Abstract:In order to explore main causes and dynamic mechanisms, the latest data of past sequences of solar radiation and volcanic dust are adopted in this paper to simulate the climate change during the Little Ice Age.The results show that the annual mean temperature decreases in Eurasia.The decreases in temperature vary with regions and seasons.The amplitude of decrease in temperature in high latitude is bigger than that in low latitude, and it is higher in winter than in summer.The decrease of annual mean temperature is from 0.2℃ to 0.4℃ in the region to the north of the Yangtze River.Climate in different monsoon region has different response to the changes of solar radiation and volcanic dust.The precipitation is decreased obviously in eastern and southern China, which is controlled by southeastern monsoon climate at present.The annual mean decrease is about 0.5 to 1.5 mm/d.While the precipitation slightly increases or remains almost unchanged in the vast areas which are controlled by westerlies and southwestern monsoon.The maximum annual mean increase is less than 0.5 mm/d.These results are mainly consistent with the historical evidences and natural records.

Abstract:Longgan Lake is located in the lower reaches of the Yangtze River.Based on the sediment pigments, total organic carbon, pollen, grains and susceptibilities, combining with ¹⁴C dating, the environmental evolutions were reconstructed since the Last Glacial Maximum.Before 15.0kaBP and during 10.0-6.3kaBP, the Longgan Lake was characterized by river deposition with lower productivity and higher susceptibility.During 15.0-10.0kaBP, Longgan Lake was formed initiated, as documented by obvious increase of organic production.The rudiment of the lake started from 6.3 kaBP, followed by the stable lake condition after 3.7kaBP.The wetland vegetation was extablished around the lake area after 3.3kaBP.It is necessary, however, to track the changes of sediment source, in order to study the mechanism of lake formation and evolution in Longgan lake, as well as the relationship between the lake and Yangtze River.

Abstract:The water quality of Taihu Lake has been declined for 1-2 level in the past decade.In 1990, 86.5 percent of lake water belonged to Surface Water Level 2-3 (GB3838-88)and was from mesotrophic to eutrophic, while 87 percent of them belonged to Surface Water Level 4 (GB3838-88)and under heavy eutrophication in 2000.Through analysis of the social-economic development and water environment change in the watershed, the author suggests that industrialization, urbanization as well as shifts of irrational agricultural production style and life quality improvements contributed greatly to water quality deterioration of Taihu Lake.Moreover, irrational management system, and the lack of environmental protection idea and capacity of sewage treatment are the fundamental reasons for water environmental deteioration in Taihu Lake.

Abstract:Qinghai Lake is an acid lake and located in Tengchong County, Yunnan province.Qinghai Lake is a crater lake with continuously acid groundwater supply, which is the geological foundation of the acid lake.We analyzed water, soil, sediment and biological samples of Qinghai Lake.As result showing, the water has low pH value, very low cation concentration and mineralization degree, and obviously migration of element Ca, Mg, Al and Fe in sediment.Few species, low biomass and lack of blue-green algae, Gastropoda, Lamellibranchia and Crustacea are most notable characteristics distinguished from general neutral and alkaline lakes.Change of element geochemistry behavior of acid aqueous medium in a lake, and its impact on organisms cause the decrease of acid sensitive species and the increase of acid tolerant species, these are the basic characteristics of Qinghai Lake and dynamic mechanism of forming acid lake environment.

Abstract:In this paper, riverwater quality prediction is integrated with water pollution control measures.Two parameters, water environmental capacity and Pollution Index are selected for pollution control measures.The objective is achieved after the development of simulation model using one-dimensional advection dispersion equation.The model algorithm and computer program is an improvement over the existing water quality models, since the model solution involves four point implicit upwind schemes for water quality prediction and pollution control measures at each grid point.Model simulation results the assessment of water environmental capacity that yield the acceptable and realistic pollutants concentration in order to maintain water quality objectives.The pollution and overall pollution index of the river is suggested for integrating number of contaminants variables into one index.Study provides the mathematical and scientific procedure forwater quality management.The new approach is helpful for the water pollution control and to study the impacts of waste effluents on the river system for strategic planning purposes.

Abstract:Kinetics and distributions of alkaline phosphatase in water, natural and filtered (<0.45μm), coupled with sediment, in constructed wetland (12.5m×9.5m)inhabited by Potamogeton crispus L., Alternanthear philoxeroides Griseb.and Spirodela polyrhiza L.respectively, were determined.The plants inactivated the enzyme, in kinetic sense, in surficial sediment and water, depending on species.The inactivation was most obvious in unfiltered water samples implying an enzymatic mechanism explaining the plant-algae interaction.In sediments covered by rooted plants, the enzymatic activity was lower in surficial layers, leading a nutrient retention and water quality amelioration, but significantly higher in the relatively deeper layers.The complexity of subsurface in wetland sediment deserves further study, which is of great theoretical and practical significance.

Abstract:From the late autumn to the early winter, several macrophytes were introduced to our newly constructed enclosures in a eutrophic lake.The purification and ecological restoration were investigated during the declining season of most macrophytes.The results show several macrophytes could be introduced to this eutrophic lake by physico-ecological engineering technique.Moreover, the newly introduced macrophytes could increase the transparency, improve water quality and remediate the eutrophic ecosystem.After three weeks, the transparency increases two-time as much as original level in the enclosure with macrophytes.Comparing with control enclosure and open water, TN concentration decreased by 43.7% and 59.4% after three weeks, 61.6% and 79.7% after six weeks, respectively;and TP concentration decreased by 50.3% and 57.0% after three weeks.

Abstract:This paper investigates preliminarily spatial distribution of soil organic matter and nitrogen in wetland soil of circular distribtuion vegetation areas in Wulanpao Wetland, Inner Mongolia, which shows that vertical distribution of nutrients in different vegetation areas are of similar tendency but their horizontal distributions are very different, and they vary along the soil moisture gradient, that is, organic matter and nitrogen content decrease with the increase of distance to waters, Polygonaceae area >Thpya orientalis area >Phragmites cmmunis area.The ratio of carbon to nitrogen(C/N)ranges from 5 to 12, and C/N values also vary with moisture gradient, but variant tendency is opposite to that of SOM and TN content in the order Phragmites cmmunis area >Thpya orientalis area >Polygonaceae area;effects of moisture, soil organic matter and total nitrogen content on C/N values ofWetland soil and grassland soil are significantly different.Moisture and plant are the key factors influencing horizontal distributons of nutrients, but pH is not the one in this region.

Abstract:This paper reports the results of comparative study on the population ecology of asian smelt(Hypomesus transpacificus nipponesis)and large icefish(Protosalanx hyalocranius)in Shuifeng Reservoir from October 1998 to November 2000, which include the behavior of feeding, growth, reprcduction and population structure.The asian smelt is an omnivorous fish which feeds mainly on zooplankton.The eggs of same spcies in spawning period were preyed upon, with a frequency of occurrence of 42.9%.It also fed on eggs of large icefish in winter with a frequency of occurrence of 2.8%.The regression equation of body weight(W)and body length(L)was W=1.176×10^-6L^3.556.The dispersed degree of body length and body weight in population structure was small.The large icefish feeds mainly on zooplankton in early life and adult fish mainly feeds on small fish and shrimp.The frequency of occurrence of asian smelt in the food was 6.9%-9.6%.The regression equation of body weight and body length was W=4.482×10^-6L^3.004.The dispersed degree of body length and body weight was large which showing difference of individual growth.

Abstract:The seasonal succession and diversity of zooplankton in saline-alkaline ponds from 5th April, 1997 to 1st September, 1998, in Zhaodian Fish Farm, Gaoqing County, Shandong Province, were examined.389 zooplankton samples were collected.Rotifer was dominant in summer and autumn when water temperature was higher.Copepod was predominant in many fish-culture ponds and all control ponds in spring and in late autumn and early winter.The biomass of protozoa in fish-culture ponds was relative higher than control ponds.The zooplankton biomass, in general, peaked in spring, summer and early autumn.The seasonal dynamic pattern of diversity index of zooplankton is not the same as that of biomass of zooplankton.The diversity was lower in winter, increased in spring, reached the highest in summer, and decreased in autumn.The diversity index of zooplankton was low during the peak period of biomass of zooplankton, and increased with the decrease of biomass of zooplankton.The biomass of zooplankton in control ponds and new ponds was greater than that of other fish-culture ponds.

Abstract:With the rapid social economic development, the ecological environment in Wuxi city has been worsened during the past 20 years, the pollution of water resource is especially serious and the water quality was decreased by one class in every 5 to 10 years.This paper studied the main factors and reasons of the effects of the social economic development on the water environment, especially Taihu Lake.Some measures to improve the water environment are suggested, i.e., the adjustment of industrial structures, improvement of recycle utilition rate of water resources, administration of sewage in the market economy and environment education to the people and so on.

Abstract:Based on the analysis of the eco-tour resources at the Wuzhong District in Suzhou city, the authors put forward a new idea for constructing eco-tour belt around Taihu Lake and determine the policy in developing eco-tour in view of two respects:spatial distribution and the conformity of eco-tour resources, market development.The authors also propose a suggestion to integrate the Wu culture into the nature landscape in main tour areas.There are some important measures to change traditional tour into eco-tour: optimizing tourism and the structure of products, constructing the eco-tour service system around Taihu Lake, we must take severe measures to manage tour environment.

Abstract:The role and problem of macrophyte in artificial wetland for wastewater treatment are summarized and some research interests are proposed in this paper.Macrophyte plays three important roles in artificial wetland.1)Uptake the nutrients, adsorb and accumulate heavy metal and poisonous substances from wastewater.2) Transfer oxygen to rhizophere for the growth, reproduction and decompositions of microorganisms.3)Enhance and stabilize the hydraulic transportation of media.However, die-back of macrophyte, grown weed and shallow extension of root in the wetland, which affect the growth and purification efficiency of plants in wetland, are porblems for artificial wetland management.To strengthen and enhance the roles of macrophyte and the wastewater purification function of artificial wetland, the physiological ecology of macrophyte such as gas transportation and exchange, photosynthesis, stressed physiology and allelopathy of macrophyte should be studied further to select optimum macrophyte species and suitable artificial habitat should be established in the artificial wetland.

Abstract:Energy densities of 72 species of macroinvertebrates in China were measured with microcalorimeter, among which 69 species were first calculated.The energy densities of oligochaetes were 22.99-25.08 kJ/g (dry weight), those of molluscs were16.72-22.99kJ/g (dry weight), and those of insects and their larvae varied markedly, with the range from 10.45 to 25.08kJ/g (dry weight).The density of a species differs to some extent with the changes of season, locality and age.