resolution at an interval per 10 minutes.According to the spectrum measuring data of Lake Taihu area,a method using the Himawari-8 data was proposed for dynamically monitoring of the Cyanobacteria bloom.In this paper,the outbreak processes of Cyanobacteria bloom on October 2nd,2015 were monitored continuously including the Cya-nobacteria bloom's appearing,increasing and disappearing.The dynamic changes of the intensity and speed of Cyanobacteria bloom were calculated,and the extent and variation were analyzed.All the analysis provided useful information for studying the growth and death of Cyanobacteria bloom.Furthermore,this paper discussed the relation between Cyanobacteria bloom's dynamic changes and meteorological elements of temperature and humidity under the same conditions.Results showed that wind is a direct driving effect on appearing,increasing and disappearing of the Cyanobacteria blooms.

Abstract:This study attempts to explore the physiological responses of Peridiniopsis bloom to phosphorus concentrations in Xiangxi River Bay of Three Gorges Reservoir.The population dynamics of phytoplankton and some environmental factors of waterbody were investigated on 9 sampling sites in the Xiangxi River Bay during water bloom period in spring of 2015.A strain of Peridiniopsis was isolated and purified from Xiangxi River.Specific growth rates of Peridiniopsis were measured at 5 different concentrations (0,0.005,0.020,0.100 and 0.600 mg/L) of phosphorus culture medium.Rapid light curves,photosynthetic oxygen evolution vs.in-organic carbon concentration curves and their parameters were examined at logarithmic growth phase.Results show that the high cell density of Peridiniopsis may indicate a high total phosphorus concentration.The conditions of high phosphorus could enhance photo-synthetic efficiency of Peridiniopsis,stimulate its growth,and increase its affinity for inorganic carbon.Therefore,high phosphorus content in water environment may be one of the key factors to promote the outbreak of dinoflagellate Peridiniopsis blooms.

Abstract:In order to improve water quality of Lake Dianchi,the characteristics of non-point source pollution from flower green-house area along the east bank of the Lake Dianchi were explored.The Storm Water Management Model (SWMM) was built with measured rainfall runoff data to simulate the quantity and quality of rainfall runoff under both continuous and typical rainfall condi-tions in a flower greenhouse area in Dounan Village,Chenggong County.The results indicate that:1) The Nash-Sutcliffe efficiency coefficients of the flow,chemical oxygen demand (COD_Cr),suspended solids (SS),total nitrogen (TN) and total phosphorus (TP) in the SWMM are 0.858,0.835,0.803,0.712 and 0.752,respectively,so that the SWMM model can be used to predict the quantity and quality of rainfall runoff in the area.2) The average runoff coefficient of the area is 0.59.The annual loads per unit area of COD_Cr,SS,TN and TP are 118.34,82.90,54.64 and 5.46 kg/(ha·a),respectively.TN and TP are major pollutants.3) The peaks of every pollutant concentrations appeared earlier than the flow peak so controlling the pollutant load should be ad-vanced,especially for TN and TP controlling.

Abstract:Numerical eutrophication model is an important tool to predict and manage the ecosystem of lakes and reservoirs.Howev-er,the objective errors of the model are always vital problems the users concerned.Data assimilation,which connects observations and model simulations,can effectively improve the accuracy of models.Ensemble Kalman filter (EnKF),which is one of the most widely used methods for data assimilation,is suitable for nonlinear system and has high computation efficiency.In this research,the Delft3D-BLOOM was taken as the eutrophication model,and Lake Taihu was taken as the study case.After numerical testing,the ensemble size was set to 100,the observation error variance was set to 1%,and the simulation error variance was set to 10%.Two data assimilation modes,assimilation of model state variables and synchronous assimilation of both state variables and key pa-rameters,were examined.The results showed that the fitness between model simulation and observation was slightly improved when the state variable was updated.When both the state variables and parameters were assimilated,the fitness was significantly im-proved.The study provides a promising approach in using EnKF to improve the simulation accuracy of complex eutrophication mod-els.

Abstract:To investigate the effect of step feeding on the performance of multi-stage vertical flow constructed wetland (MS-VFCW) for municipal wastewater treatment,raw wastewater with four step feeding ratios (0%,10%,20% and 30%) were dosed to the second stage of the MS-VFCW plots at a total hydraulic load of 100 mm/d.The results showed no significant differences in removal of chemical oxygen demand (COD) and total phosphorus (TP) among the four step feeding ratios,and the highest removal rates of COD and TP reached up to 87.80% and 81.17%,respectively.Most COD was removed in the first stage,with an average contribu-tion of 82.18%.While the most TP was removed in the third stage,with an average contribution of 54.37%.In contrast,the differ-ences in total nitrogen (TN) removal rates among the four step feeding ratios were significant,with the highest TN removal rates (61.70%±4.48%) under the ratio of 20%,in which the average removal contribution of each stage was 36.52%,42.11% and 21.37%,respectively.The step feeding ratio was recommended as 20% in application of the hybrid VFCWs so as to achieve sound pollutant removal performance.

Abstract:This study investigated 37 lakes of the Jianghan lake group in the middle reach of the Yangtze River.Trophic state index (TSI) was applied to define the trophic status of the lakes.According to water quality,sediment quality and aquatic biological communities,the analytic hierarchy process (AHP) and entropy weight method combined with fuzzy comprehensive evaluation based on fuzzy mathematics methods were applied to evaluate the aquatic ecosystem health.The lakes trophic evaluation showed that Lake Haikou was in the mesotrophic status,18 lakes were in eutrophic status,and 18 lakes were in hyper-eutrophic status.The as-sessment of lake ecosystem health turned out that only Lake Haikou was in the "high" health status.Five lakes were in "good" health status:Lakes Dongxicha,Huama,Liangzi,Tongjia and Zhangdu.The rest 31 lakes were all in "poor" health status.Ac-cording to the TSI,for the ecosystem health assessment of the Jianghan lake group,AHP combined with fuzzy comprehensive evalu-ation was proved to be a better method than the entropy weighting method.

Abstract:It is universally accepted that the coupling relationship between phosphorus (P) and iron (Fe) is responsible for the migration of P,but there is little direct in situ evidence.In order to investigate the coupling relationship between P and Fe in sedi-ments of shallow lakes,the concentrations of labile P and Fe in the sediments in Lakes Taihu,Chaohu,Poyang and Dongting were measured using ZrO-Chelex diffusive gradients in thin films (ZrO-Chelex DGT).The results showed that both labile Fe and P be-gan to increase downward below the sediment-water surface followed by fluctuation up to the bottom of the sediment profiles.Their changes were consistent along the profiles,which were further supported by the positively linear correlations among them.Anaerobic incubation experiment further showed that the reductive dissolution of iron oxides led to the releases of ferrous Fe and P associated with iron oxides.The results proved that the remobilization of P in sediments was dominated by Fe redox.

Abstract:Water quality potential factor and chromophoric dissolved organic matter fluorescence in Lake Ebinur and its major in-flow tributaries were analyzed.Results indicated that three dimensional fluorescence spectra (EEM) of Jinghe River and Bortala River showed that all sampled water bodies contained C1(260/420 nm) humic organic matter,C2(240,240/490 nm) and C4(260,270/530 nm) kind of humus,and C3(220/280,300/450 nm) protein like,which was based on PARAFAC analysis meth-od.In order to further understand the characteristics of DOM components,it was found that protein organic matter was the highest and fulvic acid was the lowest in Jinghe River and Bortala River,based on FRI analysis and the regional standards related to water quality and fluorescence.Among the correlation coefficients of water quality parameters and fluorescence indexes,biological index (BIX) and total nitrogen (TN) concentration,humification index (HIX) and ammonium nitrogen (NH₄⁺-N) were high in Lake Ebinur's major inflow tributaries:the correlation coefficients were 0.831 and 0.684,at P<0.01 significant level,respectively.Cor-relation between HIX and TN concentration was 0.604 at P<0.05 significant level.The water quality parameters and the fluores-cence indexes showed a three fitting relationships,while the HIX-NH₄⁺-N fitting effect is best with the correlation coefficient of 0.908.The second one is the BIX-TN with the correlation coefficient of 0.844.The results of this work can provide scientific support for the water quality management and restoration in this area.

Abstract:Contents of Al,Fe,Mn,Zn,Cr,Co,Ni,Cu,As,Cd and Pb in the surface and core sediments of Lake Yangzonghai were determined.Combined with geochronology,the heavy metal spatio-temporal characteristics,the status relative to the pre-in-dustrial levels,and potential ecological risk of the pollution were evaluated by the surface and core sediments from Lake Yangzong-hai.The results showed that metal contents exhibited obviously spatial variations in the surface sediments.Contents of As,Cd,Cu,Pb and Zn were generally higher in the middle-east lake area than those in other areas.In contrast,contents of Cr,Co and Ni showed higher values in the south lake area.Contents of As,Cd,Cu,Pb and Zn in the core sediment had increased gradually since the mid^-1990s and reached the maximum values around the year of 2009-2010,followed by a gradual decline in recent years.Contents of Cr,Co and Ni showed similar temporal variations to the trends of detrital metals (such as Al and Fe),and they decreased generally in recent hundred years.As,Cd,Cu,Pb and Zn in sediments of Lake Yangzonghai were contaminated as indi-cated by the enrichment coefficients,showing that metal contaminations began at the mid^-1990s and reached the maximum values around the year of 2009-2010,but it declined gradually in recent years with the implementation of industrial discharge control.In the surface sediments,Cu was at unpolluted to minimal contamination levels,while Zn and Pb displayed minimal to moderate con-tamination levels.Metal As had moderate to strong contamination levels,and Cd showed minimal to strong contamination levels.The pollution levels of the metals in the eastern lake were higher than those in other lake areas,these are because of a relatively rare runoff,low deposition of detrital materials and high anthropogenic/detrital metal sedimentation.The metals in sediment of Lake Yangzonghai may pose a medium to strong potential ecological risk when compared with a historical pollution peak around 2002-2010.The main contribution factors were Cd and As.Potential eco-risks of the metals decreased in recent years and reduced to the low level except in the east lake area,where the metals may be of a moderate potential ecological risk.

Abstract:Atmospheric deposition is one of the important pathways for nitrogen (N) and phosphorus (P) transported into lakes.To understand the potential impact of N and P from atmospheric depositions on the eutrophication of Lake Yangzonghai,this re-search investigated the temporal variation and estimated the fluxes of N and P from atmospheric depositions in the lake catchment.The sources and impact factors of the N and P depositions were analyzed by monitoring data from May 2012 to April 2014.Since Lake Yangzonghai is a P-limited lake,this study especially compared the P fluxes from N and P atmospheric deposition with that from non-point sources,and assessed the potential P-impact from atmospheric deposition on the eutrophication lake.The results showed that the average annual deposition flux of total nitrogen was 248 mg/m²,and seasonal deposition fluxes in spring,summer,autumn and winter were 200,306,274 and 214 mg/m²,respectively.The peak of N flux occurred in summer because of the in-creased rainfall.The annual average P deposition flux was 24 mg/m²,and seasonal deposition fluxes in spring,summer,autumn and winter were 18,31,19 and 27 mg/m²,respectively.Compared with the non-point P-load source,P-input from atmospheric deposition seemed very small,and would have little effect on the eutrophication of the lake.

Abstract:Spatio-temporal characteristics and source identification of water pollutants are important for the management and protec-tion of water resources.In this study,water-quality index (WQI) modeling,hierarchical cluster analysis,discriminant analysis,factor analysis and principle analysis of multiply linear regression (APCS-MLR) were used to analyze the water quality data sets from river network during 2015,including 10 parameters monitored at 54 different sites in Lake Ebinur Watershed of Xinjiang.U-sing GIS to study the spatio-temporal characteristics and source identification of surface water pollutants were the major goals of this study.The results showed that:The value of WQI varies between 38 and 70 during wet season when the water levels were high,while the value was between 31 and 71 during dry season.The Lake Ebinur water quality deterioration was more significant during wet season,and the water pollution status at Lake Ebinur,Bortala River and Jinghe River near Lake Ebinur were more serious than other tributaries.By cluster analysis and discriminant analysis,the basin could be divided into two groups.The group A included the eastern area of Lake Ebinur,Kuitun River,Guertu River and Sikeshu River.The group B included the western area of Lake Ebinur,Jinghe River and Bortala River.Water quality at the B group of Lake Ebinur Watershed was mainly influenced by chemical oxygen demand,dissolved oxygen,ammonia nitrogen and suspended solids concentrations during the dry season,more serious than the group A because there are some high polluting enterprises at the group B region,while the water environment governance mainly cancentrated in the B region.In Lake Ebinur,Jinghe River and Bortala River,water pollutants mainly came from organic and nutri-ent pollution,followed by mining and industrial pollution.In Kuitun River,Guertu Rive and Sikeshu River,surface water pollu-tants mainly came from organic and biological pollution,followed by nutrient pollution,while biological pollution effects were rela-tively weak.Results of the water quality study would provide valuable and useful information for the future management of water re-sources in Lake Ebinur.

Abstract:In order to research the interaction of water sources and dissolved solids in surface water and groundwater in the Linhuan coal mining subsidence area,81 water samples were collected from surface water and groundwater during the periods of wet period,median water period,and dry period.The concentrations,compositions and types of major ions were analyzed.The influence factors were discussed by Piper graph,Gibbs graph and the method of factor analysis.The results indicate that:Total dissolved solids (TDS) are in the order of dry season > wet season > median water period in surface water,and in the order of dry period > median water period > wet period in groundwater.The TDS of surface water are obviously higher than those of groundwater.Na⁺,Cl^-and SO₄^2- are major ions in surface water,and mainly belong to the water chemistry type of SO₄^2--Cl^--Na⁺.HCO₃^-,Ca²⁺ and Mg²⁺ are major ions in groundwater,and belong to the water chemistry type of HCO₃^--Ca²⁺-Mg²⁺.The Gibbs graph and factor analysis show that intense evaporation process,surface runoff and mining activities occurred in the surface water.To a certain extent,shallow groundwater reflects the characteristics of atmospheric precipitation and recharges of surface water,which is mainly influenced by rock weathering degrees.

Abstract:Inhibition effect of different ultrasonic intensities was investigated by using Microcystis colonies from Lake Taihu,and the aim of this study was to obtain the optimal ultrasound parameters.The floating character of Microcystis colonies after sonication was cultured under different illumination intensity and temperature conditions.Results showed that sonication for 60 s at 0.0353 W/cm³ was an optimal parameter,which led to an immediate sedimentation (up to 80%) markedly.In the experiment,the algal cell con-centration and chlorophyll-a concentration were unchanged,which suggested that algal cells remained intact and cell inclusions did not leak to contaminate water quality.Light and temperature played important roles in the floating process of Microcystis colonies,but light was a more significant factor during the process.Under 2000 lx at 25℃,the floating rate of algal cells could restore to the normal level after 120 h,while the floating rate of algal cells after sonication did not change significantly at a relatively low temper-ature (≤ 20℃).In comparison,at a higher temperature of 25℃,the floating rate increased after 72 h which could restore to 80% of the level in control group after 120 h.Therefore,the ultrasonic control of algal blooms in lakes should choose a weak illumination intensity and low temperature condition.

Abstract:Physiochemical conditions and macrozoobenthos in Lake Luoma were investigated monthly in 2014.The lake was divided into three regions of the sand mining,the vegetation and the others according to its habitat conditions.Physiochemical parameters and macrozoobenthic community structure were compared among the three regions.Water quality was evaluated based on the surface water environmental quality standard (GB 3838-2002),comprehensive trophic level index and biological indices.The depth of sand mining area was significantly higher than that in the vegetation area,while the transparency was much lower than the other two regions.The concentrations of total nitrogen,total phosphorus,nitrate and phosphate in the sand mining area were significantly higher than those in the vegetation area,while the biodiversity indices of macrozoobenthos were significantly lower than the other two regions.A total of 41 taxa were identified,including 8 species of Annelida,15 species of Mollusca and 18 species of Arthropo-da.Bellamya aeruginosa,Branchiura sowerbyi,Limnodrilus hoffmeister and Alocinma longicornis dominated the community with high abundance and biomass.The annual average density and biomass of macrozoobenthos were 77.19±43.59 ind./m² and 37.62±28.31 g/m²,respectively.Higher spatial heterogeneity was observed for the mean biomass than the mean density.The relative high mean biomass values were found in the littoral sampling sites while the relative low values in offshore sampling sites.It showed that the lake was moderately polluted at a mesotrophic level.As an important water source and aquaculture site,more attention should be paid on water environment protection in Lake Luoma.

Abstract:Food quality can influence the growth and reproduction of zooplankton in freshwater systems.Food size,element ratios,biochemical composition and toxicity are indicative of food quality.The C/P ratios of Scenedesmus obliquus was used to represent the food quality in this experiment.We analyzed the effects of S.obliquus with different C/P ratios on the growth and reproduction of Daphnia similis.The C/P ratios of S.obliquus in four treatments were 881.8,512.3,124.3 and 42.4,respectively.The growth rates of D.similis in four treatments were 0.15,0.27,0.47 and 0.44 d^-1,respectively. D.similis did not release any offspring dur-ing this period of growth in treatment with C/P=881.8.The average numbers of offspring of first adult instar of D.similis in other three treatments were 1.2±1.3,9.8±2.3 and 9.5±2.5 ind./female,respectively.The results showed that the growth rate and off-spring number of D.similis decreased when the C/P ratio of S.obliquus was too high (512.3 and 881.8) or too low (42.4) com-pared with C/P=124.3.Our study indicated that different C/P ratios of food could affect the growth and reproduction of Daphnia,thus determining their survival in freshwater lakes.

Abstract:From June,2013 to June,2015,an investigation of bird communities had been made in habitats of farmland,river wet-land and lake wetland in Yingzhou West Lake Reserve.A total of 123 species were recorded,which belong to 14 orders,33 fami-lies and 69 genera.We analyzed the relative diversity indices.Results showed that the species number and density in autumn were higher than those in other seasons.The Shannon-Wiener index and Pielou index in summer were the highest.The species number in lake wetland was the greatest among the three habitats.The density,Shannon-Wiener index and Pielou index in lake wetland and farmland were higher than those in river wetland.At the same time,the dominance index in river wetland was the highest.In terms of diversities at family and genus,the G-F index in Yingzhou West Lake Reserve was 0.76.Yingzhou West Lake Reserve is an im-portant stopover and wintering site for shorebirds and Anatidae birds.

Abstract:Many notorious alien invader are clonal plants,thus it is of great significance to understand the effect of clonal integra-tion on their potential invasiveness.This study investigated clonal integration (stolon connection) on the photosynthetic perform-ance,growth,competitive ability and biomass allocation of Alternanthera philoxeroides when it invaded the native Ludwigia pep-loides plant population,to explore the contribution of clonal integration on the invasion of this plant.We found that plant competi-tion significantly reduced the maximum quantum yield of photosystem Ⅱ,final biomass,ramet number and total stolon length of A.philoxeroides,whereas clonal integration greatly improved the photosynthetic performance,growth measures,significantly increased the competitive ability and root/shoot ratios of A.philoxeroides and facilitated its invasiveness.

Abstract:The dormant egg bank in sediments has been regarded as a pool of species diversity and genetic information of freshwater Cladocera.Hatchings from the sediments strongly and directly affect the abundance and genetic structure of active population of Cladocera.In the present study,we sampled the active population in water column and picked up dormant eggs of Daphnia galeata in the top 10 cm of the sediment in Liuxihe Reservoir.We used cytochrome C oxidase subunit I gene to reveal the haplotype diversi-ty and genetic differentiation of active and dormant populations of Daphnia galeata in the reservoir.Our results showed the dormant population had higher haplotype diversity and nucleotide diversity than the active population.The haplotype diversity and nucleotide diversity were 0.562 and 0.00104 for the initial active population,0.726 and 0.00331 for the end active population,and 0.815 and 0.00761 for the dormant population,respectively.The coalescent calculation suggested that there was a bi-directional gene flow be-tween the active and dormant populations:the effective migration rate was 490.9 from active population to dormant population and 527.5 from dormant population to active population.We did not find hidden or subspecies differentiation in the dormant population and the active population by means of a Bayesian system tree.No significant genetic differentiation between the dormant population and the active population suggested that the genetic diversity of the active population was contributed by the dormant population.Therefore,the dormant population reflects the total genetic diversity of populations in the reservoir.The gene flow between the dor-mant and active populations was related to the hatching of dormant eggs rather than the size of the dormant eggs.

Abstract:The flood and low stage adjustments in downstream reach of reservoir projects have an important effect on water security,water ecology and water resource utilization.The variation features of the water stages are studied in the middle Yangtze River after impoundment of the TGR,based on the hydrological data via one improved method of the time series analysis.The results and con-clusions are as follows:The low water stage exhibited a decreasing trend due to its periodic time increased from 9-14 years to more than 20 years,while the flood stage had no decreasing trend because its change amplitude was less than the max value in history.The main reason for low stage decline is that the erosion amounts in low flow channel increased year by year,when its proportion accounted for the proportion of bank-full channel even reached at 91.5% in 2013.The river resistance has led to flood stage rising which increased by sand coarsening,vegetation coverage in beach above bank-full stage,and other projects such as navigation reg-ulation,revetment,and wharf etc.Change in the water stages is harmful to the improvement of channel depth and the water storage in the reservoir,although the flow discharge compensation of reservoir improves the low flow stage.The water-storage capacities of lakes have no change because the flood stage is not significantly decreased.

Abstract:Backflow is an important mechanism controlling flow and transport in many connected river-lake systems.This study used statistical methods and hydrodynamic-particle tracking models to examine primary causal factors of backflow,indication of backflow occurrence and influences of backflow on the hydrodynamics in a large floodplain lake (Poyang Lake,China).Statistical analysis indicates that although both catchment inflows and the Yangtze River discharge are all the influencing factors of backflow,the Yangtze River discharge is the main controlling factor of backflow during July and October,rather than catchment inflows to the lake.The ratio of Poyang Basin inflows to Yangtze River discharge can be used as an indication of the daily occurrence of backflow,which is most likely to occur during periods when this ratio is lower than 5%.If this ratio is higher than 10%,the probability of backflow occurrence is lower than 2%.Hydrodynamic modeling reveals that,in general,backflow causes an increasing in lake wa-ter levels ranging from 0.2 to 1.5 m,and tends to increase the magnitude of the water velocities (by up to 0.3 m/s) in the lake's main flow channels.Backflow disturbs the normal northward water flow direction in range of 90°-180° across Poyang Lake,and transports mass varied from a few kilometers to approximately 20 km southward into the lake.Backflow tends to increase the magni-tudes of the water velocities and water levels in the lake's main flow channels more than in the shallow floodplain areas.The influ-ence of backflow on the hydrological regimes in Poyang Lake attenuates with distance from the Yangtze River,as expected,but nonetheless propagates to virtually its upstream extremity.

Abstract:Obtaining the spatial distribution of free water storage capacity is a significant matter for distributed hydrological model.In this paper,the free water storage capacity,a parameter that has a significant effect on the simulation results of model,was se-lected as a research object.We have established the function relationship between topographic index and free water storage capacity to get the spatial distribution of free water storage capacity.And then this method has been applied in Chenhe Catchment which is located in Shanxi Province.Its spatial distribution of free water storage capacity could be derived by the method.A distributed mod-el,Grid-Xin'anjiang model,is obtained based on the spatial distribution of free water storage capacity.Application of the model to the Chenhe Catchment in Shanxi Province shows that this method is effective.This method,based on the laws of physic,can calcu-late the spatial distribution of free water storage capacity with higher accuracy.Thus,it provides a solid basis for development of a distributed model.

Abstract:Lake Qinghai,the biggest inland lake and biggest saltwater lake in China,lies in the north-eastern part of the Qinghai Tibet Plateau.The lake is also an important vapour source for the special region.The dynamic variation of its water surface is a re-sponse of climate and environment around.In this study the long-time variation of Lake Qinghai was explored from time and space perspectives,based on the shoreline information which was extracted manually with moderate-high spatial resolution remote sensing imagery.The results showed that,as a whole the Lake Qinghai's area decreased from 1974 to 2004 and then increased till 2016.In 2004 the area was smallest,4223.73 km²,smaller by 253.80 km² than that in 1974.From 1974 to 1987 the water surface shrank sharply.While the variation range was relatively modest with mean value of 6.85 km² during the period from 2000 to 2009.During the last 7 years,the water surface increased by 128.27 km².In 2012,there was a sharp expansion with 65.12 km² larger than pre-vious year;moreover the annual variation reached maximum,59.18 km².The shoreline of Sand island,which lies in the east coast,varied significantly during the past few decades.From 1974 to 2004 the maximum back distance from the coastline was 4.59 km,and the value of annual variation was 0.39 km in 2012.The increase of precipitation in Lake Qinghai region,and the enlarging inflow runoff,which benefited directly from local ecological environment control measures implemented by government,are two im-portant reasons to make the lake expanding in the last two decades.

Abstract:The paleogeography characteristics and water environment of Buha Estuary in Lake Qinghai are similar with those in Or-dos Basin and Sichuan Basin in the Late Triassic.The study on the types of organic matter and its abundance in the surface sedi-ment from Buha Estuary is significant to comparative sedimentology.The sediments were collected from river,prodelta,lakeshore,shallow lake and semi-deep lake in Buha Estuary region and were analyzed in aspects of whole-rock composition analysis,total or-ganic carbon (TOC) and examination of the kerogen.The results demonstrate that Ⅱ₂ kerogen is the major organic matter type in sediments and only a few Ⅱ₁ kerogen exist.TOC content in the sediments is no more than 4.29%,and the samples collected from semi-deep lake generally have high TOC content while the quality of organic matter is better than that of the other places.The clay minerals content in sediments,organic matter productivity and water depth are the major factors that affect the TOC content in the sediments of Buha Estuary.The semi-deep lake is a sedimentary environment which was the most favorable hydrocarbon source place because of its high productivity and good condition for organic matter.At the same time,according to the good correlation be-tween the water depth and TOC contents in sediments gathering from prodelta,shallow lake and semi-deep lake,the formula using the TOC contents has been established for reconstructing water depth.

Abstract:Phycocyanin and chlorophyll-a are characterizations of cyanobacterial biomass.These two pigments are detected in situ with fluorescence spectrum method or fluorescence intensity.However,due to the fluorescence interference between phycocyanin and chlorophyll-a,the accuracy of in-situ detection of cyanobacteria is relatively low,which limited the application of this method.In this study,we developed a novel method of fluorescence analysis based on a two-order matrix model and a multivariate calibra-tion linear model for the correlation between the fluorescence intensity and pigment concentration,which was verified by experi-ment.The established method decoupled the two mixed pigments as well as quantitatively analyzed the wavelength selection of exci-tation and emission and largely eliminated the fluorescence interference between phycocyanin and chlorophyll-a,and therefore,sig-nificantly improved the accuracy of in-situ detection of cyanobacteria.More importantly,our study can provide theoretical basis for the cyanobacteria detection sensor in how to select wavelengths.

Abstract:A very abundant desmids biota was found in Zhalong National Nature Reserve in 2011-2012,including 90 taxa in total.Among them,a Pleurotaenium species is proposed as new to science,Pleurotaenium parvulum Li,Fan&Wei.The new species is characterized of small cells and a long cylinder without processes,a truncated apex,five small nodules on cross section,cell wall smooth or with puncta,semicells with two axial longitudinal ridge-shaped chromatoplasts,and each with two pyrenoids.Differences between the species and allied taxa are discussed.