Abstract:This article is written to celebrate the 10th anniversary of the Journal of Lake Sciences. With emphasis on biological aspects, the author first gives a brief review of the publication of the journal in past decade, indicating that obvious advances have been made not only in expanding the scope of the journal, but also in heightening the standard of the papers it published. The steady increase in contributors also mirrored the progress of the journal. Secondly, the author presents some suggestions for improving the editorial work of next period, so as to enable the journal to synchronize with the rapid development of science and technology in the coming century.

Abstract:The highest water level of the lower reaches of the Yangtze River in the area of Jiangsu Province is continuously higher and its duration is obviously longer than before during the last decade. Therefore, the flood control became heavier and heavier, the regulation of the Yangtze River is payed the important attention by central and local government. In the paper, the heavy flood in 1998 is compared with that in 1954, based on data of practical measurements of Datong Hydrologic Station in the main channel and others in its down stream. The variable regularities of the average flood volume, mean of the highest water level, mean of the highest water and the average days when the water level is over the warning water level for flood control in down stream from the 1960s to the 1990s are discussed. Through the analysis of such factors as the water volume from upper and middle reaches of the Yangtze River, the tide from East China Sea, etc., the reason of frequent occurrences of high water level in the lower reaches of the Yangtze River is approached.

Abstract:Concept and the present situations of polders in the Taihu lake region are introduced in this paper. Polders have been built to defense floods effectively, but it has made the drainage of basin not smooth. Built polders have effects on the flood regime of Taihu Lake region, i.e. (1) The areas of water surface and capacities of store water are reduced; (2) Natural water networks are changed; (3) Run-on and runoff are affected by human activities, the increasing of pump power made runoff time much shorter than before. Based on the analysis, some methods of flood control in polders are given.

Abstract:Two plateau lakes (Lugu Lake and Erhai Lake) with different conditions are selected to show 210Pb geochemical behavior. ²¹⁰Pb and ¹³⁷Cs vertical profiles in sediments are measured by the Multichannel Analysis System (Caberra 100) in order to attain creditable sediment accumulation rates. By the Fe-Mn circulation, ²¹⁰Pb_ex vertical distribution in the sediments of Lugu Lake and Erhai Lake shows three types of distribution characteristics. But this has no influence on the ²¹⁰Pb_ex dating result. Sediment accumulation rates of Lugu Lake and Erhai Lake are 0. 050 -0.051 g·cm a and 0.044 -0.045 g· cm^-2a^-1 respectively by ²¹⁰Pb_ex method which repsents the average sediment accumulation result on 100-year scale. The discrepancy between the ¹³⁷Cs vertical distribution characteristics and the depositional fluxes is probably caused by the Cs diffusion in early-diagenesis process. However, the Cs diffusion does not change the location of Cs peaks. Sediment accumulation rate of Lugu Lake is 0. 045 土 0. 004g · cm^-2a^-1 by ¹³⁷Cs time marker (1964), and that of Erhai Lake is 0. 048 ± 0. 003g·cm^-2a^-1 (1964), 0. 047 ± 0. 002g-cm^-2a^-1(1975), and 0. 046 ± 0. 005g· cm^-2a^-1(1986) respectively which reflects the average sediment accumulation result.

Abstract:Aha reservoir, 6 kilommters away from southwest Guiyang City, Guizhou Province, is major source for drinking water of Guiyang City. Normal stage of this reservoir is 1108. 0 m; reservoir capacity 44. 5 million m³; and the water depth 26m. The dead stage and reservoir capacity of dead water are 1090m and 2.7 million m³ respectively. As an artificial lake, seasonal oxygen shortage is one of vivid characteristics of Aha,reservoir polluted by waste water containing Fe, Mn from coal mine. Results from years measuring of vertical water column of 20m depth in different seasons show that Fe and Mn distributions vary with different seasons and different temperture strata of water, and the vertical water temperature is in isothermal status from winter to earlier stage of spring, during which concentration of Mn and Fe in water is less than 0. 01 mg·L^-1 and 0.05 mg·L^-1 respectively. During summer and autumn, reservoir will be stratified according to different temperatures. Upper stratum is in oxygen rich status, with Mn and Fe concentration of less than 0. 1 mg·L^-1 and 0. 3 mg· L^-1 respectively, and the middle and lower strata are in status of low pH, oxygen shortage or lower oxygen, at which, Fe concentration is more than 0. 3 mg·L^-1 while Mn concentration is as high as 1.086 mg.L^-1，which is indentified to be closely rele-vant to oxidation and reduction reaction of high concentration of Fe(166000 mg · L^-1) and Mn (18800 mg·L^-1) contained in the reservoir sediment. The study provides a guideline of pumping at the optimum depth according to the optimum qaulity of water for water plant.

Abstract:The impacts of human activity on Erhai Lake and their countermeasures were analysised from 1996 to 1997 in view of the deterioration of ecological environment. First, the limitation of lake resources and fragility of ecological environment wee noted after studying the background of geology and geomorphology as well as the conditions of hydrology and meteorology in the lake basin area. The major human impacts in the historical preiod involeved in the enhanced deposition, lake shrinkage and water level decline which were caused by lumbering, expansive utilization of land. Human activities in the past 50 years have damaged the lake environment seriously with the development of civilization. The successive low water level from 1980 to 1986 has lead to a disastrous consequences on Lake Ahoy. In recent years, over-exploitation of resources, industrial pollution, wide use of chemical fertilizer and discharge of domestic wastewater etc., have accelerated eu-trophication in the lake. Obviously, the intensity of human activity has surpassed the capacity of re-adjustment of the lake ecosystem. Hence, it is necessary to determine main functions of the lake in consideration of present conditions. In this paper, we suggest that tourism and supply of water be the main functions. Then, such measures as control of water volume balance, of nonpoint pollution, recovery of vegetation in the lake basin area and development of ecological agriculture should be adopted to protect the lake environment. Furthermore, human actively must he regulated in harmony with development of social economy and ecological environment through scientific administration.

Abstract:Parents fish of Taking fugu obscurus were collected for artificial reproduction in the lower reaches of the Yangtze River from 1995 to 1997. The sexual gland of female puffer can develop to the end of IV period through treating with LHRH-A. The female puffers which the sexual glands have developed to the middle of W period could be induced spawning through in jecting hormone. The hormone for inducing spawn of the experiments is LRH-A、HCG and PG. At the temperature of 16-21 ，the time of effect is 6-86 hours, the average rate of spawning is 84.0%, the aver-age rate of fertilizing is 61. 8%, the average rate of hatching is 51.7%.At the water temperature of 20C°, the time of embryonic development is 154 hours.

Abstract:In this paper, we studied the growth of S. platensis in mimic Pb²⁺ polluted environment with different concentration from 10 to 80 mg·L^-1. The results showed that the growth rate of S. platensis was inhibited by Pb2+ above 20mg·^-1, S. platensis yellowed and died with Pb²⁺ concentration increasing and time going. The solvable protein, phycocynin and the ratio of phyco-cynin to carotenonid were all decreased. Each had a noticeable correlation with the Pb²⁺ concen-tration. Lower concentration of Pb²⁺ could decrease the photosyntheitc O₂ evolution of S. plat-ensis, yet the absorption spectrum of S. platensis was only seriously changed on high Pb²⁺ con-centration. Contents of O₂^- and MDA were also changed, each reached its maximum at 30mg·L^-1 and 40mg·L^-1. The activity of SOD was decreased obviiusly when above 20mg·L ^-1, but its relative activity was higher and quite steady at Pb²⁺ concentration from 20 to 50mg.L^-1.

Abstract:The population growth rate and ecological paramenter for Moina macrocopa under different three temperature (24, 28 and 32℃) and densities of Sacchromyces cerevisiae (0. 25 X 10⁶cell. mL^-1, 2.5 X 10 cell· mL^-1 and 25 X 10⁶ cell· mL^-1) were obtained. Results indicated that the in-trinsic increase rate (r_m) reached 1.048 d^-1 under temperature of 28℃, higher than 0.76d ^-1(24), and 1. 010 d^-1(32℃). Further comparisons showed that under culture conditions that density of S. cerevisiae of 2. 5 × 10⁶cell · mL^-1 and a temperature of 28℃, the r_m was maxi-mum, the productive period and life-span, of M. macrocopa longest, and the numbers of conceiv-ing eggs highest. Hence, the conditions of culture density of S. cerevisiae of 2.5× 10⁶cell·mL^-1 and a temperature of 28℃ were optimal for M. macrocopa production. Population accumulative culture experiments indicated a peak of population density of M. macrocopa was observed at the 7th day after inoculation. The peak instantaneous rate increase of population appeared at the 3rd to 4th day, so that a collection at the 5th day would be favored.

Abstract:This paper discussed the food species and its present frequency, intestine fullness, gill rake structure and food species, based on Protosalanx hyalocranius and zooplankton taken from Daoguanhe Reservoir from March 1995 to June 1997. It showed, with Protosalanx hyalocranius grown, that the distance between gill filters and the food size increased. There existed anegative relationship of food species in intestine and in the environment and a positive relationship of the intestine fullness and growth.

Abstract:The population growth of freshwater shrimp ( Macrobrachium nipponensis) was studied in Honghu Lake from May 1994 to June 1995. From March to June, the population is composed of shrimps born last year, and mean body length and weight increase monthly. From August to November, the population consists of ones born this year, mean body length and weight are the lowest in August and September respectivelly, afaterwards increase gradually till November. These show the course of alternation of generations.The growth period is devided into two evident stages. For the former stage (from August to November), the growth of males and females are both fit to Logistic curve and the equations are respectivelly：(♂)L_t =6.85/(1+ e^{0.318-0 2386t})W^t =7.50/(1+ e^{2 3854-0 3250t})(♀)L_t=6.25/(1 + e^{0 23720-0.1982t}), W^t =5.79/(1 + e^{2l95l-0.2371t}).For the latter stage (from March to June), the growth fit in von Bertalanffy's equation respectively：(♂)L_t=5.40[l-e^{-1 0600(t-7.3458)}], W_t=3.43[1 -e^{-1 0600(t-7.3458}) ]^3.2127(♀)L_t= 4. 76[1 -e^{-1.5635(t-5.6903})], W_t=2.43[l-e^{-05635(t-5.690,3}) ]³¹⁸⁸⁰,This report also deals with the method on studying the population growth of M. nipponen-sis t how to utilize rationally and protect effectivelly the resources of M. nipponensis.

Abstract:A study was carried to investigate the effects of precipitation-acidified water of Donghu Lake on the survival and reproduction of Brachionus bidentata under the condition of individual cul-ture. The experiment was conducted at 28℃ in a photoperial (L:D = 18:6) with light intensity about 500 lx. rhe rotifers were fed with ChLorella pyronoidosa at a density of 6. 0 X 10⁶cells · mL^-1，and the mediums were exchanged once twelve hours. The results show that when the roti-fers were cultured in unacidified water (pH8.4) of Donghu lake, the percentage of mictic females and the mean number of amictic eggs were 8.33% and 13.909, respectively; The intrinsic rate of the population was 0.076015 h^-1. Compared with the above results, when the media was acidi-fied to pH 6.5, 5.5 or 4.5，the numbers of amictic eggs increased to 18.778, 18.167 and 15.5 ind.，respectively; but decreased to 12.083 ind. at pH 3.5. The intrinsic rates of the populations at pH 5. 5 and 3. 5 increased to 0.08901 and 0.079684 h^-1, and no mictic females appeared, re-spectively. At pH 6.5 and 4.5, the intrinsic rates decreased to 0.069258 and 0.07354 h^-1, bui the percentages of mictic females increased to 25% and 16.67%, respectively. Between pH 6.5 and pH 3.5，Brachionus bidentata was acid tolerant.

Abstract:This paper first report the distribution and role of four nitrogen cycle bacteria in the artificial ecosystem of Taihu Lake. These nitrogen cycle bacteria include ammonifying bacteria, denitrify-ing bacteria, nitrobacteria and nitrovsobacteria, determined with MPN method. 1 he MPN values of denitrifying bacteria in the water covered by Alternanthera philoxeroides and Eichhornia cras-sipes are about 2-3 and 2-5 oraer-of-magnitudes higher than the water vegetated with other macrophytes and unvegetated water respectively. There is significant difference between them (P <0.01). The MPN values of ammonifying bacteria in vegetated water are markedly higher than that in unvegetated water. The MPN values of nitrosobacteria in vegetated water are notably higher than those in unvegetated water (P<0.01). The MPN values of nitrobacteria and ni-trosobacteria in the water vegetated with submerged plant are nigher than those in the water cov-ered by floating plant. The MPN values of ammonifying and denitrifying bacateria, nitrosobacte-ria are very dense in rhizosphere, and decrease from rhizosphere to outside.

Abstract:Abstract Photosynthesis of a cultured benthic blue-green alga Tolypothrix sp. was measured under light and temperature conditions using oxygen light-dark bottle method and ¹⁴C light-dark bottle method. Respiratory rates of the alga were also measured at different temperatures. Photosynthetic rates increased with increasing temperatures. Respiratory rates did not show significant differences among different temperatures. Photosynthetic rates were almost the same under light intensities lower than 400μEm^-2s^-1.Comparing the oxygen and ¹⁴C method, the photosynthetic quotient Q (moles O₂ per moles C) of Tolypothrix sp. in these experiments was about 1.11. The method for the measurement of photosynthesis of such kind of benthic alga was improved in this paper.

Abstract:The mature 0⁺ crabs, Eriocheir sinensis, hold the spawning migration and some of them have the mating behavor in freshwater lakes, and the sperm in the female spermathecum is observed in next March. The peak of mature 0⁺ crabs, activity arrives at October and next March. 79 mature 0⁺crabs (27 ♀, 52♂) were caputured from the 272 crab-holes in earth-ponds in March 1995. The new soft shells with distinctive spines and ridges were peeled from the dead female crabs in early July 1995. But the authors don't find the old shells taken off by crabs themselves.

Abstract:Epipelic algal community and phytoplankton community are two correlative communities in the same ecosystem of West Lake, Hangzhou. In the 1940s, Aphanothece stagnina was a dominate species in the epipelic algal community, occupying 98% -99% of the sediment in West Lake. Therefore forwarded a half centenary, following the eutrophication of the lake, the transparency of water decreased, and the decrement induced a corresponding succession of the epipelic algal community. The dominant species are changed from Aphanothece stagnina to Synedra herolinensis.The epipelic algal community in West Lake can be divided into 3 assemblages：(1) Synedra berolinensis Assem.： Distributed in Waixihu and Beilihu area with relatively high algal density, 302×104-575×10⁴ind·g^-1. Synedra berolinesis is a dominant species, occupying 41.2%-52. 8% of total algal number in the assemblages.(2)Fragilaria construens var venter-Syneclra berolinensis Assem.： Distributed in 3 lake areas which are located in the western part of the lake(Xilihu, Yuehu and Xiaonanhu). The algal density is 1/3 -1/8 of the first assemblage.(3) Aphanothece stagnian Assem.： Only exists in the inner lake on Santanyinyue island.

Abstract:Analysis of water quality and evaluations show that the Erhai Lake is in a mesotrophic state. According to eval-uations on some annual average state and on all lake nutrition types at some period of recent years, it is feasible that Erhai Lake now is assessed to the transition type between mesotrophic and eutrophic state. Compared with historical data, from the 1980s the pace of eutrophication was a little fast and the nutrients elements concentration increased gradually. Factors that result the changes are: (1) increasing of contaminants within the catchment; (2) lake being at low water level for a long time, and (3) unreasonable exploring of natural resources.

Abstract:Expounding the base and character of original Chinese Lake Database, linking up the progress of Information Technology and Geographic Information System, bringing forward the new concept of Chinese Lake Information System in the age of Internet, discussing the constructive model of lake information system based on WWW and service model based on Client/Server, and solving some key technique problems of the lake information system based on WWW.