Abstract:Watershed ecology is an intersect discipline of hydrology, limnology, ecosystem ecology, landscape ecology, eco-economics and eco-management.Because of the watershed ecology's significance to watershed sustainable development, people at tach importance to it increasingly. About watershed ecology, we should pay more attention to these theories and concepts as follow s:society-economy-nature muti-ecosystem, river continuum concept, ecotone theory, hierarchy theory, pattern-process-scale, and watershed informat ion system.Now, the t rends of watershed ecology concentrates on five point s which are watershed physical process, bio-service, structure and function of watershed ecosystem, watershed environment and watershed management.In East China, there is an important region, which is Taihu Lake basin.10 percent of Chinese GNP comes from this 0.4 percent of Chinese territory.But frequent flood disaster and increasing water pollution confront regional sustainable development.Based on the deliberation watershed ecology, the significance of watershed ecology to flood disaster control, water pollution control and sustainable development in Taihu basin are discussed in this paper.It is suggested that the study and application of watershed ecology should be an effective approach to solve those problems, and that it is necessary to deepen the research.

Abstract:There has been a g rowing concern in recent years regarding possible harmful effect s to man and other living o rganisms of pollutant organic chemicals released into the environment as a consequence of human activities.Polycyclic aromatic hydrocarbons (PAHs)are one of the mo re significant classes of pollutants, w hich give rise to this concern.This concern arises primarily from the fact that some PAHs generated and released to the environment by human activities have show n to be carcinogenic to mammals.Many researches have been done about the properties of PAHs. PAHs of different molecular weights o r structures vary substantially in their behavior and distribution in the environment and their effects on biological systems.PAHs can be formed mainly in three ways:high temperature pyrolysis of organic materials, low to moderate temperature diagensis of sedimentary organic material to form fossil fuels, and direct biogenesis by microbes and plants. In this paper, the ex tractable lipids were isolated using Soxhlet extraction method in the East Taihu Lake sediment, the ex tracts were fractionated on an activated SiO₂/Al₂O₃ column.The aromatic compounds were w ashed in benzene.Phenanthrene series, one group of important polycyclic aromatic hydrocarbons were analyzed and identified by the GC-MS instrument.The sources of Phenanthrene in Taihu Lake sediment were discussed.Phenanthrene series w ere also found from the aquatic plants with similar composition pattern with that in the East Taihu Lake sediment.This is the first time that aquatic plant s have been singled out as the major source of phenanthrene series in the East Taihu Lake sediments.

Abstract:The δ¹³C values of the dissolved inorganic carbon (DIC), the org anic matter of surface sediments and the aquatic plant cellulose were measured in Lake Caohai, Guizhou Province.The δ¹³C values (vs PDB)of DIC, o rganic mat ter of surface sediment s and aquatic plant cellulose, range from -3.70‰ to -10.60‰, f rom -20.50‰ to -21.60‰, from -16.10‰ to -17.40‰ respectively.Then A simple carbon cycle model is built through the mass balance calculation.All results indicate the photosy nthesis-respiration of aquatic plants and the decomposit ion of organic mat ter are the decisive factors to the carbon isotopic compositions of the lake system as Lake Caohai, which is a shallow, oxygen-rich lake with abundant aquatic plants.

Abstract:The area of lakes in Qinghai-Tibetan Plateau is one of the largest and the highest lake district in the world, most of which lie on the north Tibetan Plateau (Qiang tang Plateau)with an average altitude of more than 5000m a.s.l.In the summers of 1997 and 1998, we investigated the hydrog raphic features of Sêrling Co, north Tibetan Plateau.The hourly maximum temperature of epilimnion occured at 4:30 a.m.and the minimum w as at 7:30 p.m.The maximum temperature of epilimnic shallow region could reach at 21.2℃ and the minimum was 11.0℃ in June.The range of daily mean temperature of epilimnion was only 5.6℃ and was larger than the difference of that w as co rrespo ndingly tested among different regions in Sêrling Co.The water pH value of epilimnio n in the lake varied from 9.19 to 9.66.However, the range of hourly pH value in shallow region was only 0.15 and the maximum occured in the early morning, w hich differs from other lakes such as the lowland lakes in east China.The dissolved oxygen v aried f rom 4.62 mg/L to 5.12 mg/L and the changes among dif ferent deep regions w ere only 0.03-0.35 mg/L in Sürling Co.Hourly gradient of dissolved oxygen of epilimnion varied f rom 4.85 mg/L to 5.59 mg/L in Jiang dongrurui (aquene of Sürling Co), 4.72-5.35mg/L in the mouth of Boquzangbu and 4.54-5.93 mg/L in the low er reaches of Boquzangbu.The hourly minimum of dissolved o xygen in Jiangdong rurui and Boquzangbu occured at 4:30 p.m., and in the outlet of Boquzangbu at 7:30 a.m.The times that maximum dissolved oxygen observed were so different and occurs respectively at 10:30 p.m., 7:30 p.m.and 10:30 a.m.in the regions above-mentioned respectively, which proved that the dissolved oxygen could be influenced by water temperature and hydrobiological activities.The hourly salinity of epilimnion in the lake varied f rom 1.6-2.2% and the maximum occured at 4:30 to 7:30 a.m.In the inland water bodies of north Tibetan Plateau, i t is obvious that there is a concentrical tendency of salinity from st reams to lakes and from running water to still water.The dist ribution of fishes is correlative wi th the salinity of waters.Consequently, fishes disappear and are replaced by salinella with the increasing salini ty in water bodies.

Abstract:The checking and accepting standards of Hy drological Data Acquisition System (HDAS) const ruct ion vary with its work mode.The analytical methods of HDAS reliability could be different under different structures.The reliability of the built-up of HDAS in Taihu Basin is discussed in this paper by means of probability analysis.The reliability is better to measure the polling-answering system with memory than the accessible rate of a monthly average, and the reliability has been influenced by the sy stem structure.It is of great significance that the reliability of HDAS is studied by the probability-stat istics on the draf t of checking and acceepting standards of the system construction and the st ructure design of HDAS.

Abstract:The phosphorus release and abso rption of surficial sediment s in Taihu Lake w as studied under simulative disturbing conditions.The results show ed that the sediment release effect s of the Wulihu Lake and the Meiliang Bay w ere not as remarkable as expected.Under lower disturbing intensities, the release processes were not obvious.As the disturbing intensity became greater, an obvious release process w as observed.The t ime needed in getting maximal release was distinct because of the different phosphorus constitutions. The phosophorus abso rptio n w as obivous under simulative condition.The phosphorus concentrations of upper water of surficial sediments in Taihu Lake w ere reduced from 0.229mg/L and 0.215mg/L to 0.05mg/L and 0.013mg/L under disturbing condition of 100rpm and 25℃, respectively.The experiment show ed that the abso rption intensity w as much g reater than the release intensity in higher phosphorus concent ration of upper water of surficial sediment.Under 25℃ and moderate disturbing intensity (100rpm), w hen the initial phosphorous concentration w as 1.01mg/L, the absorption capacity of surficial sediments of the Meiliang Bay and the Wulihu Lake could be up to 0.042mg and 0.050mg phosphorus per gram dry sediment.This huge absorption capability of surifical sediment may play a positive role in phosphorus buffering in shallow lakes.

Abstract:In August, 1999, w e investigated Golmud River-Dabsan Lake field and sampled systimatically from surface water along the river from the source-Kunlun Moutian to the end-Dabsan Lake.After that, we analysed the principal chemical composition of the river water and calculated some parameters such as mineralization, and types of hydrochemistry and so on.According to the fluctuation of mineralization along the river from south to no rth, five different reg ions may be distinguished:(1)region Ⅰ:gobi;(2)region Ⅱ;alluvial-pluvial fan;(3)region Ⅲ:alluvial-pluvial plain;(4)region Ⅳ:lacustrine plain;(5)region Ⅴ:brine lake, among which region Ⅱ can also be divided into two sub-regions:(Ⅱ₁)the part of w est river of alluvial-pluvial fan and (Ⅱ₂) the part of the east river of alluvial-pluvial fan.From region Ⅰ to region Ⅴ, the mineralization increased as a w hole.There appears an abno rmal high value in sub-region Ⅱ₂, due to the disturbing as the shallow g round w ater has relatively higher salt content.The g round water level is so shallow as to reach the surface of earth, a great amount of salts w ere dissolved from soil by shallow phreatic water and then flowed into river, which made primitive fresh river water became half brine, the type of hydrochemistry changed suddenly from C_Ⅱ^Na to C_Ⅲ^Na.From this region tow ard the lake, the river discharge had no great change except for region Ⅲ.The hydrochemistry of region Ⅳ w as nearly the same as in the region Ⅲ except that the mineralization w as somew hat lower.As fo r region Ⅴ, the Dabsan Lake became a brine lake due to its long histo ry of evolution.Origionally the region Ⅴ was a play a as a dissolution basin.Under the condition of ex treme arid climate as w ell as high evaporation a brine lake came into being. Generally, the hydrochemistry of west river w as more stable than that of the east river.The adjustment capacity of west river w as better and does no t easy to be disturbed by other water.In the long run, future harnessing of water resource should lay stress on the part of the west region, mean while some measures should be taken to keep the half brine water of east river from any further salilization.

Abstract:Plasma gonadotropin (GTH)levels during immature, mature and ovulated periods and effects of gonadot ropin-releasing hormone (GnRH)and dopamine on GTH secret ion of in vitro pituitary cells of rainbow trout were investigated.Plasma GTH levels increased wi th gonadal development.The different effects of sGnRH and cGnRH on GTH-Ⅱ secretions of pitui tary cells in vitro f rom immature, mature and ovulated periods of rainbow trout w ere observed.GnRH antagonist did not change GTH-Ⅱ contents under the absence of sGnRH w hile GnRH antagonist suppressed dose-dependently GTH-Ⅱ secretions of pi tuitary cells in combination with sGnRH. Dopamine also did not affect GTH-Ⅱ levels under the absence of sGnRH, while G TH-Ⅱ secretions of pituitary cells were enhanced w hen the dosage of sGnRH was increased with the presence of constant levels of dopamine.In addition, sGnRH and cGnRH had no effects on GTH-Ⅰ secretions.These result s provide some basic informations for modulating the spontaneous release of GTH-Ⅱ and cont rolling fish reproduction.

Abstract:Combined with culture of juvenile crab in Chongmin experimental stat ion, a comparative experiment w as conducted on the precocious conditions of Yangt ze population and Liaohe population of mit ten crab (Eriocheir sinensis).The first catched date of Yang tze population was Aug.15, and Liaohe population w as Aug.20.From that time, the number of catched prococious crab of both populatio n climbed rapidly and reached the peak in Oct.The gonad of Yang tze population developed earlier than that of Liaohe population.In precocious population, the mean w eight of Liaohe population w as lower that of Yang tze population and sex difference in weight had no signif icance (P>0.05), but the number of male crab was much higher than that of female crab (P>0.05).

Abstract:This study deals wi th the relation between algal biomass and 15 environmental factors such as w ater temperature (WT), suspend solids (SS), Secci-depth (SD), DO, COD, pH, NH₄-N, NO₂-N, NO₃-N, TN, PO₄-P, TP, Alkalinity (ALK) based on the monitoring data from 1992-1999 in Meiliang Bay, Lake Taihu.The stepwise multiple regression statistical method was used to calculate the relation between algal chlorophyll-a (Chla), total algal biomass (TB), Microcystis biomass (MB)and these environmental facto rs.The results show ed that WT and TP were the most significant related factors to TB while WT, NO₃-N and TN were the most significant related factors to MB.These can be used to predict the blue-g reen algal bloom in the bay.

Abstract:Organic carbon isotopic records from lake sediment s are valuable pro xies used to indicate g lacial-interglacial change in atmospheric pCO₂, major changes in catchment vegetation, lake level fluctuations, and variations in regional temperature.While factors af fecting variations in organic carbon isotope (δ¹³C_org)are numerous, predominant control(s)on the shif t of δ¹³C_org value w ere of ten found out with the aid of evidence from o ther investigations on the lake sediment s such as paleolimnological, geochemical, sedimentological and palynological studies, as well as molecularisotopic stratig raphy.Environmental explanation models (EEMs), proposed by investig ators in the previous researches for those long-term isotopic records showing different curve patterns, are reviewed. Recognition and clarification of source materials of organic matter (OM)buried in lake sediments and of possible changes in organic source materials in the past are fundamental aspects and important for the environmental interpretations of δ¹³C_org records.OM contents, organic carbon to nitrogen (C/N)rat ios, hy drogen index (HI), petrog raphic examination of organic remains in lake sediments of ten provide useful information on organic productivity, origin, maturation, and diagenesis.Hence, they should be presented, if available, alongside w ith δ¹³C_org record.In this way, EEMs can then be properly applied, otherwise new EEMs may well be provided.In addition, identification of individual biomarkers of ten provides indication of specific terrestriall, aquatic, and bacterial sources of organic mat ter in lake sediments.New carbon iso topic signals ref lecting Glacial/interglacial environmental change may well be indicated by molecular-isotopic stratigraphy.Long-term δ¹³C_org records from many interested lakes in China aw ait us to investigate, depending largely on bottom sediment cores from those lake centers become available.These records have g reat potential for the researches of the past global changes.

Abstract:Zoobenthos are one of the majo r ecological g roups in fresh waters.They play an important role in nutrient cycling and energy flow in ecosystems, and are very useful food resources for fish. Zoobenthos are also used as biological monitors of the envi ronmental health of lakes and rivers. Theo ries and methods of the secondary production of zoobenthos were reviewed w ith emphasis on the calculation of secondary production, P/B coefficient and factors to affect secondary production.In addition, this paper also presents new advances including modelling of the secondary production and construction of benthic food web.

Abstract:A flux chamber technology can be used to measure the mercury flux be tw een the atmosphere and the lake surface in area of mercury emission.Measurements have been performed ov er the Hong Feng lake.the measured flux es (water temperature 20-24℃)w ere within the range 89-196(ng/(h·m²))(average 123(ng/(h·m²)).Measured fluxes were hig her in day time than in nighttime.Mercury fluxes are correctional with light emission as w ell as Mercury contents in sediments.

Abstract:The activity of ²¹⁰Pb and ¹³⁷Cs of lake sediments, namely Y2 and G, respectively from Ardley Island, Antarctica have been measured.According to the profiles of ²¹⁰Pb and ¹³⁷Cs activity, we used CRS mo del to date the G lake, which spans about 134±43 years.Base on the dating, we estimate the velocity of deposition.The increased sedimentation rates and the inventories of ²¹⁰Pb and ¹³⁷Cs as well as their flux being higher than the atmospheric deposition could be reasonably attributed to the supply of agreat amount of ice-melt water.