Abstract:The present paper introduces the recent progresses on the production mechanisms and environmental fates of microcystins—the most common toxins produced in bloom-forming cyanobacteria, in particular, Microcystis. The review contains three parts:(1)biological origin, structure and properties of microcystins; (2)synthesis, cellular distribution, production and possible function of the toxins; and (3)environmental fates of the toxins. Recent progresses, problems and perspectives in the study of environmental fatesof toxins are viewed and discussed.

Abstract:Phenotypic plasticity is an ability that an organism activates different phenotypes to its environment. It is an importantsurvival strategy when organisms live in an unstable environment. In aquatic ecosystems, numerous studies prove that planktonicorganisms are able to detect the presence of potential predators through predator-released kairomones, and then evoke someanti-predator responses. Daphnia is a good model of the organism that can be studied for the phenotypic plasticity of zooplanktoninduced by predator-released kairomones. This paper provided an overview of anti-predator phenotypic plasticity of Daphnia inhistorical life traits, morphological characters, behaviors and physiological parameters, and provided the mechanism explanationand ecological significance. These plastic anti-predator changes are shaped by differences in historical exposure to the inducingpredator. Daphnia can inherit these abilities from their parent. Daphnia originated the no-predator ecosystems does not have theability of anti-predator phenotypic plasticity. In general, phenotypic plastic responses of Daphnia induced by predator kairomonescan decrease the efficiency of predation of predators and allow Daphnia a greater chance of survival when facing predators.

Abstract:Distribution of soluble reactive phosphate (SRP) in pore waters is a sensitive indicator showing geochemical properties ofphosphorus in sediments. Concentration of SRP in synthetic solutions was obtained based on the principle of diffusive equilibration inthin films (DET). Analytical procedure generally includes equilibration of the gels in solutions or pore waters, section of the gels afterretrieval, back elution of phosphorus in the gels, and analysis of SRP in the eluents. Equilibrium and extraction times weredetermined at 24h and 16h, respectively, with 0.25mol/L HNO₃ used as an extractant. Concentrations of SRP in pore waters ofdifferent sediments measured by using the established DET technique agree well with its actual values, and the variations aregenerally within ±5%. Analytical results for sediment profiles with this technique, which has a vertical resolution at about 3mm, alsoshow comparison with those using sampling techniques of Rhizon and Mini-Peeper. The established DET technique was used tomeasure SRP profiles in sediments of macrophyte- and algal-dominated regions in Lake Taihu. Peak-shape distribution and horizontalheterogeneity of SRP were observed in macrophyte-dominated region, while an upward and increasing movement of SRP wasobserved in algal-dominated region with an increase in water temperature.

Abstract:Undisturbed sediment cores from four sites in Meiliang Bay were collected from north to south of Lake Taihu, thenincubated by flow-through technique in the laboratory. The denitrification and anaerobic ammonium oxidation (anammox) rates weremeasured by stable isotope tracing technique, isotope nitrogen product measurement and isotope pairing technique. The resultsshowed that denitrification and anammox rate were from 46.36±13.26 to 16.34±22.74μmol/(m²·h) in the Meiliang Bay and from7.50±2.21 to 2.05±2.90μmol/(m²·h) on the open lake areas out of the bay, respectively. Denitrification rates were significantly higherin the north of the Meiliang Bay than in the south and open lake areas. The dominated nitrogen removal process was uncouplednitrification-denitrification(Dw) which utilizing nitrate in overlying water as substrate in north Meiliang Bay, and coupleddenitrification(Dn ) was dominate process in the open lake area. The concentration of NO₃^-and O₂penetration depths were mainfactors affecting the distribution of Dn and Dw . The anammox proportion of the total nitrogen removal ratio was 12%-14% in theMeiliang Bay, and 11% out of the bay, which was correlated with the denitification rate and influenced by the intermediate product(nitrite) of denitrification.

Abstract:Aiming at the problem of black-odor, oxygen deficiency and ammonia-nitrogen pollution of polluted rivers, a new type ofecological floating bed—micro-aerated ecological floating bed was developed, which combined biofilm packing, floating aquaticmacrophyte and auxiliary aeration device. The purification efficiency of the polluted river water was studied by the model experimentin the outlet of Daqing River. The results showed when the hydraulic loading was 1500mm/d, the mean removal efficiencies of totalnitrogen, ammonia nitrogen, total phosphorus and phosphate were 81.1%, 91.3%, 72.7% and 92.5%, respectively. Additionally, thefloating bed showed better removal effect on organic matters. The cost of micro-aerated system to treat 1m³ of polluted river waterwas only 0.007 Yuan. The micro-aerated ecological floating bed ran steadily, had a high efficiency of pollutants removal and lowenergy consumption. It was suitable for the environment of flowing water, which could be used in polluted river and estuary.

Abstract:The process of water purification was studied using immobilized nitrogen cycling bacteria, including ammonibacteria,nitrosobacteria, nitrifying bacteria and denitrifying bacteria, which applied and screened for natural water of Lake Jinshan. The resultshowed that the water quality was improved obviously after running a period of time. Concentrations of NH₄⁺ -N, NO₂^--N, NO₃^- -Nand TN declined. NH₄⁺-N concentration had reached national Ⅰ class of water quality index. TN concentration had reached Ⅱclass.The N₂O flux of Lake Jinshan increased during three months from April to June, which were 23.51μg/(m²·h), 29.52μg/(m²·h) and59.10μg/(m ²·h) respectively. The experiment has proved that the techniques of immobilized nitrogen cycling bacteria could purify theurban lakes significantly.

Abstract:Studies on community structures of phytoplankon, including genus richness, density and biodiversities, and regressionanalysis between community index of phytoplankon and water quality parameters were carried out from Jan. to Dec. of 2007 in XixiWetland of the first project-circled aera, Hangzhou. 56 genus of algae were found, of which 73.21% were Chlorophyta andBacillariophyta. The annual mean density of algae from Ⅰ station to Ⅳ station were 2.88×10⁸, 0.37×10⁸, 0.47×10⁸and 0.71×10⁸cells/Lrespectively, of which 93.76% were Chlorophyta and Cryptophyta, and the Chlorella, Cryptomonas and Chamydomonas weredominated in the algae community. The algae diversity indexes of Genus Marglef from Ⅰ station to Ⅳ station were 1.17, 1.10, 1.08and 1.06 respectively. According to values of algae comprehensive index, Xixi Wetland has suffered serious pollution and can beregarded as eutrophication status. Logarithm density of algae was positively correlated with COD Mn value in station Ⅰ and station Ⅲ(P<0.01), and positively correlated with water conductivity value from Ⅰ station to Ⅳ station(P<0.01).

Abstract:Dynamics of composition of different Microcystis spp. genotypes from June to November, 2008 in Meiliang Bay of LakeTaihu in China were investigated based on denaturing gradient gel electrophoresis analysis of PCR-amplified ITS (internaltranscribed spacer sequence) fragments. Simultaneously, we investigated the relative abundance of microcystin-producingMicrocystis spp. (the ratio of the toxic Microcystis to total Microcystis) based on microcystin synthetase gene (mcyA) and partialMicrocystis-specific 16S rDNA sequence using real-time PCR. The results of this study indicated that there were shifts ofcomposition of different Microcystis genotypes during algae bloom in Lake Taihu. The most abundant genotypes were found in thelate of August, September and October. Genotypes M5 and M10 were found every month. A total of twelve main genotypes werefound, and the relative abundance of each genotype changed during the development of algae bloom. Quantitative real-time PCR(qRT-PCR) revealed that the abundance of toxic Microcystis increased from 0.75% to 32.16% from June to October and decreasedsignificantly in November.

Abstract:Fubao Bay is located in the north of Lake Dianchi, which is one of the most seriously polluted bays in the lake. Two mainrivers, Haihe River and Daqinghe River flow into Fubao Bay from the north. Four sampling sites were settled in this bay, and thesediment samples were collected by using Petersen grab. For the first time, the study of recruitment ability of Microcystis in differentsediment environments was carried out in simulation devices. The results in the present study showed that the recruitment ability ofMicrocystis was quite different depended on its habitat environments. The Microcystis recovery was inhibited in lacustrine sedimentsnear estuary, and the maximum biomass (calculated as chlorophyll-a) was pretty lower than other sampling sites. Compared amongEast Coast Area, West Coast Area and Hydraulic Mud Fill Area, the Microcystis biomass were only 4.7%, 6.6% and 11.9%,respectively. And Microcystis biomass (calculated as Microcystis cell numbers) were about 5.2%, 10.3% and 19.4%, corresponding.All the results indicated that sediments in estuary of Fubao Bay were not appropriate for Microcystis recruitment. The contribution of“seeds bank” recruiting to form HABs in this bay could be much less than the wind-induced external loading. All these results couldbe helpful in Microcystis blooms forecasting, preventing and controlling in the future.

Abstract:Excess²¹⁰Pb dating is not only an important method for sediment dating, but also a major environmental tracer. In aridregions, excess²¹⁰Pb deposited in lake sediment mainly depends on wind erosion recycle besides the atmospheric precipitation fluxbackground. Therefore, the higher excess²¹⁰Pb is a potential for identifying the aeolian activities. This paper makes a systematicalanalysis on the data published in recent years, and calculates the multi-year average excess²¹⁰Pb flux in different lakes. Thus, the areasin which multi-year average excess²¹⁰Pb flux that exceeded atmosphere flux background could be recognized preliminarily as regionalaeolian deposits. And then, we use the excess²¹⁰Pb model (PF-CRS) to calculate the lake sedimentation rates in some typical aeolianregions. At last, we compare the results with the dust records correspondingly so as to estimate the reliability of this method.

Abstract:Four sediment cores were collected at three sites from Pumoyum Co, Southern Tibet. Sedimentation age was constructedby using ²¹⁰ Pb and¹³⁷Cs measurements from one short core. Environmental proxies such as total organic carbon, inorganic carbon,grain size and element concentrations were analyzed for upper parts of other three cores. The proxies from different cores werecompared and then environmental changes during the last ca. 200 years were discussed. Although proxies changing trends of differentcores are similar, obvious differences appear in both detailed variations and proxies values, probably resulting from different waterdepth, underwater landform conditions and distances to rivers among the sites. Environment condition in this area was stable before1900AD, but it fluctuated during 1900-1940AD with enhancement of surface erosion and increased sedimentation rate. Remarkablechanges took place at about 1940AD, showing that the temperature increased greatly, grain size of sediments became coarser and thelake was in the state of shrinkage, indicating environment in this area changed to a warm/dry state.

Abstract:This paper was an attempt to use the ¹³⁷Cs mass balance model for assessment of recent deposition rates in Lake Qinghai.¹³⁷Cs concentration peak at the depth of a few centimeters in the deposit profiles of Lake Qinghai and other lakes with lowerdeposition rates may be caused by the nuclide downward diffusion and migration progresses after the ¹³⁷Cs deposited on the surfaceof lake bottom mud. Therefore, the interpretation of the sediment layer at the ¹³⁷Cs peak depth depositing in 1963 and the calculationmethod of sediment deposition rates under that assumption may not be reasonable. Local¹³⁷Cs reference inventory was117.7mBq/cm² in 2005 obtained from grass land of the flat lakeside. ¹³⁷Cs inventories of the six lake sediment cores collected fromthe Island Hill of the center of Lake Qinghai to the Fish Port in the south-eastern lake ranged from 92.9mBq/cm² to 325.0mBq/cm². Itwas clear that sediment deposition apparently occurred in the south-western part of the lake, particularly, the deposition is quite fastat the QHH02 Core position, which is located in the front of the underwater alluvial fan. However, sediment deposition was very slowat the centre part of the lake. The average ¹³⁷Cs concentration of the deposited sediments in Lake Qinghai since 1963 was estimated tobe 30mBq/g by analyses of the ¹³⁷Cs concentrations from the lake mud in surface layers, the sediment discharged from inlet rivers,and the soil in surface layers on the grass land in the catchment. The average deposition rate in the centre of the lake was 0.020cm/acalculated by the ¹³⁷Cs mass balance model, which agreed to 0.018cm/a of the specific sediment yield of the Buha River, but muchlower than the reported deposition rates estimated by conventional dating techniques. The deposition rate of the QHH02 Core was0.229cm/a, suggesting that the deposition rates in the south-western part of the lake were much higher than the rates in the centre partof the lake and which was twice of the reported deposition rate of Lake Qinghai.

Abstract:The organic carbon production of phytoplankton near the Trestle monthly and at four stations quarterly in Lake Taihu fromJanuary 2007 to December 2007 was investigated, and its influence factors were analyzed. The results showed that there wereobvious temporal and spatial differences in the production of organic carbon in Lake Taihu. The high values of organic carbonproduction were recorded in spring and summer. The production of organic carbon was higher in the area where the phytoplanktonwas dominated by Cyanophyta and lower in the aquatic areas.

Abstract:The algal community was studied in Heihe channel in Heilongjiang River during May to October of 2006-2007, accordingto the taxon and relations between algal assemblage structures and environmental variables based on data from six monitor stations,and was analyzed by use of Canonical correspondence analysis. It revealed that biology oxygen demand, total phosphorus, watertemperature and chemical oxygen demand from 7 water environmental variables are significant fractions of the distribution andvariation of algal community. CCA result indicates that, the algal community and space distribution are correlated with environmentalvariables, the variety of the algal community may become a useful monitor for river environments.

Abstract:This paper was studied the eco-characteristics of phytoplankton in Lake Wuli, Lake Taihu in 2007. The results showed that 8classes including 123 species have been founded in Lake Wuli. Among them, dominated Chlorophyta has 57 species, accounting for46.3% of the total phytoplankton species, and Bacillariophyta has 23 species, taken the second place, accounting for 18.7% of the totalphytoplankton species. There were much more species in winter and spring than that in summer and autumn. The quantity and biomass ofphytoplankton in Lake Wuli in 2007 ranged from 386.2×10⁴to 5581.9×10⁴cells/L and 0.541 to 3.491mg/L, respectively. Dominated classboth in quantity and biomass was Chlorophyta, then was Cyanophyta, and the third was Cryptophyta. The quantity of phytoplankton inthe order from large to small was: Summer>Spring>Autumn>Winter. Seasonal succession of phytoplankton was consistent with rule ofPEG (Plankton Ecology Group) model except Chlorophyta. The analysis results of similarity showed that the eco-environment of LakeWuli in January was similar to that on March, April and May, and the eco-environment in June was similar to that in July, August,September and November. The analysis result of the predominance index showed that there were 14 predominant species includingChlorella vulgaris, Chl.amydomonas microsphaera, Chroomonas acuta, Microcystis aeruginisa in 2007 in Lake Wuli, and the numbers ofpredominant species were all more than two species in every month. Furthermore, the predominant indexes were not high, ranging from0.02 to 0.78. The analysis results of diversity and uniformity showed that the diversity index ranged from 1.5 to 2.7 and uniformity indexfrom 0.26 to 0.59, respectively, which meant that both diversity and uniformity of phytoplankton were good status in the lake. It could beconcluded that the phytoplankton community structure in Lake Wuli was complex in the ecosystem.

Abstract:The phytoplankton of Lake Ulungur was investigated seasonally from November, 2006 to July, 2007. A total of 164phytoplankton species (including a number of unconfirmed species) was detected, which belonged to 90 genera, 8 phylum. Amongthem, Anabaena bergii was a new record species of cyanophyta in Xinjiang Uygur Autonomous Region, and two species ofbacillariophyta, Chaetoceros sp. and Thalassionema sp., belonged to marine algal. In each season, the phytoplankton compositionwas dominated by Chlorophyta and Bacillariophyta, secondly dominated by Cyanophyta, Euglenophyta, Xanthophyta, Chrysophyta,Cryptophyta and Pyrrophyta. The number of phytoplankton species was the highest in autumn (141 species), followed by the summer(128 species) and spring (121 species), the lowest in winter (95 species). There was an obvious seasonal characteristiscs for thedominant species. Raphidiopsis sinensia, Teraëdron minimum, Selenastrum minutum, Chlorella vulgaris and Synedra acus were dominant species in the whole year, while Synedra ulnacould only be found in spring, summer and autumn. Kirchneriella contorta and Chlorellaellipsoidea dominated in summer, and Chlorococcum infusionum and Treubaria crassispina dominated in winter. The standing cropof phytoplankton peaked only in summer with a biomass of 6.77mg/L and the minimum biomass of 1.45mg/L occurred in winter.Compared with historical data, the phytoplankton composition had remarkable changes. The growth of green alga and diatom weremost notable, while the number of the phytoplankton increased many fold in the past 30 years.

Abstract:A SIMRAD EY60 echo-sounder with 200kHz split-beam transducer was used to survey the fish school in LakeQinghai on August 16-18, 2006. The transducer was tied on the side of the ship downward at one meter depth. The cruising speed is8-10km/h. Also, a GPS was connected with EY60 echo-sounder for obtaining the survey position data. The pulse duration was setat 64μs. At post-processing, the Sonar5-pro software (versions 5.9.6) was used to analyze the echo-sounder data. The results show that the Gymnocypris przewalskii is not uniform distribution in horizontal direction in Lake Qinghai, and appears the feature of smallaggregation. For different survey subarea, the density of fish is 0.168-12.8ind./1000m³, and the average is 1.16ind./1000m³where themaximum appeared near the Buha estuary. The biomass of catchable size is estimated at 6.5×10 ⁷ ind. near 15275 ton, at35.6×10⁷ -118.4×10⁷ind. with 95% confidence interval. Our results also indicated that the EY60 echo-sounder is suitably applicablein Lake Qinghai to estimate the fish productions effectively.

Abstract:Changes of the concentrations of COD Mn, BOD₅and NH₃-N from main sections of the middle and upper reaches of EastRiver were identified, by using the method of seasonal Kendall test for water quality data from Longchuan, Heyuan and Boluomonitoring stations during 2001-2007. The results suggest that: (1) the concentrations of BOD₅ increase significantly at all stations;(2) the concentrations of COD_Mnand NH₃-N do not display a significant trend at Longchuan control section, and the concentrationsof COD_Mn showed a decreasing trend and NH₅-N showed an increasing trend at both Heyuan and Boluo control sections; (3) changein the rate of water quality from the middle reaches is larger than that from the upper reaches; (4) the water quality change is mainlyinfluenced by the change of waste discharge.

Abstract:The spatial distribution, temporal changes of water transparency and relationship between transparency and turbidity,suspended substance, chlorophyll-a, radio of total nitrogen and total phosphate, pH were analyzed based on monthly (May-October)monitoring data in Lake Wuliangsuhai from 2006 to 2008. The results indicated that the water transparency in Lake Wuliangsuhai in2006 to 2008 ranged from 0.33m to 1.62m with a mean value of 0.93m, and the distribution trend of transparency took on increasingfrom the northeast to the southwest. The correlation analysis results showed that turbidity and the amount of suspended substancesare two significant factors that affected the transparency. Their regression functions can be represented as SD=1.489x ^-0.471 (R=0.83,N=100, P<0.0001) and S^1/4 =-3.948lnSD+12.055 (R=0.65, N=100, P<0.0001) respectively.

Abstract:The temporal and spatial variation characteristics of nitrogen forms are very important for environmental pollution controlof lake. Concentrations of different nitrogen forms were studied using the geostatistical analysis module of ArcGIS in LakeWuliangsuhai. The results indicate that average concentrations of total nitrogen were higher in summer and winter than autumn inseasonal time series, the average concentrations of ammonia nitrogen were lower in summer than autumn and winter, and the averageconcentration of nitrite nitrogen was higher than nitrate nitrogen in different seasons. In space, concentration distribution of differentforms ofnitrogen showed gradually decreasing from north to south. In a word, nitrogen pollution is very serious in LakeWuliangsuhai. The main pollutions were sourced from farm field drainage of the Hetao irrigated areas, industrial waste water anddomestic sewage close to main irrigation canal, which caused different forms of nitrogen contents decreases with the discharge of flowingwater. However, in the region of density reed and aquatic, the contents of nitrogen forms will change with increase or decrease.

Abstract:Based on the proportion of cross-section category, the Nemerow Comprehensive Pollution Index was calculated for thewater and sediment quality evaluation in Ebinur Lake Catchment during high-water period, 2008. The result showed that the mainindicators (TN, TP and NH₄ ⁺ -N) exceed the national standards, especially in Bortala river, i.e., TP exceeded 14.1 times and TN 10.1times. Furthermore, according to GB3838-2002, the monitored stations showed serious water deteriation with about 30% belowCetegory in Ⅴ Ebinur Lake Catchment. The result indicated that Lake Ebinur drainage area during high-water period pollutedmoderately.