A sequential extraction method for the fractionation of phosphorus （P） in lake sediments was used to analyze phos- phorus fractions of sediments taken from three large, shallow. eutrophic freshwater lakes of China-T...A sequential extraction method for the fractionation of phosphorus （P） in lake sediments was used to analyze phos- phorus fractions of sediments taken from three large, shallow. eutrophic freshwater lakes of China-Talhu Lake. Chaohu Lake, and Long.an Lake. All three lakes are located in the lower reaches of the Changjiang River （Yangtze River）. In Taihu Lake and Chaohu Lake, algae blooms occurred every year, while Longgan Lake was a macrophyte-dominated lake. Results showed that exchangeable phosphorus fractions were much higher in the eutrophic lake sediments than in the macrophyte-flourishing lake sediment. Also, the ratio of Fe：P in the sediments of the algae-predomlnant lakes was generally much lower than that in the macrophyte-predominant lakes. Thus, the geochemical fractions of phosphorus in sediments had a closer relationship with the type of aquatic vegetation.展开更多
Starvation metabolism is one of the important parts of respiration for normal activities of chironomids. During April 1996 to March 1997, the relationships of starvation metabolism and temperature, body weight of two ...Starvation metabolism is one of the important parts of respiration for normal activities of chironomids. During April 1996 to March 1997, the relationships of starvation metabolism and temperature, body weight of two common chironomids in Biandantang Lake were carefully investigated. The results showed relationship between starvation metabolism （R, mgO2/ind.d） and body weight （Ww, mg wet wt） was： Chironomus plumosus, 1gR=-2.573＋1.0211gWw （5℃）, 1gR=-2.710＋1.3541gWw （10℃）, 1gR= -1.824＋0.8231gWw （15℃）, 1gR=-1.364＋0.4421gWw （20℃）, 1gR=-2.763＋1.5171gWw （25℃）; and Tokunagayusurika akamusi, 1gR=-2.390＋0.7521gWw （5℃）, 1gR=-1.978＋0.7101gWw （10℃）, 1gR=-1.676＋ 0.6481gWw （15℃）, 1gR=-1.517＋0.6501gWw （20℃）, 1gR=-2.434＋1.2901gWw （25℃）. Relationship of starvation metabolism and temperature （T, ℃） was： C. plumosus, R = -0.051 ＋ 0.021T- 0.0006T^2 ; akamusi, R= -0.051 ＋ 0.021T- 0.0006T^2. The complex relationship of the three parameters was： C. plumosus, R=0.0098Ww^0.3882e^0.1068T; T. akamusi, R=0.0012Ww^1.1936e^0.0711r. With the above regressions, the estimated annual starvation metabolisms of the two chironomid species in Biandantang Lake were： C. plumosus, 24.2791 kJ/m^2.a; T. akamusi, 8.7864 kJ/m^2.a, respectively. This provides a firm foundation for the comparative study of bioenergetics of the chironomids.展开更多
Based on reviewing the problems in limnology and watershed sciences in meeting the national demands and the development of theories and methodology, this paper proposed some challeng-ing topics to the sciences, coveri...Based on reviewing the problems in limnology and watershed sciences in meeting the national demands and the development of theories and methodology, this paper proposed some challeng-ing topics to the sciences, covering the process of lake evolution and the quantitative analysis of hu-man impacts, in-lake nutrient cycling an biogeo-chemical process, the process and mechanisms of material flow in lake-watershed system, digital watershed and the modeling of the surface pro-cess of lake-watershed, and ecosystem health and scientific management of lake- watershed.展开更多
The paper presents the analysis of tendencies in water level changes in 32 lakes in Poland during 1976–2010.Series of monthly,seasonal,and annual precipitation and air temperature for 9 meteorological stations were a...The paper presents the analysis of tendencies in water level changes in 32 lakes in Poland during 1976–2010.Series of monthly,seasonal,and annual precipitation and air temperature for 9 meteorological stations were also studied.The trend analysis for all of the studied series of water levels in lakes showed high spatial and temporal variability.Series of annual water levels in the case of 6 lakes showed statistically significant increasing tendencies,and in 7 lakes,significant decreasing trends.Series of annual amplitudes in the majority of lakes(22) showed a decreasing trend,but they were statistically significant only in three cases.The tendencies for air temperature fluctuations are more statistically significant than precipitation.The key role in determining water level changes is played by local factors,particularly including human economic activity,obscuring the effect of natural factors on water level changes.The paper describes cases of changes in water levels in lakes under anthropopressure related to among others: agricultural irrigations,hydropower infrastructure,water transfers,navigation,or mining.展开更多
基金Project supported by the Knowledge Innovation Program of the Chinese Academy of Sciences (No.KZCX1-SW-12)
文摘A sequential extraction method for the fractionation of phosphorus （P） in lake sediments was used to analyze phos- phorus fractions of sediments taken from three large, shallow. eutrophic freshwater lakes of China-Talhu Lake. Chaohu Lake, and Long.an Lake. All three lakes are located in the lower reaches of the Changjiang River （Yangtze River）. In Taihu Lake and Chaohu Lake, algae blooms occurred every year, while Longgan Lake was a macrophyte-dominated lake. Results showed that exchangeable phosphorus fractions were much higher in the eutrophic lake sediments than in the macrophyte-flourishing lake sediment. Also, the ratio of Fe：P in the sediments of the algae-predomlnant lakes was generally much lower than that in the macrophyte-predominant lakes. Thus, the geochemical fractions of phosphorus in sediments had a closer relationship with the type of aquatic vegetation.
基金Supported by NSFC (No. 30270278, 39430101 and 3960019)
文摘Starvation metabolism is one of the important parts of respiration for normal activities of chironomids. During April 1996 to March 1997, the relationships of starvation metabolism and temperature, body weight of two common chironomids in Biandantang Lake were carefully investigated. The results showed relationship between starvation metabolism （R, mgO2/ind.d） and body weight （Ww, mg wet wt） was： Chironomus plumosus, 1gR=-2.573＋1.0211gWw （5℃）, 1gR=-2.710＋1.3541gWw （10℃）, 1gR= -1.824＋0.8231gWw （15℃）, 1gR=-1.364＋0.4421gWw （20℃）, 1gR=-2.763＋1.5171gWw （25℃）; and Tokunagayusurika akamusi, 1gR=-2.390＋0.7521gWw （5℃）, 1gR=-1.978＋0.7101gWw （10℃）, 1gR=-1.676＋ 0.6481gWw （15℃）, 1gR=-1.517＋0.6501gWw （20℃）, 1gR=-2.434＋1.2901gWw （25℃）. Relationship of starvation metabolism and temperature （T, ℃） was： C. plumosus, R = -0.051 ＋ 0.021T- 0.0006T^2 ; akamusi, R= -0.051 ＋ 0.021T- 0.0006T^2. The complex relationship of the three parameters was： C. plumosus, R=0.0098Ww^0.3882e^0.1068T; T. akamusi, R=0.0012Ww^1.1936e^0.0711r. With the above regressions, the estimated annual starvation metabolisms of the two chironomid species in Biandantang Lake were： C. plumosus, 24.2791 kJ/m^2.a; T. akamusi, 8.7864 kJ/m^2.a, respectively. This provides a firm foundation for the comparative study of bioenergetics of the chironomids.
文摘Based on reviewing the problems in limnology and watershed sciences in meeting the national demands and the development of theories and methodology, this paper proposed some challeng-ing topics to the sciences, covering the process of lake evolution and the quantitative analysis of hu-man impacts, in-lake nutrient cycling an biogeo-chemical process, the process and mechanisms of material flow in lake-watershed system, digital watershed and the modeling of the surface pro-cess of lake-watershed, and ecosystem health and scientific management of lake- watershed.
文摘The paper presents the analysis of tendencies in water level changes in 32 lakes in Poland during 1976–2010.Series of monthly,seasonal,and annual precipitation and air temperature for 9 meteorological stations were also studied.The trend analysis for all of the studied series of water levels in lakes showed high spatial and temporal variability.Series of annual water levels in the case of 6 lakes showed statistically significant increasing tendencies,and in 7 lakes,significant decreasing trends.Series of annual amplitudes in the majority of lakes(22) showed a decreasing trend,but they were statistically significant only in three cases.The tendencies for air temperature fluctuations are more statistically significant than precipitation.The key role in determining water level changes is played by local factors,particularly including human economic activity,obscuring the effect of natural factors on water level changes.The paper describes cases of changes in water levels in lakes under anthropopressure related to among others: agricultural irrigations,hydropower infrastructure,water transfers,navigation,or mining.
