Abstract:Being the basis of human society, freshwater aqua-ecosy stem is suffering of gradual degradation in many regions of the world.Most fresh water lakes and river net in plain are shallow waters in China.There are abundant higher aquatic plants and associated fish, shrimp, shellfish, mussel and other macro-hydroorg anisms.Possessing prolif ic biodiversity, these waters were selected as drinking water sources for many cities and tow ns in the history.But at present, these clear waters in most cases have been degenerating into "desert-waters" in defectof macrophy tes but dominated by phy toplankton and other microorganisms, along with the increase of pollutant loading.The loading of pollutions into surface water systems was increased gradually in comparison with that before a couple of decades ago.How to restore the degenerated aquaecosystem for a sustainable and healthy aquaecosystem under enhanced pollutants loading is the issue of great theoretical and practical importance.The water quality problem is a problem of ecosy stem.The target, measures, approaches, key technologies and the feasibility for remediation of the aquaecosy stem were reported in this paper according to the research and experiment results on Physico-Ecological Engineering(PEEN) in fresh waters of China since 1990 [1].The main conclusions are as follows:1)The main aim for harnessing the surface waters is remediation for sustainable healthy aquaecosystems.2)The main measures for harnessing the surface waters are to carry out the Physico-Ecological Engineering-(PEEN)and Bio-Envio ronmental Enterprise-(BEE)in combine with harnessing the pollution sources.3)The main approach for realizing the aim is "sparks ex ploding" starting from local to larger areas and to the whole catchment.4)The key momentums for realizing the aim are 4M:Macrophyte, Macro bio-imitation, Microo rganism, and Management.5)The beautiful and bright future with green mountains, clean waters, high level waters, high level civilization and abundant resources in harmony developmentof social economy and environment might be realized come-atable.

Abstract:The species composition, distribution, neoteny phenomenon, ecological characteristics and transplantation status of salangids in China were reported.The ecological management principles of the fishes for transplantation including economic, geographical, biological and ecological principles were discussed.

Abstract:Fresh waters contained ⁸⁷Sr/⁸⁶Sr information are related to the st rontium isotopic compositions of different rock types which they flowed across.The ratios of Sr/Ca in lake are usually a proxy of salini ty, which can reflect the variation in levels of lake.So, the Sr geochemistry of shells from basin sedimentary can be used to derive a record of the different resources of waters inf low to the basin, and of the changes of water in basin.A study on example of the 28th bed of Xiaodukou sect ion, Nihewan basin, implies that the st rontium geochemistry of shell is a desirble method of palaeohydrological restoration, and further indicates it would be a good future matching with carbon and oxygen isotopes and other trace element geochemisty.

Abstract:Here we displayed the results of trace elements and stable isotope in shell Gyraulus sibirica continuously preserved in the sediments of Xincuo Lake, Eastern Tibetan Plateau, in the past 50 years.By coupling these indexs and inst rumental meteorological data in its basin, we probed quantitatively modern climatic signals recorded in these indexes to build relat ive function relations.The results showed that gastropod shells in Xincuo Lake were formed in summer half year, so that trace elements, stable isotope in shells just recorded the climatic signals of the summer half year instead of those of the whole year, Mg/Ca ratio and δ¹⁸ O pro xy had a certain correlativity with summer half year air temperature, in which δ¹⁸O proxy was more sensitive with variability of δ¹⁸O to temperature d δ¹⁸O/dT 1.64‰/℃;As to Sr/Ca ratio and δ¹³C proxy, especially Sr/Ca ratio, there had a close correlation with summer half year precipi tation, in which the variability of Sr/Ca to precipitation d (Sr/Ca)/dP is -0.045/mm.

Abstract:Zige Tangco (32°00'-32°09'N, 90°44'-90°57'E, 4560a.s.l.), located in Central Qinghai-Tibetan Plateau, is an endo rheic saline lake.As no instrumental data were available in the basin, three nearby stations, i. e. Amdo, Naqu and Bangoin, were selected for lake evaporation estimates in Zige Tangco.Meteorological observations from three above-mentioned stations as well as radiation data from Naqu were used for Penman equations approach.During 1958-1998, a yearly-mean lake evapo ration of 925.1mm was calculated, ranging from 791.9mm (in 1983) to a maximum 1111.5mm (in 1975).Further 5-year running average resuls revealed that 2 high-level stages and 1 low-level stage were dominant in the past 40 years, and an ascending trend was obvious, though fluctuating.

Abstract:Based on considering the variation of vertical coefficient from bottom to surface, a quasi-3D numerical model was put forw ard to calculate the wind-driven current, and was applied in Taihu Lake under steady and unsteady winds, respectively, the resuls were satisfactory.Comparitive studies showed that the influence of the variation of vertical coefficientof eddy viscosity along the water depth is lit tle to the computation resuls of surface elevation, but it is great to the computation results of the velocity profile and the bed shear-st resses.Therefore, it is needed to consider the variation of vertical eddy viscosity coefficient to simulate the 3D wind-driven circulation in lakes for better simulation.

Abstract:Luomahu Lake is a seasonally shallow lake in the northern plain of Suqian City, Jiangsu Province, with an area of 375 km² in 1998, and an average depth of 2.35 m.Based on investigations of possible sources of nitrogen, phosphorus from the basin as well as nutrient outputs in the Luomahu Lake basin, 1998, some estimates are drawn as follows.The total nutrients inputted to the lake are nitrogen 15764.78 t/a and phosphorus 10335.53 t/a, coming separately from its inlets (nitrogen 13598.05 t/a, phosphorus 942.35 t/a), land runoff (nitrogen 25.04 t/a, phosphorus 4.77 t/a), cage aquaculture and artificial food (nitrogen 304.05 t/a, phosphorus 48.06 t/a), release from the sediments (nitrogen 1170.90 t/a, phosphorus 12.64 t/a)and atmospheric precipitation (nitrogen 666.74 t/a, phosphorus 27.71 t/a).The total nutrients drained are nitrogen 14232.13 t/a and phosphorus 813.90 t/a, i. e. from output through rivers (nitrogen 12915.74 t/a, phosphorus 701.56 t/a), harvest of fish (nitrogen 223.12 t/a, phosphorus 57.72 t/a), harvest of aquatic plants (nitrogen 120.00 t/a, phosphorus 21.00 t/a), irrigation and factory utilization around the lake (nitrogen 973.27 t/a, phosphorus 33.62 t/a), respectively.The nutrient balance results shows that the main input and output ways of nitrogen and phosphorus are rivers, the nitrogen input by rivers occupies 86.3% of total input and phosphorus input 91.0%.Nutrient deposit is smaller, with nitrogen deposits 205.47 t/a (deposit efficient 0.097)and the phosphorus deposits 199.95 t/a (deposit efficient 0.214).The nutrient load is much higher, i. e. nitrogen is 42.04 g/(m²·a)and phosphorus 23.76 g/(m²·a).Nevertheless, the concentrations of nitrogen and phosphorus in lake increased quickly in 1998.The main countermeasures of eutrophication controlled are reducing the nutrients from rivers and protecting the aquatic plants in Luomahu Lake.

Abstract:A 70cm-sediment core was collected from West Lake, an eupert rophic lake, Hang zhou, P.R.China.Samples were studied by the fraction procedure of Hieltjies & Lijklema (1980) to obtain the phosphorus fractional profiles.In the sediment, the largest partof phosphorus (30%-70%)was bound to calcium, while Fe & Al bound P (NaOH-rP)and loosely absorbed P (NH₄Cl-rP)holding about 16%-40% and 0.6%-10% separately;labile phosphorus comprised of 20%-40% of the particulate phosphorus at the time of deposition.The vertical distribut ion of P fractions and labile phosphorus were similar with that of total phosopho rus.In the deep partof sediment the contents increased with the decrease of depth;the peaks all appeared in the layers of between 10-30cm;while in the upper layers a decline with depth was presented.

Abstract:Phosphate sorption isotherms were determined for representative upland and paddy soils in Taihu Lake watershed.P desorped from the soils were also studied by successive extractions with iron oxide-impregnated paper st rips.Although the averaged P sorption maxima of upland soils derived from Langmuir sorption plot was a lit tle higher than thatof paddy soils the po tential of P loss from upland soils to waterbodies was greater because upland soils usually had a much higher P level.The Deg ree of Phosphorus Saturation (DPS), an integrated expression of soil P level and soil sorption capacity, can give good estimate of the amountof P desorped from soils so it can be used as a reliable index to assess the potential of soil P loss via leaching or surface runoff.

Abstract:Phosphatase in sediments in Lake Donghu, Wuhan can be classified as alkaline phosphatase, showing a higher activity at alkaline pH ranges.The kinetics of alkaline phosphatase exhibited a distinct spatial heterogeneity in sediments of Lake Donghu and Yanxihu, which is not significantly correlated with the concentrations of soluble reactive phosphorus in interstitial water, overlying water and surface water.Furthermore, it varied greatly in vertical profiles, and peaked both at surface and in a middle layer (8-12 cm beneath the surface).The latter added a new dimension in which P cycling mediated by some biochemical mechanisms is active.

Abstract:According to the resources and culturing situation of Chinese mitten crab (Eriocheir sinensis) of China, this paper analyzed present problems concerning the culturing of crab fingerlings, adult crab and the aberrance of idoplasm.Meanw hile, to meet conservation demand of the species character, the author discussed some question on the contamination of heredity and the intermix of idoplasm, and put forw ard some suggestions for the conservation of Chinese mitten crab.

Abstract:Sediments is an important sink and sources of pollutants and nut ritive elements, such as heavy metals, organic toxicants, phosphorus, nitrogen, and carbon.In the sediments, organic matter is the key factor to control the environmental behaviors of these substances.In this paper, the studies in the geochemistry behaviors oforganic matter in sediments, and its effects on the behaviors of heavy metals, organic toxicants, phosphorus and carbon in sediments were review ed.The effect of organic matter on the eut rophication of fresh water, ecological tox icology of heavy metals and organic compounds, and the release of greenhouse gas from fresh water were discussed, too.

Abstract:CBERS-1(China-Brazil Earth Resources Satellite No.1)is the first earth resources satellite of China.Its successful emission and running overcome the long-term shortage of depending on foreign satellite data.This paper briefly introduces the types of sensor of the CBERS-1.Then, based on the image of Nanjing area on 1999.11.29, the water system information, especially lake information is extracted and analyzed according to the characteristics of this area. Furthermore, the environment problems of this area facing with are fully and accurately analyzed.

Abstract:M. aeruginosa Kutz is harmful to ecological environment of lakes.The algae in water bloom of Dianchi Lake was isolated with methods of dilution and agar solid-media culture.It was found that after purification, grow thing rate of the algae was raised by 5 times in liquid culture media.When extracting total DNA of the algae, if the cells were pre-treated by alcohol + ether (1:1), their gelatinous sheathes were broken and the production of total DNA increased by 3-4 times.The improvement of DNA ex traction is useful to molecular biology studies of the algae.