Abstract:Chromophoric dissolved organic matter (CDOM) is the light absorption fraction of dissolved organic carbon (DOC) that absorbs light in both the ultraviolet and visible ranges. The spatial and temporal distribution of CDOM in aquatic ecosystems can have important effects on ecosystem productivity, negatively impacting primary productivity due to CDOM absorbs light at both ultraviolet and visible wavelengths while positively impacting secondary productivity by fueling of microbial respiration by photo-degraded CDOM. In water color remote sensing, overlaps of pigment absorption spectra with CDOM absorption at blue wavelength generally complicate the use of chlorophyll a retrieval algorithms that are based on remotely sensed ocean color and lead to overestimated chlorophyll a concentration. In addition, high concentrations of CDOM can also act as a photoprotectant against UV damage for aquatic organisms. However, the protection against UV radiation provided by dissolved humic material for aquatic biota may be diminished if photodegradation of CDOM by UV radiation and acidification increase the UV transparency in lakes. CDOM absorption measurements and their relationship with DOC, and fluorescence are presented in Meiliang Bay of Lake Taihu based on a field investigation and lab analysis to show the spatial distribution of CDOM. Absorption spectral of CDOM was measured from 240 to 800 nm. Concentrations of DOC ranged from 10.48 to 19.72 mg/L with an average of 13.20 ±2.78 mg/L. CDOM absorption coefficients at 280 nm and 355 nm were in the range 18. 73-31. 91 m^-1 ( average 23.19±4.36mm^-1) and 4. 63-7. 14 mm^-1 (average 5. 76±0. 90 mm^-1)，respectively. The values of the DOC-specific absorption coefficient at 355 nm ranged from 0. 34 to 0. 57 L/( mg · m). Fluorescence emission at 450 nm, excited at 355 nm, had a mean value of 1. 69 ±0. 77 nmm^-1. A significant lake zone difference is found in DOC concentration, CDOM absorption coefficient and fluorescence. This regional distribution pattern was in agreement with the location of sources of yellow substance ： highest concentrations close to river mouth under the influence of river inflow, lower values in outlet of Meiliang bay. CDOM fluorescence and absorption coefficient were significantly and positively correlated. The results show a good correlation between CDOM absorption and DOC coefficients during 280-500 nm short wavelength intervals. The coefficient of variation between CDOM absorption and DOC concentration decreased with the increase of wavelength from 280 to 500 nm. The linear regression equations between fluorescence, DOC concentration and absorption coefficients at 355 nm are: F_n ( 355 ) = 0.692( ±0. 135)a(355)-2.291 (±0.786)，a(355) =0.233(±0.061)DOC +2.690(±0.816)，respectively. The exponential slope coefficient ranged from 11.0 to 14.9 um^-1 with a mean value 13. 86 ± 0. 91um^-1， 15. 8-20. 7 um^-1 with a mean value 18. 54 ± 1. 11 um^-1 and 9.9-13. 9 um^-1 with a mean value 12. 93 ± 0. 92um^-1 over the 280-500 nm, 280-360 nm and 360-440 nm intervals. A significant negative linear correlation was found between spectral slope coefficient and DOC specific absorption coefficient, but a significant positive linear correlation for spectral slope coefficient and the ratio of a( 250)/a( 365 ). Larger specific absorption coefficient corresponds to smaller a (250)/a (365) and spectral slope coefficient, which shows higher ratio humic in CDOM.

Abstract:Processed and analyzed the hyperspectral data-Hyperion on August 19^th 2004, we estimated chloro-phyll-a concentration using ratio and differential coefficient method in Lake Taihu. But these two models ^, applicability confined in single area and single phase. In this paper we used mixing spectral analysis model for extracting chlorophyll-a concentration and mapping the distribution of chlorophyll-a concentration. The result shows that the new style of remote sensing data Hyperion can be used for monitoring chlorophyll-a concentration，and that mixing spectral analysis is an optimal method for estimating water chlorophyll-a concentration.

Abstract:Most lakes in eastern China are exploited in the form of enclosure culture. The high density enclosure culture area is easy to cause lake eutrophication and deteriorate the water quality. So the lake enclosure culture area is focused by people and is usually extracted by using the multi-temporal remote sensing data and the multi-spectral classification or the manual digitization means. The multi-spectral classification is easy to confuse enclosure culture area with the natural water area and the manual digitization demands much time. This paper suggests a new method using the image texture information to extract lake enclosure area. The result is more accurate and the method demands less expense. Lake Baima is the study area and the image of the area is multi-spectral data of China Brazil Earth Resources Satellite 02. First the water area A the man-made area and the bare soil which has the similar special characteristics with the water are extracted by using the normalized difference water index. Then the principal component analysis was used to compress the multi-spectral data of the study area and enhance the texture informa-tion of the image. The third step Grey Level Co-occurrence Matrix (GLCM) was used to analyze the image, select a proper threshold of mean value which quantifies the GLCM. Finally, the lake enclosure culture area was extracted by using the decision tree.

Abstract:Trophic state index is an important and synthetic standard for estimating the pollution status of water body. It requires large scale field sampling work and complicated indoor chemical analysis involving traditional analytical techniques, as well as complex calculations applying complicated formulas. In this study, through the analysis of the hyperspectral remote sensing data and the water body trophic state level, the remote sensing reflectance and trophic state index of the water body, Lake Taihu, are calculated, The result of correlative analysis, found the hyperspectral sensitive bands to be inverse to the water-body^, s trophic state index and sensitive bands and bands^, combination (ratio) in established models. The comparative baseline model selected is a power function model TSI_C =68. 76χ^0.5199, with an independent variable of R_717nm. The result, through precision analyses using the other 12 points, found the differences between practice and forecast along half one grading interval, therefore providing reliability and practicability. In conclusion, it is possible to monitor a water-body^,s trophic state index directly with hyperspectral remote sensing data and some evidence for the theoretical basis of investigating water quality in a large scope using hyperspectral remote sensing data is justified.

Abstract:The quantitative relationship between Spectral Reflectance (SR) characteristics of water and chlorophyll-a( Chi. a) concentration in Lake Taihu was analysed based on the in-situ data collected by ASD FieldSpec Hand-Held Spectroradiometer. The results reveal that the Chi. a concentration can be quantitative retrieved using SR at wavelength of 720 nm，or using the ratio of SR at wavelength of 806 nm and 507 nm. The model using SR at wavelength of 720 nm is an effective retrieval model whether Chi. a concentration > 10ug/L or Chi. a concentration < 10 ug/L, while the model using the ratio only retrieve Chi. a concentration effectively for Chi. a concentration < 10ug/L. It was found that there is high correlation between Chi. a and the first derivative at 690 nm, also high correlation between Chi. a and the second derivative at 702 nm through spectral derivative method，but the model retrieve accuracy using the first derivative or the second derivative is not significantly improved compared to the model directly using SR. But the retrieval accuracy using the second derivative is a little higher than the model using the first derivative. So it was concluded that the Chi. a Concentration in Lake Taihu can be retrieved using SR at wavelength 720.

Abstract:Based on the absorption coefficients at 16 sampling sites in Meiliang Bay on July 17 2004, the absorption coefficients of algal particles were discriminated from those of nonalgal particles by the method of spectral criteria, and compared with those by methanol-extractions. The results were as follows. Discriminated from absorption coefficient of nonalgal particles by methanol-extractions, the absorption coefficient of alga particles shows the absorption characters of nonalgal particles when the concentration of nonalgal particles is high. The absorption coefficients of algal particles are overestimated especially in short wave band. By the method of spectral criteria, the absorption coefficients of nonalgal and algal particulates can be successfully separated. Compared with the partition by methanol-extractions,the limear correlation coefficients between absorption coefficient of algal particles at 440 nm and 675 nm and the concentration of chlorophyll a significantly increase. The limear correlation coefficients increase to 0. 8901 and 0. 8401 from 0.66 and 0. 75 at 440 and 675 nm, respectively. As far as the method of methanol-extractions is concerned,the spectral shape of absorption coefficient of particles matter significantly affects the degree of over-estima-ting the absorption coefficient of algal particles. When the spectral shape of absorption coefficient of particles matter is much more similar to that of alga particles, the error is lower； on the contrary, the error is bigger.

Abstract:The metal contents in the sediments are influenced not only by human pollutants，but also by grain size and mineral composition of the sediments, which should be evaluated in the study of heavy metal. The metals contents and their correlations with grain size in sediments of core MS from Lake Taihu are studied in this paper in order to evaluate the grain size effects on metals contents. The metals in core MS can be classified into two categories according to their variation characteristics. Al, Fe，K etc belong to one category, the contents of which are high in the middle-lower section of the sediment core and low in the upper section; Na belongs to the other category, the variation of its content is opposite with the first category. According to the correlations of the metals and grain size, clay content was selected as the normalization component of metals. After normalized by the clay content, the metals contents take on consistent variation along the sediment core. The analysis results show that the metals contents in Core MS are influenced mainly by grain sizes composition and the normalization of metals content must be taken during the study of metals variation and pollution evaluation.

Abstract:Vegetational succession and climatic change since middle Pleistocene in Heqing Basin in Yunnan Province are discussed according to the sporopollen analysis for the top 155m length core and about 800 kaBP history from Heqing deep drilling core. This core is the first drilling core of Environmental Drilling Programme in Chinese continent. The results show that vegetation in the surrounding mountains in Heqing cathchment experienced many times changes among coniferous forest dominated by Pinus，montane coniferous and broadleaved mixed forest and cool temperate coniferous forest during the period about 800 kaBP to 6. 98 kaBP. From 6. 98 kaBP to today, vegetation has immensely changed, such as forest degraded quickly and vegetation dominated by herbs, when human activities have begun affecting vegetation. Human activities represent disafforestation and planting crops and so on. Climate corresponding to vegetation evolution may be divided into five stages and contains many times cool and warm, dry and humid gyrations since about 800 kaBP.

Abstract:Based on artificial rain experiments and field monitoring to sub-watersheds in different spatial scale (from 1 to 400 km² in area) in Taihu upper-river basin，The runoff mean concentration of non-point source nitrogen and phosphorus are assessed according to different spatial scale field monitoring. The discrepancy of watershed nutrient decay function，due to different soil infiltration and runoff routing process in different watershed spatial scale， is analyzed. The results proved that runoff mean concentration of nitrogen and phosphorus in different watershed scale is with more discrepancy. The runoff mean concentration of nitrogen and phosphorus based on overland flow monitoring is higher than that of watershed outlet monitoring, because the overland flow monitoring does not represent the soil infiltration and runoff routing processes relating to nutrient decay. The forest land of watershed, with strong soil infiltration and more natural stream systems，have more nutrient decay function than that of the farm land of watershed with weak soil infiltration and artificial canal systems. It is important factor of increasing non-point source nitrogen and phosphorus to alter watershed hydrological system and ecological system by modem farm activities. Restoration and remediation of natural ecological stream system is helpful to non-point source pollutant abatement of watersheds.

Abstract:Based on the low hill small red soil watershed in the Ecological Experiment Station of Red Soil of China Academy of Sciences, the variations of nutrient concentrations in the sediments(0-5 cm, 5-10 cm, 10-15 cm, 15-20 cm, 20-25 cm, 25-30 cm)of 4 ponds under the slopes of different land use patterns were investigated. The 4 ponds were B pond (locateal in the downside slope of Chinese chestnut land)，C pond (locateal in the vicinity of the village)，H pond (locateal in the downside slope of peanut land) and S pond (locateal in the downside slope of paddy field respectively. The results showed that： The nutrient concentrations in sediment of 4 ponds were differed obviously. The highest concentrations of TOC, TN, AN and TP in 0-15 cm sediment were appeared in C pond, and the lowest were in H pond. In 15-30 cm sediment, the highest concentrations of TOC and AN were found in B pond, while TN and TP were found in C pond. The concentrations of AP of the sediment in 4 ponds were trace except the 0-15 cm sediment in C pond with low level. This suggested that the land use patterns had significant effect on the nutrient concentrations in the sediments of the ponds. The nutrient concentrations of the sediments (0-30 cm) in 4 ponds all decreased from surface to bottom. The TN and AN with the maximal descent were found in C pond, and the TOC and TP were both in B pond. The most descents of nutrient concentrations in sediment in each pond appeared in superficial sediment layers. The accelerations of the nutrient accumulating in sediment indicated that the export of nutrient from each land use pattern had increased in recent years obviously, and one of the main causes of the nutrient enhancement in the sediment was the transform of the traditional agricultural cultivation fashions.

Abstract:The nitrogen surplus of the upstream agricultural land have a great impact on the eutrophication of the Lake Taihu. Based on the suburban agricultural data of the year 2002, the nitrogen surplus was calculated for the agricultural land of the upstream Taihu. The calculation results show that the agricultural land has a total surplus of 134. 8 x 10³ t/a, and the kilogram surplus per hectare agricultural land is 178. 9 kg per year. The east and west Tiaoxi catchments have lower surplus values less than 130 kg/( hm² · a)，but the other regions have higher values. According to the long calculated series of the N-surplus in the case-study region, the long-term N-surplus changes for the whole upstream area of the Lake Taihu are analyzed in the paper. At last, the authors upstream agricultural land.

Abstract:Investigation on surface runoff and associated mass transport for Xitiaoxi catchment is of significant importance as it is one of the major catchments of Lake Taihu basin. Outcomes from this investigation help understand the dynamic changes of hydrology and water quality of lake Taihu，and are also useful in carrying out similar research work on other catchments of lake Taihu basin. As the first step, this paper presents the construction of a surface runoff model for Xitiaoxi catchment using a conceptual model, LASCAM. The model is well calibrated using daily runoff data from 1968-1988 from 2 monitoring stations within the catchment. The modeled daily and annual runoffs match well with the observed ones. The model indicates that saturation excess runoff is probably the dominant process for the catchment. Water storage in near-stream shallow saturated soil has high correlation with daily rainfall, while water storage changes in deep aquifers demonstrate an annual change period，showing a rising level for wet seasons and a declining level for dry seasons. The findings are helpful for further refining the runoff model and constructing nutrients transport model as the next step.

Abstract:Badain Jaran desert lies in the northwest of Mongolia. In the eastern desert, the coexistense of lots of lakes surrounding big immovable sand dunes, the peculiar influences of wateriness inside the sand dunes and ascending springs in the lakes have been found. Similar conditions occur in its north and northwest areas. In this paper, combined with hydro chemistry factors, a method similarity priority ratio is firstly applied to analyze some water samples of different positions in Badert Jaran desert and its surrounding areas. And a result that it has a good hydraulic relation on the snow water of Qilian Mountain and lakes in the desert and ground water in some surrounding areas has been given.

Abstract:According to the analysis on basin，regional and urban flood control projects in Taihu basin, the basin flood control system mainly consist of 11 key engineerings and its function is to ensure safety of Taihu basin under the design flood conditions. The critical value of flood loss to equal 0. 2%-0. 3% GDP of the basin is regard as a index judging and controlling basin flood disaster. Based the meaning of flood control standards for Taihu basin,relationship between space-time distributing of design storm and planning of the flood control system are analysed. Lastly, the practical flood control standards of the basin is discuss and some suggestions are put forwarded to increase basin flood control capacity.

Abstract:To detect the influences of different temperatures on Microcystis aeruginosa dominance, this experiment researched competition between Microcystis aeruginosa and Chlorella pyrenoidosa under different temperatures by flow cytometry, cell density ratio and chlorophyll-a fluorescence intensity in two species of algae cell were measured. Results displayed under this experimental condition Microcystis aeruginosa dominance became more evident together with temperature rised( 18℃,25℃ and 32℃ ). Higher temperature enhanced chlorophyll-a fluorescence intensity in Chlorella pyrenoidosa cell but reduced chlorophyll-a fluorescence intensity in Microcystis aeruginosa cell. This experiment indicated under suitable light and high nutrition salt condition, higher temperature promoted Microcystis aeruginosa dominance obviously and influenced water bloom forming.

Abstract:Genetic diversity and genetic differentiation between Coilia ectenes and Coilia ectenes taihuensis have been investigated at the mtDNA level. Sequences analysis of cytochrome b (cytb) gene segments amplified by PCR was used. Five different haplotypes were detected between the populations studied. The haplotype diversity of C. ectenes and C. e. taihuensis were 0.9000 and 0.7000，respectively. The nucleotide diversity of C. ectenes and C. e. taihuensis were 0.3763% and 0.4301%, respectively. An hierarchical analysis of molecular variance (AMO-VA) showed that very low levels of genetic partitioning, with 0.00% of the total variation attributed to between population differences, and lack of genetic structure. Our results supported that C. e. taihuensis is a geographical population of C. ectenes; their difference has not risen to subspecies level.

Abstract:The aim of this study was to detect the effect of different water temperature ( lO℃, 15℃, 20℃, 25℃) on oxygen consumption rate( OCR) and ammonia excretion rate(AER) of Hemibarbus maculatus Bleeker and expounded the influence on water quality by oxygen consumption and ammonia excretion of Hemibarbus maculatus Bleeker. The results demonstrated that the effect of body weight and water temperature on OCR and AER was significant, but no significant effect was shown on their combination； The relationship between OCR ( R_O ) AER ( R_N) and body weight( W) could be expressed as R_O = aW^b and R_N = cW^d. The significant increasing of OCR and AER followed by the rise of water temperature within the range from lO℃ to 25℃, decreasing with the increase of body weight；The linear regression relationships of OCR( R_O) with temperature and body weight could be described as R_O = 0.008T + 0.022W-0.003, and AER( R_N ) could be illustrated by R_N = 16. 7T + 0.741W-0.44, the multiple relation coeffreient r were 0.967 and 0.937 respectively; the ratio of R_Oand R_N was 10.31-28.08, which indicated that protein and fat were the main energy objects of Hemibarbus maculatus Bleeker.

Abstract:Macrozoobenthos community plays an important role in material cycle and energy flow in riverine ecosystem. During the period of June，2003 to June 2004，an investigation on the life cycle and production of the dominant species of macrozoobenthos community in a second-order river of Hanjiang River Basin was carried out. From the upper to the lower reach of Heizhuchong stream, we chose six types of habitats to collect quantitative samples. Station 1 (SI) lied in the middle of the stream with big round rocks in the upper reach，station 2 (S2) was in the inner part of a weir with cobble substratum，station 3 (S3) in the middle of a peacefully flowing section with gravel-sand bottom, station 4 (S4) at the side of the riparian with aquatic macrophytes and snags, station 5 (S5) in the middle of the riffle, station 6 (S6) at the lower reach with a sewage outlet ca 100 meters uppstream. At each station, four quantitative samples were taken with a 167um D-frame kick net or a Surber net, and the samples were sieved with a 167um net, sorted in a porcelain dish with naked eye. The specimens were kept in 10% formalin for later processing. The life cycle of the S. teritisum Dai et al. population was analysed by the monthly size-class frequency distribution, the cohort and annual production were estimated by size frequency method. The results showed that S. teritisum completed one generation for nearly 4 years，the reproduction mainly occurred in from middle August to middle October, and most of the senescent individuals died in February. The abundance of the population varied greatly during the year, probably due to the relatively smaller sampling area compared with the strong activity of motion of S. teritisum. Whereas, the variation of the biomass followed the same pattern of the abundance. The abundance attained its peak in September with 35 ind/m²，and biomass reached its highest level in June at 41.7 g/m². The estimated cohort production and cohort P/B ratio by size-frequency method were 605.2g/(m² · a) (wetwt) and 5.5，respectively； the annual production and P/B ratio were 151. 3g/(m² · a) (wetwt) and 1.4. The reason why the annual production of the animal in Heizhuchong Stream was the relatively higher was because of its high density. By analyzing its stomach content, the proportions of amorphous detritus, caridina，aquatic insect larvae, gastropods and vascular tissues were 45.4%, 10. 9%, 35. 6%, 5.7%, 8.1% . Therefore, the contribution rates of the above types of food to production were 10.84%, 18.21%, 59.49%，9.52%，and 1.94%, respectively.