This study was designed to find out an optimised planting system of reducing non-point (source) pollution by analyzing the reasons and the factors of influence non-point pollution in farmland of Erhai Lake basin. Th...This study was designed to find out an optimised planting system of reducing non-point (source) pollution by analyzing the reasons and the factors of influence non-point pollution in farmland of Erhai Lake basin. The results showed that incomes, residual nitrogen in soil, and the loss of nitrogen in surface water in rice-garlic system were higher than those in rice-fava bean system. There were positive correlations between the nitrogen loss of farmland, nitrogen inputs, residual nitrogen in soil, and incomes of farmland. Economic benefits and environment benefits are both appropriate, if the area of rice-garlic system would be reduced to 53% and the area of rice-fava bean system increased to 36% of total cropping area in the investigated watershed. Adjustment of planting structure and introduction of reasonable rotation systems is considered an effective measure of controlling agricultural non-point pollution in watersheds of Erhai Lake.展开更多
THE Bai people are China’s 15th largest ethnic minority.They live mainly in Yunnan Province,specifically in Dali Bai Autonomous Prefecture,and some in Guizhou and Hunan provinces.Dali is where the Bai people’s ethni...THE Bai people are China’s 15th largest ethnic minority.They live mainly in Yunnan Province,specifically in Dali Bai Autonomous Prefecture,and some in Guizhou and Hunan provinces.Dali is where the Bai people’s ethnic roots are.From the 23rd to 25th day of the fourth lunar month every year,Bai people in Dali pray for展开更多
The seasonal dynamics of a crustacean zooplankton community in Erhai Lake was investigated from May 2010 to April 2011. In total, 11 species were recorded, including six(6 genera) cladoceran and five(5 genera) copepod...The seasonal dynamics of a crustacean zooplankton community in Erhai Lake was investigated from May 2010 to April 2011. In total, 11 species were recorded, including six(6 genera) cladoceran and five(5 genera) copepod species. The crustacean zooplankton densities ranged from 24.3 to 155.4 ind./L. In winter and spring, the large-bodied cladoceran Daphnia galeata dominated the crustacean plankton community. In summer and autumn, when the colonial or filamentous algae dominated the phytoplankton communities, the small-bodied species(e.g. B osmina fatalis, Ceriodaphnia quadrangular, and Mesocyclops leuckarti) replaced the large-bodied ones. One-way ANOVA and redundancy analysis revealed that community structure was dependent upon total nitrogen, total phosphorus, water temperature, transparency, and the biomass of small algae. The variation in both phytoplankton structure and environmental variables were important factors in the seasonal succession of crustacean zooplankton structure in Erhai Lake.展开更多
<Abstract>Erhai Lake is the second largest freshwater lake on the Yunnan Plateau, Southwest China. In recent decades, a number of exotic fish species have been introduced into the lake and the fish community has...<Abstract>Erhai Lake is the second largest freshwater lake on the Yunnan Plateau, Southwest China. In recent decades, a number of exotic fish species have been introduced into the lake and the fish community has changed considerably. We evaluated the status of the fish community based on surveys with multimesh gillnet, trap net, and benthic fyke-net between May 2009 and April 2012. In addition,we evaluated the change in the community using historical data (1952-2010)describing the fish community and fishery harvest. The current fish community is dominated by small-sized fishes, including Pseudorasbora parva, Rhinogobius giurinus, Micropercops swinhonis, Hemiculter leucisculus, and Rhinogobius cliffordpopei. These accounted for 87.7% of the 22 546 total specimens collected.0mnivorous and carnivorous species dominated the community. A canonical correspondence analysis (CCA) plot revealed that the distribution of fishes in the lake is influenced by aquatic plants,water temperature, pH, and season. The abundance of indigenous species hasdeclined sharply, and a majority of endemic species have been extirpated from the lake (adecrease from seven to two species). In contrast, the number of exotic species has increased since the 1960s to a total of 22 at present. The fishery harvest decreased initially following the 1960s, but has since increased due to the introduction of non-native fish and stocking of native fish. The fishery harvest was significantly correlated with total nitrogen, not total phosphorus,during the past20 years. Based on our results,wediscuss recommendations for the restoration and conservation of the fish resources in Erhai Lake.展开更多
Ths study on the physico-geograpical environment of Erhai Lake focused on the suspended matter and recent deposition rates, 14 C, 210 Pb and 137 Cs methods were used to determine the ageand sedimentation rate, which w...Ths study on the physico-geograpical environment of Erhai Lake focused on the suspended matter and recent deposition rates, 14 C, 210 Pb and 137 Cs methods were used to determine the ageand sedimentation rate, which was found to be 0.5 t0 2.0 mm/a, average of 0.9 mm/a. The authors calculated the budget of some elements by studying the deposition, and fuUnd that about 30% of nitrogen,and most of the phosphorous, were transported into the lake by the ediments.展开更多
Objective:To investigate the ectoparasite communities on Tupaia belangeri (T. belangeri) in the surrounding areas of Erhai Lake and their potential importance in medical and veterinary science. Methods: Different loca...Objective:To investigate the ectoparasite communities on Tupaia belangeri (T. belangeri) in the surrounding areas of Erhai Lake and their potential importance in medical and veterinary science. Methods: Different locations in surrounding areas of Erhai Lake in Yunnan were selected as the investigation spots. T. belangeri were randomly captured with baited mouse cages and then brought to the laboratory for identification according to their body shape, size and color, and measurements such as the lengths of their body, ear and hind feet. Ectoparasites on them were collected and identified to determine the species under microscope after specimens were mounted on slides, with the clearing and drying process completed. The constituent ratio (C), prevalence (P) and average ectoparasite abundance (A) were used to test the prevalence and density of ectoparasites; Non-parametric Mann-Whitney U-tests were used to test the differences in the abundance and richness of ectoparasites between female and male hosts; Spearman correlation analysis was used to analyze the relationship between ectoparasites and the body parameters of hosts. Results: There was very high species diversity of ectoparasites found on T. belangeri and some species of ectoparasites were reported associated with human diseases. A high proportion (88%) of 107 T. belangeri was found to be infested with ectoparasites. A total of 75 species of ectoparasites on them were collected, including 58 species of chigger mite, 12 species of gamasid mite, 4 species of flea and 1 species of sucking louse. Within this ectoparasite complex, 13 species were previously reported to be vectors of human disease agents. Non-parametric Mann-Whitney U-tests showed significant differences between male and female T. belangeri in terms of the abundance and richness of total ectoparasites. However, the species richness and abundance of chigger mites, sucking lice, fleas or gamasid mites presented no significant differences between male and female hosts. Spearman correlation analysis showed that none of correlations were observed between host body parameters with abundance and richness of total ectoparasites, chigger mites, suckinglice, fleas or gamatid mites. Conclusion: The results suggest that there is very high species diversity of ectoparasites on T. belangeri, consisting mainly of communities of sucking lice, fleas, chiggers and gamasid mites.展开更多
The study first systematically assessed the ecosystem health status of the plateau freshwater lake of Erhai Lake in Yunnan Province of China,using the revised Freshwater Health Indicator methodology,which comprised th...The study first systematically assessed the ecosystem health status of the plateau freshwater lake of Erhai Lake in Yunnan Province of China,using the revised Freshwater Health Indicator methodology,which comprised three components,i.e.,“Ecosystem Vitality,”“Ecosystem Services,”and“Governance and Stakeholders.”To better reflect the real health status of the basin,the cask short board effect was considered during aggregation of the indicators.In addition,analysis of the coupling coordination relationship among the three components was conducted to study the mutual influences among them as well as the comprehensive development level of the studied area.Basically,the ecosystem of the Erhai Lake basin remained healthy during the studied period according to the research due to specific measures and actions taken to manage the environmental problems caused by a former local economic development and urbanization process.However,there were still aspects to improve for more sustainable ecosystem management and utilization in the basin.The“short boards”of the Erhai Lake basin show room for improvement in local freshwater ecosystem management and underline governance problems that need to be addressed.Suggestions are provided for the local stakeholders consequently for the more sustainable development of the studied basin.展开更多
Measurement of turbulence fluxes were performed over the Erhai Lake using eddy covariance(EC) method.Basic physical parameters in the lake-air interaction processes,such as surface albedo of the lake,aerodynamic rough...Measurement of turbulence fluxes were performed over the Erhai Lake using eddy covariance(EC) method.Basic physical parameters in the lake-air interaction processes,such as surface albedo of the lake,aerodynamic roughness length,bulk transfer coefficients,etc.,were investigated using the EC data in 2012.The characteristics of turbulence fluxes over the lake including momentum flux,sensible heat flux,latent heat flux,and CO2 flux,and their controlling factors were analyzed.The total annual evaporation of the lake was also estimated based on the artificial neural network(ANN) gap-filling technique.Results showed that the total annual evaporation in 2012 was 1165 ± 15 mm,which was larger than the annual precipitation(818 mm).Local circulation between the lake and the surrounding land was found to be significant throughout the year due to the land-lake breeze or the mountain-valley breeze in this area.The prevailing winds of southeasterly and northwesterly were observed throughout the year.The sensible heat flux over this plateau lake usually had a few tens of W m-2,and generally became negative in the afternoon,indicating that heat was transferred from the lake to the atmosphere.The sensible heat flux was governed by the lake-air temperature difference and had its maximum in the early morning.The diurnal variation of the latent heat flux was controlled by vapor pressure deficit with a peak in the afternoon.The latent heat flux was dominant in the partition of available energy in daytime over this lake.The lake acted as a weak CO2 source to the atmosphere except for the midday of summer.Seasonal variations of surface albedo over the lake were related to the solar elevation angle and opacity of the water.Furthermore,compared with the observation data,the surface albedo estimated by CLM4-LISSS model was underestimated in winter and overestimated in summer.展开更多
IN recent years, much progress has been made in the research of the temporal and spatial changes of East Asian monsoon. To research the environmental evolution and monsoon variations in Holocene in the region of South...IN recent years, much progress has been made in the research of the temporal and spatial changes of East Asian monsoon. To research the environmental evolution and monsoon variations in Holocene in the region of Southwest China, a 310-cm continuous lake sediments core in Erhai Lake, Yunnan Province was sampled with Livingston sampler on July 6, 1996. The lake sediments were separated at 2-cm intervals and the core samples were analyzed with chronology, stable isotope ratios of organic carbon and diatoms determination. Three <sup>14</sup>C ages are (4 473±40)a B.P. (98—102 cm), (5 825±85) a B. P. (144—148 cm) and (7 754±45) a B.P. (198—202 cm). By <sup>137</sup>Cs dating, the sedimentation rate is about 0.3 mm/a and this result is close to the <sup>14</sup>C dating results. The average sedimentation rates展开更多
THE formation and uplift of the Himalayas and the Tibetan Plateau may have been responsible for the past150 Ma global environmental changes, resulting in the development of a three-tiered landform in southernChina. Th...THE formation and uplift of the Himalayas and the Tibetan Plateau may have been responsible for the past150 Ma global environmental changes, resulting in the development of a three-tiered landform in southernChina. The Yunnan-Guizhou Plateau, as the middle tier in eastern slope of the Himalayas, has beencomplex environmental unit with great altitude gradients and plateau landform characters. Both monsoonsfrom the Pacific and the Indian resulting in apparent environmental changes on variable time scales influence it. Environmental geochemical effect of low latitude-high altitude could be yielded, and well recorded in the geological bodies in this region. To build and verify a quantitative model of environmental evolution it is necessary to obtain high-resolution data of elemental cycles and mass equilibrium.展开更多
A closed or semi\|closed plateau lake, whose sediment records can provide us with plenty of fine and high resolution information, is a sensitive indicator of climatic and environmental changes. During the reconstructi...A closed or semi\|closed plateau lake, whose sediment records can provide us with plenty of fine and high resolution information, is a sensitive indicator of climatic and environmental changes. During the reconstruction of various short\|time\|scale climatic and environmental changes, the geochemical records in plateau\|lake sediments are superior to other natural files. Based on fine dissection of the vertical profile of sediment particle sizes, this paper reveals the quasi\|periodical changes of sediment particle sizes, which indicates the quasi\|periodical fluctuations of the regional climate. A synthetic analysis of multiple indexes shows that sediment particle size is a more sensitive and more effective index of climatic and environmental changes than other geochemical indexes. High content of >20 μm sediment particles and low content of 2-10 μm sediment particles indicate a warm\|dry climate and conversely a cold\|humid climate, and their ratio can be used as an effective index of climatic changes. The basic climate succession in the region of Lake Erhai is characterized as being alternatively warm\|dry and cold\|humid and it has been developing into a warm\|dry climate as a whole. There exist at least 2 time\|scale quasi\|periodical fluctuations of the regional climate in Lake Erhai. At present, the region of Lake Erhai is at the end of the warm\|dry period and at the beginning of a cold\|humid period, so the temperature will go down and the water level will rise.展开更多
Erhai Lake is a large lake with important climatic significance in Yunnan Province, southwest China. The multi-proxy sedimentary records from Erhai Lake indicate the 9 stages of climatic changes with the alternation o...Erhai Lake is a large lake with important climatic significance in Yunnan Province, southwest China. The multi-proxy sedimentary records from Erhai Lake indicate the 9 stages of climatic changes with the alternation of warm-dry and cool-wet during the past 8000 a. The variations of Asian monsoon systems were the main cause for the climatic changes in southwest China. The warm-dry period was coincident with the intensification of India monsoon and Northwest Pacific Sub-tropical High Pressure, and the cool-wet corresponding to weak of India monsoon and its main rain belt moving back to southwest China.展开更多
IN the past half a century, the global paleoclimate has been successfully reconstructed by natural recordssuch as ice core, loess and deep-sea sediments. However, these works mostly focused on long-timescale climatic ...IN the past half a century, the global paleoclimate has been successfully reconstructed by natural recordssuch as ice core, loess and deep-sea sediments. However, these works mostly focused on long-timescale climatic changes. Along with the appearance of modern environmental problems including globalwarming, people are increasingly concerned about short-term climatic variations (annual to century scale)within the historical period. Therefore, it is an urgent and significant task for scientists to obtain continuous and high resolution natural records so as to reconstruct recent climatic changes truly and predict theclimate in the near future. As a main lodging of surface substances, the plateau-lake sediment continuously records the information of regional climate and environment with annual to decade resolution. Undoubtedly it is one展开更多
基金funded by the National Water Special Program of China during 11th Five-Year Plan period(2008ZX07105-002)
文摘This study was designed to find out an optimised planting system of reducing non-point (source) pollution by analyzing the reasons and the factors of influence non-point pollution in farmland of Erhai Lake basin. The results showed that incomes, residual nitrogen in soil, and the loss of nitrogen in surface water in rice-garlic system were higher than those in rice-fava bean system. There were positive correlations between the nitrogen loss of farmland, nitrogen inputs, residual nitrogen in soil, and incomes of farmland. Economic benefits and environment benefits are both appropriate, if the area of rice-garlic system would be reduced to 53% and the area of rice-fava bean system increased to 36% of total cropping area in the investigated watershed. Adjustment of planting structure and introduction of reasonable rotation systems is considered an effective measure of controlling agricultural non-point pollution in watersheds of Erhai Lake.
文摘THE Bai people are China’s 15th largest ethnic minority.They live mainly in Yunnan Province,specifically in Dali Bai Autonomous Prefecture,and some in Guizhou and Hunan provinces.Dali is where the Bai people’s ethnic roots are.From the 23rd to 25th day of the fourth lunar month every year,Bai people in Dali pray for
基金Supported by the National Natural Science Foundation of China(No.31070387)the National Water Pollution Control and Management Technology Major Projects of China(No.2008ZC07105-005)
文摘The seasonal dynamics of a crustacean zooplankton community in Erhai Lake was investigated from May 2010 to April 2011. In total, 11 species were recorded, including six(6 genera) cladoceran and five(5 genera) copepod species. The crustacean zooplankton densities ranged from 24.3 to 155.4 ind./L. In winter and spring, the large-bodied cladoceran Daphnia galeata dominated the crustacean plankton community. In summer and autumn, when the colonial or filamentous algae dominated the phytoplankton communities, the small-bodied species(e.g. B osmina fatalis, Ceriodaphnia quadrangular, and Mesocyclops leuckarti) replaced the large-bodied ones. One-way ANOVA and redundancy analysis revealed that community structure was dependent upon total nitrogen, total phosphorus, water temperature, transparency, and the biomass of small algae. The variation in both phytoplankton structure and environmental variables were important factors in the seasonal succession of crustacean zooplankton structure in Erhai Lake.
基金Supported by the National Special Research Fund for Non-Profit Sector(Agriculture)(No.200903048-04)the Major Science and Technology Program for Water Pollution Control and Treatment of China(No.2012ZX07105-004)the State Key Program of National Natural Science Foundation of China(No.30830025)
文摘<Abstract>Erhai Lake is the second largest freshwater lake on the Yunnan Plateau, Southwest China. In recent decades, a number of exotic fish species have been introduced into the lake and the fish community has changed considerably. We evaluated the status of the fish community based on surveys with multimesh gillnet, trap net, and benthic fyke-net between May 2009 and April 2012. In addition,we evaluated the change in the community using historical data (1952-2010)describing the fish community and fishery harvest. The current fish community is dominated by small-sized fishes, including Pseudorasbora parva, Rhinogobius giurinus, Micropercops swinhonis, Hemiculter leucisculus, and Rhinogobius cliffordpopei. These accounted for 87.7% of the 22 546 total specimens collected.0mnivorous and carnivorous species dominated the community. A canonical correspondence analysis (CCA) plot revealed that the distribution of fishes in the lake is influenced by aquatic plants,water temperature, pH, and season. The abundance of indigenous species hasdeclined sharply, and a majority of endemic species have been extirpated from the lake (adecrease from seven to two species). In contrast, the number of exotic species has increased since the 1960s to a total of 22 at present. The fishery harvest decreased initially following the 1960s, but has since increased due to the introduction of non-native fish and stocking of native fish. The fishery harvest was significantly correlated with total nitrogen, not total phosphorus,during the past20 years. Based on our results,wediscuss recommendations for the restoration and conservation of the fish resources in Erhai Lake.
文摘Ths study on the physico-geograpical environment of Erhai Lake focused on the suspended matter and recent deposition rates, 14 C, 210 Pb and 137 Cs methods were used to determine the ageand sedimentation rate, which was found to be 0.5 t0 2.0 mm/a, average of 0.9 mm/a. The authors calculated the budget of some elements by studying the deposition, and fuUnd that about 30% of nitrogen,and most of the phosphorous, were transported into the lake by the ediments.
基金Supported by the Natural Science Foundation of China (30460125)
文摘Objective:To investigate the ectoparasite communities on Tupaia belangeri (T. belangeri) in the surrounding areas of Erhai Lake and their potential importance in medical and veterinary science. Methods: Different locations in surrounding areas of Erhai Lake in Yunnan were selected as the investigation spots. T. belangeri were randomly captured with baited mouse cages and then brought to the laboratory for identification according to their body shape, size and color, and measurements such as the lengths of their body, ear and hind feet. Ectoparasites on them were collected and identified to determine the species under microscope after specimens were mounted on slides, with the clearing and drying process completed. The constituent ratio (C), prevalence (P) and average ectoparasite abundance (A) were used to test the prevalence and density of ectoparasites; Non-parametric Mann-Whitney U-tests were used to test the differences in the abundance and richness of ectoparasites between female and male hosts; Spearman correlation analysis was used to analyze the relationship between ectoparasites and the body parameters of hosts. Results: There was very high species diversity of ectoparasites found on T. belangeri and some species of ectoparasites were reported associated with human diseases. A high proportion (88%) of 107 T. belangeri was found to be infested with ectoparasites. A total of 75 species of ectoparasites on them were collected, including 58 species of chigger mite, 12 species of gamasid mite, 4 species of flea and 1 species of sucking louse. Within this ectoparasite complex, 13 species were previously reported to be vectors of human disease agents. Non-parametric Mann-Whitney U-tests showed significant differences between male and female T. belangeri in terms of the abundance and richness of total ectoparasites. However, the species richness and abundance of chigger mites, sucking lice, fleas or gamasid mites presented no significant differences between male and female hosts. Spearman correlation analysis showed that none of correlations were observed between host body parameters with abundance and richness of total ectoparasites, chigger mites, suckinglice, fleas or gamatid mites. Conclusion: The results suggest that there is very high species diversity of ectoparasites on T. belangeri, consisting mainly of communities of sucking lice, fleas, chiggers and gamasid mites.
基金The study was supported by the National Natural Science Foundation of China(51779002).
文摘The study first systematically assessed the ecosystem health status of the plateau freshwater lake of Erhai Lake in Yunnan Province of China,using the revised Freshwater Health Indicator methodology,which comprised three components,i.e.,“Ecosystem Vitality,”“Ecosystem Services,”and“Governance and Stakeholders.”To better reflect the real health status of the basin,the cask short board effect was considered during aggregation of the indicators.In addition,analysis of the coupling coordination relationship among the three components was conducted to study the mutual influences among them as well as the comprehensive development level of the studied area.Basically,the ecosystem of the Erhai Lake basin remained healthy during the studied period according to the research due to specific measures and actions taken to manage the environmental problems caused by a former local economic development and urbanization process.However,there were still aspects to improve for more sustainable ecosystem management and utilization in the basin.The“short boards”of the Erhai Lake basin show room for improvement in local freshwater ecosystem management and underline governance problems that need to be addressed.Suggestions are provided for the local stakeholders consequently for the more sustainable development of the studied basin.
基金supported by the National Natural Science Foundation of China(Grant Nos.41030106,41021004)the National Basic Research Program of China(Grant No.2010CB951801)
文摘Measurement of turbulence fluxes were performed over the Erhai Lake using eddy covariance(EC) method.Basic physical parameters in the lake-air interaction processes,such as surface albedo of the lake,aerodynamic roughness length,bulk transfer coefficients,etc.,were investigated using the EC data in 2012.The characteristics of turbulence fluxes over the lake including momentum flux,sensible heat flux,latent heat flux,and CO2 flux,and their controlling factors were analyzed.The total annual evaporation of the lake was also estimated based on the artificial neural network(ANN) gap-filling technique.Results showed that the total annual evaporation in 2012 was 1165 ± 15 mm,which was larger than the annual precipitation(818 mm).Local circulation between the lake and the surrounding land was found to be significant throughout the year due to the land-lake breeze or the mountain-valley breeze in this area.The prevailing winds of southeasterly and northwesterly were observed throughout the year.The sensible heat flux over this plateau lake usually had a few tens of W m-2,and generally became negative in the afternoon,indicating that heat was transferred from the lake to the atmosphere.The sensible heat flux was governed by the lake-air temperature difference and had its maximum in the early morning.The diurnal variation of the latent heat flux was controlled by vapor pressure deficit with a peak in the afternoon.The latent heat flux was dominant in the partition of available energy in daytime over this lake.The lake acted as a weak CO2 source to the atmosphere except for the midday of summer.Seasonal variations of surface albedo over the lake were related to the solar elevation angle and opacity of the water.Furthermore,compared with the observation data,the surface albedo estimated by CLM4-LISSS model was underestimated in winter and overestimated in summer.
文摘IN recent years, much progress has been made in the research of the temporal and spatial changes of East Asian monsoon. To research the environmental evolution and monsoon variations in Holocene in the region of Southwest China, a 310-cm continuous lake sediments core in Erhai Lake, Yunnan Province was sampled with Livingston sampler on July 6, 1996. The lake sediments were separated at 2-cm intervals and the core samples were analyzed with chronology, stable isotope ratios of organic carbon and diatoms determination. Three <sup>14</sup>C ages are (4 473±40)a B.P. (98—102 cm), (5 825±85) a B. P. (144—148 cm) and (7 754±45) a B.P. (198—202 cm). By <sup>137</sup>Cs dating, the sedimentation rate is about 0.3 mm/a and this result is close to the <sup>14</sup>C dating results. The average sedimentation rates
文摘THE formation and uplift of the Himalayas and the Tibetan Plateau may have been responsible for the past150 Ma global environmental changes, resulting in the development of a three-tiered landform in southernChina. The Yunnan-Guizhou Plateau, as the middle tier in eastern slope of the Himalayas, has beencomplex environmental unit with great altitude gradients and plateau landform characters. Both monsoonsfrom the Pacific and the Indian resulting in apparent environmental changes on variable time scales influence it. Environmental geochemical effect of low latitude-high altitude could be yielded, and well recorded in the geological bodies in this region. To build and verify a quantitative model of environmental evolution it is necessary to obtain high-resolution data of elemental cycles and mass equilibrium.
文摘A closed or semi\|closed plateau lake, whose sediment records can provide us with plenty of fine and high resolution information, is a sensitive indicator of climatic and environmental changes. During the reconstruction of various short\|time\|scale climatic and environmental changes, the geochemical records in plateau\|lake sediments are superior to other natural files. Based on fine dissection of the vertical profile of sediment particle sizes, this paper reveals the quasi\|periodical changes of sediment particle sizes, which indicates the quasi\|periodical fluctuations of the regional climate. A synthetic analysis of multiple indexes shows that sediment particle size is a more sensitive and more effective index of climatic and environmental changes than other geochemical indexes. High content of >20 μm sediment particles and low content of 2-10 μm sediment particles indicate a warm\|dry climate and conversely a cold\|humid climate, and their ratio can be used as an effective index of climatic changes. The basic climate succession in the region of Lake Erhai is characterized as being alternatively warm\|dry and cold\|humid and it has been developing into a warm\|dry climate as a whole. There exist at least 2 time\|scale quasi\|periodical fluctuations of the regional climate in Lake Erhai. At present, the region of Lake Erhai is at the end of the warm\|dry period and at the beginning of a cold\|humid period, so the temperature will go down and the water level will rise.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 49672132) the Western Project of Chinese Academy of Sciences (Grant No, KZCX 1-10-01) as well as the Hwaying Education and Culture Foundation.
文摘Erhai Lake is a large lake with important climatic significance in Yunnan Province, southwest China. The multi-proxy sedimentary records from Erhai Lake indicate the 9 stages of climatic changes with the alternation of warm-dry and cool-wet during the past 8000 a. The variations of Asian monsoon systems were the main cause for the climatic changes in southwest China. The warm-dry period was coincident with the intensification of India monsoon and Northwest Pacific Sub-tropical High Pressure, and the cool-wet corresponding to weak of India monsoon and its main rain belt moving back to southwest China.
文摘IN the past half a century, the global paleoclimate has been successfully reconstructed by natural recordssuch as ice core, loess and deep-sea sediments. However, these works mostly focused on long-timescale climatic changes. Along with the appearance of modern environmental problems including globalwarming, people are increasingly concerned about short-term climatic variations (annual to century scale)within the historical period. Therefore, it is an urgent and significant task for scientists to obtain continuous and high resolution natural records so as to reconstruct recent climatic changes truly and predict theclimate in the near future. As a main lodging of surface substances, the plateau-lake sediment continuously records the information of regional climate and environment with annual to decade resolution. Undoubtedly it is one