Abstract:At present, there are about 3000 lakes with more than 1 km² area in China. Most of them belong to Case II waters with alarge volume of shallow waters. Using theories and experiences of ocean water color remote sensing for reference, lake waterquality/color remote sensing has a prominent improvement. However, there still exist many problems mainly as follows: (a) there isnot a special sensor for lake water quality or color remote sensing up to now;(b) though many scholars have developed many waterquality parameter retrieval models, including semi-empirical models and semi-analytical models, there still exists a large gap frompractical applications;(c) lake bottom is one of the important influence sources to interfere lake water quality or color remote sensing;(d) it is very difficult for lake water quality or color remote sensing to develop an applied and operational atmosphere correctionalgorithm, which will have an important barrier on the practical application of lake water quality parameters retrieval.

Abstract:It is significant that remote sensing methods is used for monitoring cyanobacteria bloom in Lake Taihu, since it breaks outfrequently each year. Based on spectral characters of cyanobacteria bloom, different algorithm including single band, bandsubtraction and band ratio, were used for bloom mapping, with different instruments such as the MODIS/Terra, CBERS-2 CCD, ETMand IRS-P6. They noted that all these sensors were able to detect cyanobacteria bloom, while the algorithm of band ratio betweeninfrared and red band has a stable correlation with blooms, and it can be developed into a universal pattern. Except that, spatialcyanobacteria bloom concentrations were separated into five classes based on digital number values (DNs) in ETM and IRS-P6 Band4. This study showed that satellite observations was effectively applied to cyanobacteria bloom monitoring and early-warning forLake Taihu.

Abstract:Inversion of phytoplankton chlorophyll-a concentration of inland water body is hotspot and difficulty problem inwater quality remote sensing. This paper provides a method to resolve this problem. Basing on the characteristic spectralanalysis of chlorophyll-a, suspended matter, chromatic dissolved inorganic matter and pure water molecule in inland waterbody, the three-band model was spectrally tuned in accord with optical properties of Lake Taihu to optimize spectral bandscombination for accurate chlorophyll-a concentration estimation. The remarkable linear relationship was established betweenanalytically measured chlorophyll-a concentration and the three-band model. Depended on the favorable theory basis of themodel developed, this method achieved good result with high determination coefficient 0.8358 and low root-mean-squareerror (3.816 mg/m³), which was proved to be an useful tool to retrieval chlorophyll-a concentration in very turbid, hyper-eutrophicinland waters.

Abstract:MODIS, a good remote sensing image data source, is suitable to monitor cyanobacteria bloom for its free and high timeresolution, however, MODIS sensor receives distorting signals, due to the interaction between solar radiation and atmosphere, andatmospheric correction is necessary to acquire true surface reflectance and improve the accuracy of monitoring cyanobacteria bloom.In this paper, the basic theory of FLAASH atmosphere correction model attached in ENVI software, which derives from theMODTRAN 4 radiative transfer code, was introduced and explained. Then the FLAASH code was used to process MODIS data, andthe NDVI after atmospheric correction was compared with that before correction. Results indicated that atmosphere's influences werereduced and useful information was enhanced. In the end, the ratio between Band2 and Band1 which was obtained by FLAASHatmospheric correction, was used to extract the cyanobacteria bloom information with the threshold.

Abstract:This study investigates and analyses the possibility of cyanobacteria bloom detection as a case study in the Gulf of Finlandand southern Finish lakes. The results show that MODIS data are difficult to be used in cyanobacteria bloom early warning. The mainreason is that MODIS data are more suitable for CASE I waters as there are five bands in the spectral region of 400-550nm. However,for CASE II waters (estuary, coastal, and lakes), the maxima of reflectance spectra are shifting towards longer wavelengths withincreasing turbidity or increasing amount of CDOM. This suggests that the reflectance maximum in coastal waters often occurs in thespectral range of 550-670nm where MODIS data do not have any spectral bands. In contrast, MERIS data have three bands of 560,620, and 665nm at the spectral region of 550-670nm. The two bands at 620nm and 665nm are potentially important bands ofdetecting cyanobacteria bloom of the coastal waters (and/or lakes). The reason is that there are the phycocyanin absorption near630nm and a reflectance peak near 650nm. In fact, MODIS and MERIS data are unlikely applicable to warn potentially cyanobacteriabloom in its early stages, but able to monitor the already formed blooms. This methodology of satellite-based observations can beapplied to detection and monitoring of cyanobacteria bloom in Lake Taihu and coastal regions of China.

Abstract:Blue algal bloom in Lake Taihu was dynamically monitored using MODIS of hyper-spectral remotely sensed data, andcombined with water temperature, environmental condition of algal blooming was also discussed. Firstly, blue algal biomass wasestimated using simple ratio vegetation index, and progress of blue algal bloom was dynamically monitored using six sets of MODISdata. Then synchronous water temperature was retrieved from MODIS infrared bands 31 and 32 using window split model. The mainenvironmental factor of blue algal bloom- water temperature was analyzed, as well as the relationship between blue algal growing andwater temperature. The results showed that water temperature was an important environmental factor of blue algal growing;andappropriate water temperature (ranged from 24℃ to 30℃) was necessary condition of blue algal bloom;and high temperature (> 30℃)significantly inhibited the growth of blue algae.

Abstract:This year blue algae blooms occurred largely in Lake Taihu, which caused people pay close attention to environment ofLake Taihu once again. It is very important to extract the information of cyanobacteria bloom-forming to analyze the distribution ofcyanobacteria bloom and remote sensing is one of measures of monitoring and protecting water quality. In this paper, it takes theCBERS-02 CCD data as a main data source. The information of cyanobacteria bloom was extracted by the method of buildingdecision tree, and with NDVI as the test variable, threshold value was determined based on CART. It obtains better effects accordingto analyzing the extraction result. The information of cyanobacteria bloom is also extracted from MODIS image of May 17th, 2007.The present study provides technical reference for long-term monitoring cyanobacteria bloom-forming in Lake Taihu.

Abstract:There exists a phenomenon of different objects with a similar spectrum in the multispectral satellite images in Taihu Lake,which is caused by an influence of suspended matter and algae. So, it is easy to classify the water into submerged vegetations area bymistake. In this report, we firstly retrieved water transparency from Landsat TM image acquired on 15 July 2002. And then, thefollowing two types of decision trees were developed on the basis of the two vegetation index of RVI and NDVI: (a) atransparency-assisted decision tree, (b) a non-transparency-assisted decision tree. Finally, the lake was divided into the followingthree types: (a) the water area, (b) the submerged vegetation-dominated hydrophytes area, (c) the floating vegetation-dominatedhydrophytes area. The classification approach with transparency-assisted decision tree is a good choice to have a classification ofhydrophytes in Taihu Lake. We applied this approach into the Landsat TM image acquired on 15 July 2002. The classification resultsshowed that the submerged vegetation-dominated hydrophytes and the floating vegetation-dominated hydrophytes covered an area ofabout 407.6 km² and 82.2 km², respectively.

Abstract:Detection of cyanbacteria blooms in Taihu using vegetation index data from MODIS was carried out since cyanbacteriablooms broke out in May 2007. The results showed that MODIS was able to detect cyanobacteria bloom effectively. Algorithm ofband ratio between infrared and red band and values of NDVI or EVI can be used to analyze the distribution of algae. However, theformer two were difficult to distinguish high-turbid water from algae or identify areas with low density of cyanbacteria, whichresulted in the magnified or reduced areas of algae, while the latter one could constrain background noise properly mainly from waterand suspended matter. Therefore, based on the digital number values (DNs) of EVI band, an approximately actual distribution ofalgae was induced. The study showed that satellite observations could be effectively applied to cyanobacteria bloom real-timemonitoring system for Lake Taihu.

Abstract:In situ measurements of remote sensing reflectances (Rrs), backscattering coefficients(bb) as well as other relatedparameters had been acquired in 67 stations in Lake Taihu, in October, 2004. The total suspended matter (TSM) concentrations andabsorption coefficients(a) by ocean color elements had been derived from Laboratory analysis. Based on the analysis of in situ Rrsspectrum, several methods have been compared for TSM concentrations retrieval from Rrs. The results show that the methods bymeans of spectral ratios applied widely in ocean color remote sensing were basically applicable in TSM retrieval in Lake Taihu,whereas which all give a little high relative errors. Furthermore, the empirical coefficients for the algorithm only by use of 750nmband is also determined. The method by use of 812nm spectrum peak line height is provided in this article. The possible reasons thatthe methods by use of spectral ratios have higher relative errors in Lake Taihu have been explained in detail, as well as the reasonsthat the method using near infrared band information would be more accurate. At the same time, the advantages and disadvantages ofabove methods in the applications of ocean color remote sensing have been pointed out, as well as the requirements in terms ofsensors and retrieval methods in current applications..

Abstract:This paper discusses the method and mechanism of identifying and monitoring the cyanobacteria bloom based on MODISdata in Lake Taihu. Through the comparison of spectral reflectance value of different cyanobacteria concentration, it can be foundthat several wave bands are sensitive to cyanobacteria. Making use of the color composition, we can get the macroscopic distributioninformation of the cyanobacteria bloom. Furthermore, using the ratio index model, we can further confine the relative content of thecyanobacteria bloom. Finally through overlaying analysis of the cyanobacteria concentration distribution from multi-temporalMODIS data, dynamic changing information of cyanobacteria bloom can be obtained.

Abstract:The internal transcribed spacer 1 (ITS-1) was amplified from Hyriopsis cumingii in the five large lakes of China: LakePoyang, Lake Dongting, Lake Taihu, Lake Chaohu and Lake Hongze, and 430bp lengths of homological fragments of the ITS-1 wassequenced from 78 individuals of ten stocks. The homological fragment analysis showed that the average contents of G+C wereobviously higher than that of A+T. The nucleotide diversity of ITS of Lake Poyang was the highest, while that of Lake Chaohu wasthe lowest. The genetic distances among the six stocks from Lake Poyang were very near, which was from 0.0071 to 0.0092. Thegenetic distance among the five stocks from five large lakes were relatively far, which was from 0.0752 to 0.1381. The phylogenetictree of ITS-1 built with MEGA 3.1 showed that the six stocks from Lake Poyang clustered together independently, and had a relativecloser relationship with Lake Chaohu. The phylogenetic relationship between Lake Dongting and Lake Hongze was relatively closeand clustered independently. The stocks of Lake Taihu was an independent one, which diverged from those of Lake Pongyang andChaohu.

Abstract:The vast propagation of Hydrilla verticillata was studied based on the tissue culture technique. After aseptic system wasestablished, half and full strength of Murashige and Skoog-based liquid media(MS), in addition with 0.5-2 mg/L 6-Benzylaminopurine(BA) and 0.1-0.2 mg/L indoleacetic acid (IAA), were used for shoot induction. Meanwhile, quarter, half and full strength of MS plus0.1-0.2 mg/L IAA were useded for root induction. The results showed that the combination of full strength of MS plus 1 mg/L BAand 0.1 mg/L IAA was the best medium for shoot induction because the plants on such combined condition had more shoot numberand shoot biomass than those in the other mixtures. Half strength of MS plus 0.1 mg/L IAA or full strength MS plus 0.2 mg/L IAAwas the most proper media for root induction, and they can greatly promote the development of roots. The propagation was greatlyenhanced with the shoot induction in the optimal environment, amounting to 1800 times per quarter. The root induction made theseshoots grow into whole plants quickly, which enhanced the colonization ability of propagules at new habitat. In the outdoorexperiment, all plants survived at two densities (100 plants/m², 320 plants/m²) on three sediment types (sand, clay, sand+ clay1. 1V/V)). After 21 days, the population coverage was more than 70%. The experiments demonstrated that tissue culture was an effectivemethod of propagation of tool species to get the vast number of seedlings, and ensures the quality of the plants, and finally establishesa key basis for restoration engineering of submerged vegetation.

Abstract:In order to understand the effects of water and sediment on the growth of submersed macrophyte during eutrophication ofwaterbody, an experiment was carried out to study the effects of water and sediment from mesotrophic and eutrophic area of LakeDonghu on the growth of Vallisneria natans. Four treatments were designed, including eutrophic and mesotrophic culture conditions,and mesotrophic condition with inorganic nitrogen and phosphorus addition respectively. Indices of the growth experiments includedbiomass, both the number and length of leaves, number of sprout, were measured. Biochemistry indices including solublecarbohydrate content and free amino acid content were measured. The results showed that biomass, number of leaves and stolen of V.natans were the highest growing in mesotrophic condition, phosphorus addition was the second, and nitrogen addition was the third.The plant in eutrophic condition showed the lowest growth. The results indicted that high trophic condition inhibit the growth of V.natans significantly. Increase of inorganic nitrogen in mesotrophic water inhibited the plant more than did the increase of thephosphorus, suggesting that nitrogen enrichment during eutrophication may be more important than phosphorus for the decline ofmacrophytes. Soluble carbohydrate and free amino acid contents of V. natans in eutrophic condition were significantly higher thanthose in mesotrophic conditions, indicating that carbon and nitrogen metabolism of the plant were affected. This might be attributedto excessive accumulation of N in eutrophic waters of submersed macrophyte.

Abstract:Microcosm experiments were conducted to study the impacts of intensive cultivation of Anodonta woodiana on nutrientconcentration (different forms of phosphorus and nitrogen) and phytoplankton community structure. The results showed that thebivalve increased the concentration of total soluble phosphorus, total soluble nitrogen, and water transparency, but had decreased theconcentration of particle nitrogen. There were, however, no significant influences on the total phosphorus, total nitrogen, andortho-phosphorus. The intense filter feeding of Anodonta woodiana strongly restrained the growth of phytoplankton. Apparentchanges of phytoplankton community structure were observed. The percentage of Cyanobacteria sp. decreased greatly, while thepercentage of Chlorophyte sp. increased during the first 30 days' experiment. There was a slight increase of Bacillariophyte sp.percentage, but no change of Cryptophyte sp. The bottom-up effect of nutrient (i.e. phosphorus, nitrogen) on phytoplankton, whichwas significant in the control (no feeding), had been shifted to the strong top-down effects based on the Spearman correlation analysisbetween nutrient concentration and biomass of phytoplankton. With the decreasing of phytoplankton abundance, a sort of filamentousalga, Ulothrix sp., and some attached algae had gradually inhabited in the microcosm system. This study suggested that the use ofintensive bivalve for bio-manipulation may not be a good method to changenge the eutrophication status significantly, although itssuppression of phytoplankton and improving of water transparency were observed in the microcosms.

Abstract:Plankton are considered good indicators of water quality because they are highly sensitive to the environmental variation intheir short life spans. However, traditional studies on plankton community constructure have depended on taxonomic identificationwhich has historically been a difficult task. Recently, different fingerprinting techniques have been developed and appliedsuccessfully to analyze the community structure of bacterial and picoplankton. However, little is known to the whole planktoncommunity. In this study, we analyze DNA polymorphism of plankton communities in five different sampling stations of LakeNiushan by RAPD and PCR-DGGE and explore the relationship between DNA fingerprinting structure of plankton communities andenvironmental physico-chemical factors. The results were: (i) 9 of 40 screened random primers used in the study amplified a total of93 observable bands, 58 of which were polymorphic;the mean number of amplified bands at different sampling stations was 67, andstation Ⅴ had the maximum number (74) and station had Ⅰ the minimum number (61);(ii) a total of 102 bands (56 of 16S rDNAbands and 46 of 18S rDNA bands) were detected by PCR-DGGE, station,, and Ⅲ Ⅳ had more bands, Ⅴ station and Ⅰ had few Ⅱband;(iii) total phosphorus (TP), chlorophyll-a, chemical oxygen demanded (COD), hardness, and conductance rate at station wer Ⅱ ethe highest;dissolved oxygen (DO) and pH value were not obviously different among five stations. Based on physico-chemical factors,stationⅠ,, Ⅲ Ⅳ, and Ⅴ were grouped into a cluster, station Ⅱ grouped into a single cluster. Based on RAPD markers andPCR-DGGE markers, five sampling stations can be grouped into two clusters: stationⅠ and Ⅱ were grouped into a cluster, and station Ⅲ Ⅳ and Ⅴ were grouped into the other cluster. In conclusion, the DNA fingerprinting structure of plankton community wasclosely related to total phosphorus (TP). DNA based community level analysis is a fast, easy, accurate method to reflect the waterquality, and such data accumulation will play an important role in constructing one easy and sensitive molecular system for waterquality assessment.

Abstract:The Chinese paddlefish(Psephurus gladius(Martens))named as “the live fossil in the Yangtze River” is the indigenous species inChina, which is the biggest freshwater fish in the world. At present, the Chinese paddlefish has been in imminent danger, so it isextremely difficult to gain its fresh specimens. This research got the formalin-fixed tissues of Chinese paddlefish (11 individuals) asexperimental materials from the Institute of hydrobiology, Chinese Academy of Science. We have extracted the genomic DNA fromthe tissues of muscle, heart, fin and liver by optimizing a series of contrastive experiments, and consummated some researches onmolecular ecology by microsatellite molecular markers to realize its genetic characteristics.

Abstract:Effects of bicarbonate (HCO₃^-) alkalinity on the photosynthetic performance of Chlorella pyrenoidosa was investigated inpresent study. Photosynthetic activity, pigments, MDA and ultrastructure of Chlorella pyrenoidosa were measured for when they werecultured at two different alkalinities including 2.3mmol/L (ALK2.3) and 12.4mmol/L (ALK12.4), respectivily. At ALK2.3,photosynthetic activity was stimulated at the prophase of culture and then inhibited at the anaphase. At ALK12.4, it represented thesame phenomenon, but inhibition effects were weaker than those at ALK2.3. Ratios of Chl.b/Chl.a was increased, but Caro/T Chlratios was decreased at elevated alkalinities. The contents of MDA increased at ALK2.3 and decreased at ALK12.4. In addition,secretion of glycocalix-like layer was remarkably stimulated at elevated alkalinities. These results showed that elevated alkalinitiespromoted algae carbon assimilation and stimulated secretion of glycocalix-like layer. Carbohydrate could alleviate stresses at elevatedalkalinities. Secretion of glycocalix-like layer could decrease the synthesis of excess products of photosynthesis and relieve feedbackinhibition, which will increase the stress tolerance of C. pyenoidosa at elevated alkalinities.

Abstract:A concept Aerated Vertical-Flow Wetland is introduced in the text, experimental researches through a pillared unit werecarried out on the performances of treating domestic wastewater in the rural area of Lake Dianchi valley, Yunnan province. Theoxygen transfer efficiency of the experiment device reached 14.04%. And the experiment data showed that, with hydraulic loading as15.29 m³/(m²·d) and airflow-waterflow ratio 1:2, average BOD5 and NH4-N removal respectively reaches 74.4% and 63.5%. The BOD5 and NH₄-N values within outflow get to 4.96mg/L and 2.72mg/L. It resulted that, the Aerated Vertical-Flow Wetland Technicswas effective and economical for suburb domestic wastewater treatment with high hydraulic loading.