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Palaeoclihlatic Indicators of China's Quaternary Saline Lake Sediments and Hydrochemistry 被引量:17
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作者 ZHENG Mianping, ZHAO Yuanyi and LIU JunyingResearch & Development Center of Saline Lake and Epithermal Deposits,Chinese Academy of Geological Sciences, Beijing 100037 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2000年第2期259-265,共7页
In this paper the authors classify saline lake sediments into the cold, warm and eurythermal phases, reveal the consistency between the zoning of hydrochemical types of modern saline lake water and climatic zoning and... In this paper the authors classify saline lake sediments into the cold, warm and eurythermal phases, reveal the consistency between the zoning of hydrochemical types of modern saline lake water and climatic zoning and give climatic parameters under the conditions of typical cold phase (mirabilite and natron), warm phase (thenar-dite) and slightly warm phase (bloedite) saline lake deposition. 展开更多
关键词 Saline lake sediments HYDROCHEMISTRY palaeoclimatic indicator QUATERNARY
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A 50-years record of dichloro-diphenyl-trichloroethanes and hexachloro-cyclohexanes in lake sediments and penguin droppings on King George Island, Maritime Antarctic 被引量:6
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作者 SUN Li-guang YIN Xue-bin +1 位作者 PAN Can-ping WANG Yu-hon 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2005年第6期899-905,共7页
Since the ban on the use of organochlorine pesticides (OCPs) such as dichloro-diphenyl-trichloroethane (DDT) and hexachlorocyclohexane(HCH) in agriculture, their levels have generally dropped. In a number of cas... Since the ban on the use of organochlorine pesticides (OCPs) such as dichloro-diphenyl-trichloroethane (DDT) and hexachlorocyclohexane(HCH) in agriculture, their levels have generally dropped. In a number of cases, however, the levels of these OCPs were found to be unchanging or even increasing after the ban. With the aim to unveil the possible causes of these exceptions, we collected two lake cores from King George Island, West Antarctica, and determined their accumulation flux profiles and temporal trends of these OCPs. In the lake core sediments with glacier meltwater input, the accumulation flux of DDT shows an abnormal peak around 1980s in addition to the expected one in 1960s. In the lake core sediments without glacier meltwater input, the accumulation flux of DDT shows a gradual decline trend after the peak in 1960s. This striking difference in the DDT flux profiles between the two lake cores is most likely caused by the regional climate warming and the resulted discharge of the DDT stored in the Antarctic ice cap into the lakes in the Antarctic glacier frontier. Furthermore, to investigate the change of OCPs loadings in the Antarctic coastal ecosystem, we reconstructed the HCH and DDT concentration profiles in penguin droppings and observed a gradual increase for the former and a continuous decrease for the latter during the past 50 years. The increase of HCH seems to be due to the regional warming from the early 1970s and the resulted HCH discharge to the coastal ecosystem by glaciers' meltwater and the illegal use of HCH in the Southern Hemisphere in the recent decade. The different temporal trends of HCH and DDT accumulation rate in the lake core with glacier meltwater input and the aged penguin droppings can be explained by their different water-soluble property. 展开更多
关键词 organochlorine pesticides(OCPs) DDT and HCH lake sediments penguin droppings temporal trend climate warming
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The climatic and hydrological changes and environmental responses recorded in lake sediments of Xinjiang,China 被引量:5
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作者 Long MA JingLu WU Jilili Abuduwaili 《Journal of Arid Land》 SCIE 2011年第1期1-8,共8页
Based on the analyses of environmental proxy data in lake sediments and instrumental records of Xinjiang in northwest China, the Holocene climate and hydrological variability and its environmental responses were studi... Based on the analyses of environmental proxy data in lake sediments and instrumental records of Xinjiang in northwest China, the Holocene climate and hydrological variability and its environmental responses were studied in different time scales and regions. The results showed that the Holocene climate variability had obvious differences between the north and south of Xinjiang. In northern Xinjiang, the Holocene climate was dry in the early period, humid in the middle period, and then changed to dry in the late period. However, the climate transition times were not consistent in different regions. In southern Xin- jiang, although there were many different types of climate change patterns inferred from different catch- ments, the warm and wet climate was recorded in most lake sediments in the middle Holocene. According to comparisons of some millennium scale records in lake sediments, the climate was warm and dry in the past 100 years. It can be concluded the climate showed a trend of aridity in Holocene. Especially in recent 50 years, the lake area has been shrinking rapidly because of the population growth and social economic development, which brings some environmental problems. Lake level and area changes were sensitively affected by the climate variation in geological history of Xinjiang and the lake level will continue to shrink because of the drought climate and strengthened human activities. 展开更多
关键词 HOLOCENE climate variation lake level lake sediment arid environment
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Environmental changes during modern period from the record of Gaoyou Lake sediments, Jiangsu 被引量:5
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作者 LI Shuheng FU Guanghe GUO Wei HE Huachun ZHANG Zhenke 《Journal of Geographical Sciences》 SCIE CSCD 2007年第1期62-72,共11页
Based on analysis of parameters of cores taken from Gaoyou Lake, including magnetic susceptibility, grain-size characteristics and sedimentary rate, environmental changes during the modern period were examined with th... Based on analysis of parameters of cores taken from Gaoyou Lake, including magnetic susceptibility, grain-size characteristics and sedimentary rate, environmental changes during the modern period were examined with the assistance of historical records and Gaoyou Lake water level materials. It is concluded that during the modern period a higher value of magnetic susceptibility and a lower sediment grain size coincided with a wet climate, while a lower value of magnetic susceptibility and a higher grain size were related with a dry climate. The results indicate that the climate in the 123 years period from 1880 to 2003AD can be divided into four stages: two low water level stages (1880-1915AD, 1948-1981AD) and two high water level stages (1915-1948AD, 1981-2003AD). It appears that the regional climate generally underwent a dry-wet-dry-wet pattern in 30-year cycles. At present, it is at the end of a wet period, so the regional climate is expected to become dry in the near future. This conclusion corresponds with the climate records in the historical literature of the Gaoyou area, and it also matches with the climatic changes in North Jiangsu area. 展开更多
关键词 Gaoyou lake environmental changes lake sediments
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Preparation and Properties of Ceramic Facing Brick from East-lake Sediment 被引量:2
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作者 吴建锋 LENG Guanghui +3 位作者 XU Xiaohong ZHANG Yaxiang LAO Xinbin Li Kun 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2012年第1期154-159,共6页
In order to utilize solid wastes, ceramic facing brick was made form East-lake sediment and some additives. The strength and freeze-thaw resistance of the samples were tested, and the crystal phases and microstructure... In order to utilize solid wastes, ceramic facing brick was made form East-lake sediment and some additives. The strength and freeze-thaw resistance of the samples were tested, and the crystal phases and microstructures were studied by XRD and SEM. The results indicate that the samples have a wide firing temperature range. The main crystal phases are CaA12SizOs, a-Al203, Fe203, which distribute uniformly in the samples. The sample have the best properties in the series 'Ca-A1-Si', and water absorption (Wa), porosity (Pa), bulk density (D), bending strength and compressive strength are 7.24%, 15.82%, 2.19 g.cm"3, 45.57 MPa and 56.81 MPa respectively, when the addition amount of East-lake sediment is 80% and the firing temperature is 1 100 ~C. In the series 'K-A1-Si', the sample with the best properties was obtained when addition amount of East-lake sediment was 70% and firing temperature was 1 060 ~C. The water absorption, porosity, bulk density, bending strength and compressive strength are 7.62%, 16.37%, 2.15 g ~ cm"3, 39.26 MPa, and 50.81 MPa respectively. They all come up to the national standardization, and meet the needs of manufacturing production. 展开更多
关键词 East-lake sediment ceramic facing brick pressing method structures and functions
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A concise overview on historical black carbon in ice cores and remote lake sediments in the northern hemisphere 被引量:1
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作者 Poonam Thapa JianZhong Xu Bigyan Neupane 《Research in Cold and Arid Regions》 CSCD 2021年第3期179-194,共16页
Black Carbon(BC),as a driver of environmental change,could significantly impact the snow by accelerating melting and decreasing albedo.Systematic documentation of BC studies is crucial for a better understanding of it... Black Carbon(BC),as a driver of environmental change,could significantly impact the snow by accelerating melting and decreasing albedo.Systematic documentation of BC studies is crucial for a better understanding of its spatial and temporal trends.This study reviewed the BC studies in the ice core and remote lake sediments and their sources in the northern hemisphere.The literature surveyed points to around 2.9 to 3.7 times increase of BC in the European Alps and up to a three-fold increase of BC in the Himalayan-Tibetan Plateau(HTP)after the onset of industrialization in Europe and Asia,respectively.BC concentration from Greenland ice core showed seven times increase with an interrupted trend after 1950's.South Asian emissions were dominant in the HTP along with a contribution from the Middle East,whereas Western European and local emissions were responsible for the change in BC concentration in the European Alps.In the Arctic,contributions from North America,Europe and Asia persisted.Similarly,a historical reconstruction of lake sediments records demonstrates the effects of emissions from long-range transport,sediment focusing,local anthropogenic activities,precipitation and total input of flux on the BC concentration. 展开更多
关键词 black carbon ice core lake sediment Himalayan-Tibetan Plateau ARCTIC European Alps
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Tracing the Provenance of the Huguangyan Maar Lake Sediments in Coastal Regions of South China 被引量:1
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作者 SHENG Mei WANG Xisheng +2 位作者 CHU Guoqiang CHEN Yun TANG Ling 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2015年第3期1053-1054,共2页
The Huguangyan Maar Lake(HML)(21°9'N,110°17'E),situated on the Leizhou Peninsula in the southernmost of China's Mainland,is the deepest recent crater lake among the identified volcanic structures i... The Huguangyan Maar Lake(HML)(21°9'N,110°17'E),situated on the Leizhou Peninsula in the southernmost of China's Mainland,is the deepest recent crater lake among the identified volcanic structures in the Leiqiong Volcanic Field.The bi-lobate lake. 展开更多
关键词 Pr lake Tracing the Provenance of the Huguangyan Maar lake sediments in Coastal Regions of South China REE
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The changes of pigment contents and their environmental implications in the lake sediments of Ny-lesund,Svalbard,the Arctic 被引量:4
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作者 姜珊 刘晓东 +1 位作者 徐利强 孙立广 《Chinese Journal of Polar Science》 2010年第1期60-70,共11页
According to palaeoclimatic and modern instrumental data,numerous studies have indicated that the Arctic climate has undergone a significant warming during the past 100 years,and this may lead to significant impact on... According to palaeoclimatic and modern instrumental data,numerous studies have indicated that the Arctic climate has undergone a significant warming during the past 100 years,and this may lead to significant impact on the fragile lake ecosystem.In this study,we collected a lake sediment core from the Nylesund of Svalbard and determined the concentrations of four pigments including chlorophyll derivatives,total carotenoids,oscillaxanthin and myxoxanthophyll in the sediments.Combined with other physical and chemical proxies such as calcium carbonate,total organic carbon,biogenic silicon etc.,we have reconstructed the historical changes of lacustrine primary productivity in Ny-lesund,especially for the past 100 years.The results showed that during the period of Little Ice Age(LIA),the climate was unfavorable for the growth of the lake algae,and thus the lacustrine productivity declined.This result was supported by the relatively low contents of pigment and biogenic silica in the sediments.In contrast,the contents of total organic carbon(TOC) and sediment pigments increased significantly in the upper 5 cm(-1890AD),reflecting the rapid growth of the lake algae,thus the great increase of lacustrine primary productivity,corresponding to the warming climate after LIA.However,the biogenic silica in the upper sediments still had a relatively low level,and this might be related to the growth competition with other algae species.Over the past 100 years,the ratio of Osc/Myx in the sediments decreased continuously,indicative of durative increase of myxoxanthophyll in blue-green algal pigments,and this might imply that the human activity had enhanced the nutrition level of the lake in the Arctic region. 展开更多
关键词 Arctic lake sediments Pigments Primary Productivity Climate Change.
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The Factors for Transformation between the Fractions of Speciation of Trace Metals in Lake Sediments 被引量:1
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作者 ZHANG Hui 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2017年第2期753-754,共2页
Objective Despite the fact that the bioavailability of trace metals indicated by their speciation has been an indispensable parameter in the assessment and treatment of the environmental pollution of trace metals, ma... Objective Despite the fact that the bioavailability of trace metals indicated by their speciation has been an indispensable parameter in the assessment and treatment of the environmental pollution of trace metals, many studies have suggested that the bioavailability of trace metals may change according to the conditions of the environment, and the speciation of trace metals can also transform between some fractions. These transformations are related with these factors such as the compositions, microorganism, time, and other physical-chemical conditions of the system. Our work aims to systematically investigate and probe the factors to affect the transformation aside from analysis at certain time-place. The results of these understanding and investigations can be used for reasonably determining the allocation of financial and technical resources in natural and engineered processes, with bringing about inspirations from the evolution of the speciation of the trace metals on environmental impacts. 展开更多
关键词 The Factors for Transformation between the Fractions of Speciation of Trace Metals in lake sediments lake
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The Calculation Method for the Volume of Landslides and Dammed Lake Sediments Triggered by a Strong Historical Earthquake in the Loess Plateau:A Case Study of Qiuzigou, Gansu Province, Northwest China 被引量:1
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作者 DU Peng XU Yueren +2 位作者 LI Wenqiao TIAN Qinjian CHEN Lize 《Earthquake Research in China》 CSCD 2020年第4期580-598,共19页
The quantitative calculation of the volume of large earthquake-triggered landslides and related dammed lake sediments is of great significance in the study of secondary disasters and focal parameters of strong histori... The quantitative calculation of the volume of large earthquake-triggered landslides and related dammed lake sediments is of great significance in the study of secondary disasters and focal parameters of strong historical earthquakes.In this study,the dammed lake induced by Qishan M7 earthquake(Lingtai County,Gansu Province,Northwest China)is selected as the research object.Based on the information collected from the 4 boreholes in the dammed lake area,we further take advantage of the lowlevel Unmanned Aerial Vehicle(UAV)photogrammetry and the morphology recovery method,to calculate the volume of the dammed lake and landslides,respectively.Finally,major conclusions are obtained as follows:①the AMS-14C age at the bottom of the Qiuzigou Dammed Lake sediments is 2890±30 BP,which coincides with the 780 BC Qishan earthquake;furthermore,the Qiuzigou Landslides seem to have been triggered by the earthquake,forming an enclosed dammed lake deposition environment after the upstream sediments accumulate;②the Qiuzigou landslides are opposite-sliding landslides that have blocked the river valley;in detail,landslide volumes at the right and left banks are 235×104 m3 and 229×104 m3,respectively.The length of the dammed lake is 2.6 km,with a thickness of approximately 43 m near the landslides,and the total sedimentary volume is 573×104 m3;③the erosion rate of Qiuzigou Landslide Dammed Lake is 0.44 mm/a,the accumulation rate is 15.05 mm/a,and the soil erosion modulus is 593 t/(km2/a),characterized as slight erosion.Quantitative research on the formation of landslides and dammed lakes from strong historical earthquakes is vital for increasing our understanding of the vibrational characteristics and surface action processes of these types of earthquakes. 展开更多
关键词 Earthquake-triggered landslides Earthquake dammed lake sediments 780 BC Qishan earthquake Qiuzigou Loess Plateau
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Radionuclide dating(^(210)Pb,^(137)Cs) of recent inter-dune saline lake sediment cores in the Badain Jaran Desert,Inner Mongolia,Northwest China 被引量:1
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作者 LIU Siwen CHU Guoqiang JIANG Yadong 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2014年第S1期18-19,共2页
Inter-dune lake sediment cores are ideal and unavailable materials for study climate and environmental changes of arid region.The precious dating of lake sediment cores is required for carrying out high resolution cli... Inter-dune lake sediment cores are ideal and unavailable materials for study climate and environmental changes of arid region.The precious dating of lake sediment cores is required for carrying out high resolution climate and environmental changes with these cores.The Badain Jaran inter-dune lake group embedding in the sand sea is the 展开更多
关键词 210Pb 137Cs CRS lake sediment core the Badain Jaran Desert
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The significance of lake sediments geochemistry in environmental reconstruction of south Hongshan Lake, northwestern Tibetan Plateau during the past 150 years
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作者 CHEN Ling, ZHU Li-ping, ZHANG Qing-song (Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China) 《Journal of Geographical Sciences》 SCIE CSCD 2000年第3期65-71,共2页
A 107cm piston-core (SHC-2) was drilled at the site with water depth of 5m in South Hongshan Lake, northwest Tibet in 1998. Based upon the 0.72cm/a of modern sedimentary rate that was tested by 210Pb method and also c... A 107cm piston-core (SHC-2) was drilled at the site with water depth of 5m in South Hongshan Lake, northwest Tibet in 1998. Based upon the 0.72cm/a of modern sedimentary rate that was tested by 210Pb method and also calibrated by 137Cs method as well as the 1cm interval sample cutting level, a lake sedimentary record of 150-yr old and with a resolution of 1.4 yrs was obtained. Ratio of geochemistry contents (TOC, TN, CaCO3) and concentrations of trace elements such as B, Sr, Ba, Ca, Mg, K, Na, Al, Ti, Cu, Zn, Fe, Mn, Ni, Cr, V, Pb, etc were analyzed. The values of TOC, TN, C/N, CaCO3, Sr/Ba and Fe/Mn had clear environmental significance and well reflected the environmental changes. Geochemical multi-proxies of lacustrine sediments from SHC-2 core showed that the environmental changes in this area during the past 150 years could be reconstructed as follows: Stage 1 (1850s-1880s) was a cold period; Stage 2 (1880s-1920s) was a warm period. But the variation of lake water volume was stable in the two periods. Stage 3 (1920s-1950s) was a fluctuant and transitional period in temperature, but there were a short cold period in the 1920s and a warm period in the 1930s. Stage 4 (1950s-) showed a warming tendency, though there existed a cold period from the mid 1970s to the end of the 1980s. In the view of general trend in the past 150 years, South Hongshan Lake was shrinking gradually. It showed that, from the comparison with the Guliya ice core and meteorological records of adjacent weather stations, there is difference in the variations of temperature and precipitation among different regions and altitudes in Tibetan Plateau. It is necessary to search multi-scale and high-resolution records for environmental reconstruction and comparison. 展开更多
关键词 Kunlun Mts. south Hongshan lake lake sediments GEOCHEMISTRY environmental changes
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^(210)Pb distribution characteristics in the lake sediment core at Great Wall Station,Antarctica
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作者 赵烨 徐翠华 《Chinese Journal of Polar Science》 1997年第1期35-38,共4页
The results of 210 Pb measurements in the lake sediment core from Antarctica are reported: the relative specific activities of 210 Pb in the lake sediment were found to decrease exponentially with ... The results of 210 Pb measurements in the lake sediment core from Antarctica are reported: the relative specific activities of 210 Pb in the lake sediment were found to decrease exponentially with the depth in the study area; the sedimentation rate of the lake is about 0.072 cm/a. This paper shows that 210 Pb method is applicable to Antarctic lake sediment ,and during the 1960's the atmospheric nuclear tests have an effect on the rate of 210 Pb deposition in Antarctica. 展开更多
关键词 ANTARCTICA Great Wall Station lake sediment core 210 Pb method.
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A large carbon pool in lake sediments over the arid/semiarid region, NW China 被引量:10
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作者 Jianghu Lan Hai Xu +3 位作者 Bin Liu Enguo Sheng Jiangtao Zhao Keke Yu 《Chinese Journal Of Geochemistry》 EI CAS CSCD 2015年第3期289-298,共10页
Carbon burial in lake sediments is an important component of the global carbon cycle. However, little is known about the magnitude of carbon sequestered in lake sediments over the arid/semiarid region of China(ASAC).I... Carbon burial in lake sediments is an important component of the global carbon cycle. However, little is known about the magnitude of carbon sequestered in lake sediments over the arid/semiarid region of China(ASAC).In this study, we estimate both organic and inorganic carbon burial since *AD 1800 based on nine lakes in ASAC,and discuss the most plausible factors controlling carbon burial. Our estimates show that the annual organic carbon burial rate(OCBR) ranges from 5.3 to 129.8 g cm-2year-1(weighted mean of 49.9 g cm-2year-1), leading to a standing stock of 1.1–24.0 kg cm-2(weighted mean of 8.6 kg cm-2)and a regional sum of *108 Tg organic carbon sequestered since *AD 1800. The annual inorganic carbon burial rate(ICBR) ranges from 11.4 to 124.0 g cm-2year-1(weighted mean of 48.3 g cm-2year-1), which is slightly lower than OCBR. The inorganic carbon standing stock ranges from2.4 to 26.0 kg cm-2(weighted mean of 8.1 kg cm-2),resulting in a sum of *101 Tg regional inorganic carbon burial since *AD 1800, which is slightly lower than the organic carbon sequestration. OCBR in ASAC shows a continuously increasing trend since *AD 1950, which is possibly due to the high autochthonous and allochthonous primary production and subsequently high sedimentation rate in the lakes. This increasing carbon burial is possibly related to both climatic changes and enhanced anthropogenic activities, such as land use change, deforestation, and eutrophication in the lake. Furthermore, OCBR and ICBR are expected to continuously increase under the scenario of increasing precipitation and runoff and enhanced anthropogenic activities.The results of this research show that the buried carbon in lake sediments of the ASAC region constitutes a significant and large carbon pool, which should be considered and integrated into the global carbon cycle. 展开更多
关键词 西北干旱半干旱地区 湖泊沉积物 碳库 缓冲寄存器 全球碳循环 加权平均 输出通道 显示控制
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Organic Phosphorus in Shallow Lake Sediments in Middle and Lower Reaches of the Yangtze River Area in China 被引量:24
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作者 JIN Xiang-Can WANG Sheng-Rui +1 位作者 CHU Jian-Zhou WU Feng-Chang 《Pedosphere》 SCIE CAS CSCD 2008年第3期394-400,共7页
Thirteen sediment core samples(0-10 cm) were taken from the seven lakes in the middle and lower reaches of the Yangtze River to determine the contents and distributions of organic phosphorus(P) fractions in the sedime... Thirteen sediment core samples(0-10 cm) were taken from the seven lakes in the middle and lower reaches of the Yangtze River to determine the contents and distributions of organic phosphorus(P) fractions in the sediments of the shallow lakes in the area.The organic P fractions in the sediments were in the order of moderately labile organic P(MLOP) > moderately resistant organic P(MROP) > highly resistant organic P(HROP) > labile organic P(LOP),with average proportional ratios of 13.2:2.8:1.3:1.0.LOP,MLOP,and MROP were significantly related to the contents of total organic carbon(TOC),water-soluble P(WSP),algal-available P(AAP),NaHCO3-extractable P(Olsen-P),total P(TP),organic P(OP),and inorganic P(IP).However,HROP was significantly related to OP and weakly correlated with TOC,WSP,AAP,Olsen-P,TP or IP.This suggested that organic P,especially LOP and MLOP in sediments,deserved even greater attention than IP in regards to lake eutrophication.In terms of organic P,sediments were more hazardous than soils in lake eutrophication.Although OP concentrations were higher in moderately polluted sediment than those in heavily polluted sediment,LOP and MLOP were higher in the heavily polluted sediment,which indicated that heavily polluted sediment was more hazardous than moderately polluted sediment in lake eutrophication. 展开更多
关键词 化学萃取 磷元素 生物利用度 湖泊 沉淀物
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Climatic periodicities recorded in lake sediment magnetic susceptibility data:Further evidence for solar forcing on Indian summer monsoon 被引量:3
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作者 Anish Kumar Warrier Kizhur Sandeep Rajasekharaiah Shankar 《Geoscience Frontiers》 SCIE CAS CSCD 2017年第6期1349-1355,共7页
The Indian summer monsoon exhibits considerable spatio-temporal variability.It is therefore important to understand its dynamics and the inherent periodicities.In this study,we have performed spectral and wavelet anal... The Indian summer monsoon exhibits considerable spatio-temporal variability.It is therefore important to understand its dynamics and the inherent periodicities.In this study,we have performed spectral and wavelet analyses of magnetic susceptibility data for sediments from Thimmannanayakanakere(TK)-a small lake in southern India.The main objective of this investigation is to identify and explain the possible origin of the prominent periodicities present in the magnetic susceptibility data.Significant periodicities in the TK χ_(lf)data are centered at 906,232,147,128,96,61,54 and 44 years,which might have a solar origin.The wavelet power spectrum of the raw and detrended χ_(lf)data confirms the findings of spectral analysis and also provides temporal variations of the significant cyclicities during the past3700 cal.years B.P.Positive correlation is documented between sunspot activity and TK xif data;crossspectral analysis of the reconstructed sunspot data and TK xif data suggest that there is a strong coherence between the two datasets as significant periodicities are documented in both.There is a good match between the TK xif and the reconstructed total solar irradiance data for the past 1200 years.However,an out-of-phase relationship is documented at certain time-intervals,which may be attributed to uncertainties in the age-depth model.The results obtained from this study show that solar variations are the main controlling factor of the southwest monsoon and,like other archives from different regions in India,the TK lake sediments have also recorded these solar signatures. 展开更多
关键词 Spectral analysis PERIODICITY Paleorainfall lake sedimentS Magnetic susceptibility SOUTHERN India
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Lake Sediments from Dianchi Lake:A Phosphorus Sink or Source? 被引量:11
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作者 GAOLi YANGHao ZHOUJian-Min LüJun-Jie 《Pedosphere》 SCIE CAS CSCD 2004年第4期483-490,共8页
Dianchi Lake is a highly eutrophic lake in southwestern China where phosphorus (P) is the limiting element for eutrophication and where lake sediments play an important role in the P cycle. One hundred and eighteen si... Dianchi Lake is a highly eutrophic lake in southwestern China where phosphorus (P) is the limiting element for eutrophication and where lake sediments play an important role in the P cycle. One hundred and eighteen sites were sampled throughout Dianchi Lake in 2002 to investigate the P loading of the lake sediments, while fresh surface sediments were studied in the laboratory to clarify its role for phosphorus. The results showed that concentrations of total phosphorus (TP) in sediments were very high, with a maximum value of 6.66 g kg-1, and decreased with sediment depth. P adsorption on surface sediments was rapid with adsorption amounts higher in acidic than in alkaline conditions. The release experiments showed that P release increased as pH rose from 7.0 to 10.5. Additionally, compared with aerobic conditions, P release was much higher under anaerobic conditions, especially with low P content in the lake water. At present, the sediments in Dianchi Lake still function as a sink for phosphorus at high P levels in lake water. However, if the external P load was reduced and P content in lake water became low, the sediment would have a large potential for P release under anaerobic conditions. 展开更多
关键词 湖泊污染 沉积物 吸附性 富营养
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Anthropogenic Effect on Deposition Dynamics of Lake Sediments Based on ^(137)Cs and ^(210)Pb_(ex) Techniques in Jiuzhaigou National Nature Reserve,China 被引量:3
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作者 LIANG Kangkang HU Xinxin +2 位作者 LI Shiguang HUANG Chengmin TANG Ya 《Chinese Geographical Science》 SCIE CSCD 2014年第2期180-190,共11页
Radionuclide dating techniques characterized by137Cs and210Pbex have recently been applied in the study of lake sediments around the world.In this study,a chronological series of sediment cores was established based o... Radionuclide dating techniques characterized by137Cs and210Pbex have recently been applied in the study of lake sediments around the world.In this study,a chronological series of sediment cores was established based on137Cs and210Pbex analyses along with the evaluation of sediment properties,such as particle size distribution,total organic carbon(TOC),carbonate content,and acid-insoluble residue,to study sediment accumulation rates,sediment sources,and responses to human activities in the Jiuzhaigou National Nature Reserve in southwestern China.In terms of the particle size distribution of sediments,silt content was the highest,and clay and sand contents were relatively low.The sediments displayed high TOC contents because of the significant amounts of vegetation grown in the lakes.The carbonate content was also high due to the overall geological background of carbonates in Jiuzhaigou.Carbonate content tended to decline from top to bottom in the sediment cores,whereas the acid-insoluble residue tended to increase.These results suggested that the depth variation of the environmental parameters of the sediments in two lakes in Jiuzhaigou would correspond to each other.The results indicated that the sediment rate of Jiuzhaigou was generally high with strong siltation,indicating that serious soil loss was induced by intensive human activities in the basin over the past decades.The increases in the mass accumulation rate,contents of acid-insoluble residue,and mean particle size during the periods of 1840–1900s,late 1930s–early 1950s,1966–1978,and2003–2006 revealed the occurrence of severe soil and water loss as a result of extensive agricultural expansion,large-scale deforestation,and road construction in Jiuzhaigou.The deposition rate and the properties of lacustrine sediments could reflect the significant impact of human activities on lake sedimentation during Jiuzhaigou′s history. 展开更多
关键词 国家级自然保护区 湖泊沉积物 中国西南地区 测年技术 九寨沟 沉积动力学 人为影响 碳酸盐含量
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Characterization of depth-related microbial communities in lake sediment by denaturing gradient gel electrophoresis of amplified 16S rRNA fragments 被引量:5
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作者 ZHAO Xingqing YANG Liuyan +4 位作者 YU Zhenyang PENG Naiying XIAO Lin YIN Daqiang QIN Boqiang 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2008年第2期224-230,共7页
The characterization of microbial communities of different depth sediment samples was examined by a culture-independent method and compared with physicochemical parameters, those are organic matter (OM), total nitro... The characterization of microbial communities of different depth sediment samples was examined by a culture-independent method and compared with physicochemical parameters, those are organic matter (OM), total nitrogen (TN), total phosphorus (TP), pH and redox potential (Eh). Total genomic DNA was extracted from samples derived from different depths. After they were amplified with the GC-341 f/907r primer sets of partial bacterial 16S rRNA genes, the products were separated by denaturing gradient gel electrophoresis (DGGE). The profile of DGGE fingerprints of different depth sediment samples revealed that the community structure remained relatively stable along the entire 45 cm sediment core, however, principal-component analysis of DGGE patterns revealed that at greater sediment depths, successional shifts in community structure were evident. The principle coordinates analysis suggested that the bacterial communities along the sediment core could be separated into two groups, which were located 0-20 cm and 21-45 cm, respectively. The sequencing dominant bands demonstrated that the major phylogenetic groups identified by DGGE belonged to Bacillus, Bacterium, Brevibacillus, Exiguobacterium, γ-Proteobacterium, Acinetobacter sp. and some uncultured or unidentified bacteria. The results indicated the existence of highly diverse bacterial community in the lake sediment core. 展开更多
关键词 16S rRNA denaturing gradient gel electrophoresis (DGGE) lake Taihu microbial diversity sediment vertical distribution
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Lake sediment resuspension and caused phosphate release——a simulation study 被引量:14
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作者 Fan, CX Zhang, L Qu, TC 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2001年第4期406-410,共5页
Intact sediment cores and wet/dried surficial sediments sampled from the two sublakes in Taihu Lake, Meiliang Bay and Wuli Lake, were incubated in the laboratory to determine the effects of resuspension on internal ph... Intact sediment cores and wet/dried surficial sediments sampled from the two sublakes in Taihu Lake, Meiliang Bay and Wuli Lake, were incubated in the laboratory to determine the effects of resuspension on internal phosphorus loading by simulating different resuspension events. Soluble reactive phosphorus (SRP) release from undisturbed core sediment sampled in the Meiliang Bay and Wuli Lake in July 1998 was 1.53 mg/m(2) and 2.24 mg/m(2) within 4 days, respectively. However during one hour experimental simulation of resuspension, SRP increased by 0.041 mg/L and 0.077 mg/L in die above cores, which indicate that a typical resuspension event in the take would be accompanied by the release of 10.77 mgSRP/m(2) and 23.1 mgSRP/m(2), respectively. The internal phosphorus loading induced by resuspensian is estimated to be 8 - 10 times greater than the release from undisturbed sediment. SRP release from the dried sediments during simulation of resuspension was mainly dependent on the disturbing intensity. Only when the wind strength gets to certain level, the influence of wind speed on phosphorus release appears significant, indicating that an exchangeable P pool, capable of altering equilibrium conditions in the take areas, is built up under strongly wind-exposed resuspension events. 展开更多
关键词 sediment resuspension simulation phosphate release Taihu lake
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