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Spatially Different Nutrient Histories Recorded by Multiple Cores and Implications for Management in Taihu Lake, Eastern China

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Chinese Geographical Science 2013年第5期23卷 537-549页

作者： CAO Yanmin zhang enlou Peter LANGDON LIU Enfeng SHEN Ji State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography&LimnologyChinese Academy of Sciences University of Chinese Academy of Sciences School of Geography University of Southampton

The Taihu Lake,a large shallow lake in the floodplain of the Changjiang(Yangtze) River in the eastern China,is faced with challenging ecological problems resulting from eutrophication,which has affected the regional freshwater supply of a large *** efforts have been made to assess the nutrient evolution histories in the northern bays,little is known regarding nutrient histories in different parts across the entire lake *** this paper,we present nutrient histories for different parts of the lake based on chironomid transfer functions applied to four short cores obtained from the northern,western and eastern regions of the *** chironomid-inferred total phosphorus(CI-TP) concentrations were compared with the phosphorus concentrations obtained by using instrumental and sedimentary *** results suggest that trophic evolution histories were asynchronous throughout the lake during the past decades in response to different ecological regimes controlled by the nutrient input,wind direction and shoreline *** restoration of aquatic plants may be an effective option for the management of lake rehabilitation to ′natural′ *** the multiple factors controlling the biotic communities in such a large and complex lake,combined analyses among the multi-proxies encountered in the sediments are necessary for comprehensive insight into paleolimnological *** spatial heterogeneity in the ecological trajectories within this complicated ecosystem suggests that different management practices should be undertaken for specific lake zones in the Taihu Lake.

关键词： nutrient history chironomid multiple cores transfer function Taihu Lake

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Black carbon record of the wildfire history of western Sichuan Province in China over the last 12.8 ka

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Frontiers of Earth Science 2016年第4期10卷 634-643页

作者： Weiwei SUN enlou zhang Ji SHEN Rong CHEN Enfeng LIU State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and Limnology Chinese Academy of Sciences Nanjing 210008 China University of Chinese Academy of Sciences Beijing 100049 China

Wildfire is recognized as a critical Earth system process which affects the global carbon cycle, atmospheric chemistry, and ecosystem dynamics. Estimat- ing the potential impact of future climate change on the incidence of fire requires an understanding of the long-term interactions of fire, climate, vegetation, and human activity. Accordingly, we analyzed the black carbon content and the pollen stratigraphy of sediments spanning the past 12.8 ka from Lake Muge Co, an alpine lake in western Sichuan Province, in order to determine the main factors influen- cing regional fire regimes. The resuks demonstrate that wildfires occurred frequently and intensively during the late deglaciation and the early Holocene when the regional vegetation was dominated by deciduous forests. Wildfire occurrence decreased significantly during the Holocene climatic optimum between 9.2 and 5.6 cal ka BP. Overall, the wildfire history of western Sichuan Province is similar to that of the Chinese Loess Plateau and of East Asia as a whole, suggesting that regional-scale fires depended mainly on changes in the intensity of the Asian summer monsoon. In addition, the fire regime of western Sichuan Province may have been influenced by the establishment of human settlement and agriculture in western Sicbuan Province and the southeastern Tibetan Plateau after about 5.5 cal ka BP, and by an intensification of cereal cultivation coupled with population expansion in southwestern China during the last two millennia.

关键词： black carbon wildfire summer monsoon,human activity Holocene Lake Muge Co

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One century sedimentary record of lead and zinc pollution in Yangzong Lake, a highland lake in southwestern China

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Journal of Environmental Sciences 2012年第7期24卷 1189-1196页

作者： enlou zhang Enfeng Liu Ji Shen Yanmin Cao Yanling Li State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and LimnologyChinese Academy of SciencesNanjing 210008China

Reconstruction of trace metal pollution histories and sources may help us to regulate current pollutant discharge. This is especially important for the highland lakes in southwestern China, which are facing trace metals pollution. We present sedimentary records of 11 metals accumulated in Yangzong Lake since the 1870＇s, a highland lake in southwestern China. Pollution of lead and zinc （Pb and Zn） was differentiated based on principal component analysis, geochemical normalization, and lead isotope ratios. Nearly all the metals as well as grain size composition show generally constant values before the mid-1980＇s, denoting stable detrital input in the catchment. Fluctuations in the concentrations of the metals as well as grain size composition since the mid-1980＇s indicate an increase in soil erosion with strengthened human disturbance in the catchment. After geochemical normalization, Pb and Zn showed constant values before 1990 AD and then a gradual increase in parallel with the variations in 2~spb/~~6pb and 2~7pb/2~6pb ratios, indicating that Pb and Zn pollution occurred. Combining the data of 20PPb/206Ppb and 207Pb/206Pb ratios in the sediments of Yangzong Lake, leaded gasoline, Pb-Zn ore and coal, and consumption or production historical trends, we deduced that the enhanced Pb and Zn pollution in Yangzong Lake is caused primarily by ore mining and refining.

关键词： Pb, Zn pollution temporal trend sediment Yangzong Lake

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Environmental changes during early-middle Holocene from the sediment record of the Chaohu Lake,Anhui Province

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Chinese Science Bulletin 2008年第S1期53卷 153-160页

作者： XinYuan Wang GuangSheng zhang Li Wu XiHui zhang enlou zhang XiaYun Xiao QingFeng Jiang Anhui Normal Univ Coll Territorial Resources and Tourism Wuhu 241000 Peoples R China.

A typical lake sediment core is obtained from the Chaohu Lake in the lower reaches of the Yangtze River,Anhui Province,*** timing scale is constrained by AMS 14 C dating *** proxies such as pollen and grain size in the core are analyzed to reconstruct the environment changes at this site approximately between 9870 and 2170 cal.a *** results indicate that at the research area, the climate in the early-middle Holocene had evolved through 3 *** 9870 to 6040 cal.a BP, proxy records show a warm and dry climate with low water levels after the late-glacial *** this stage,cool and dry events occurred at about 8910 and 6060-6030 cal.a ***,between 6040 and 4860 cal.a BP,the climate was humid and vegetation was more flourishing in the Chaohu Lake *** Holocene Optimum occurred at 5840-5500 cal.a BP in the Chaohu Lake,showing the best condition of water and *** Decline occurred at the period of 5380-4930 cal.a *** 4860 cal.a BP,the climate was warm and dry through 2170 cal.a BP as shown in both pollen spectrum and grain-size *** obvious dry events occurred in 3760 and 2170 cal.a BP,*** 2170 cal.a BP,the water level of the Chaohu Lake reached the lowest as the lakebed possibly exposed. Such lake sediment observations are consistent with the historical records in this area.

关键词： lake sediment environmental change pollen grain-size the early and middle Holocene the Chaohu Lake Basin

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A high-resolution climatic change since Holocene inferred from multi-proxy of lake sediment in westerly area of China

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Chinese Science Bulletin 2007年第14期52卷 1970-1979页

作者： JIANG QingFeng SHEN Ji LIU XingQi zhang enlou XIAO XiaYun Nanjing Institute of Geography and Limnology Chinese Academy of Sciences Nanjing 210008 China Geographical Science School Nantong University Nantong 226007 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

Multi-proxy data are presented and a discuss is made of paleoclimatic and paleoenvironmental changes during Holocene from a 225-cm-long sediment core from Wulungu Lake, located in westerly area of China. The chronology is constructed from six AMS radiocarbon dates on the bulk organic matter. Analyses of pollen, TOC, TN, δ 13Corg, ostracod assemblages and the shell stable isotopes, suggest Holocene climate pattern as follows: temperate and dry (10.0―7.6 cal. ka BP)-warm and wet (7.6―5.3 cal. ka BP) -warm and moist (5.3―3.6 cal. ka BP) -temperate and dry (3.6―2.1 cal. ka BP)-temperate and moist (2.1―1.3 cal. ka BP) -cool and dry (1.3 cal. ka BP―present). With the climatic change, Wulungu Lake experienced two large-scale retreat (5.3―3.6 cal. ka BP and 1.3 cal. ka BP―present) and an obvious transgression (7.6―5.3 cal. ka BP). The records of climatic and environmental evolution of Wulungu Lake were in good accordance with those of adjacent areas. It responded to regional environmental change, global abrupt climate events and followed the westerly climate change mode.

关键词：全新世古代气候古代环境湖泊

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Paleosandstorm characteristics and lake evolution history deduced from investigation on lacustrine sediments——The case of Hongjiannao Lake, Shaanxi Province

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Chinese Science Bulletin 2005年第20期50卷 2355-2361页

作者： SHEN Ji WANG Yong YANG Xiangdong zhang enlou YANG Bao JI Junfeng Nanjing Institute of Geography and Limnology Chinese Academy of Sciences Nanjing 210008 China Graduate School Chinese Academy of Sciences Beijing 100039 China Key Laboratory of Ice and Cold Region Environment Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China Institute of Surfacial Geochemistry State Laboratory of Mineral Deposits Research Department of Earth Sciences. Nanjing University Nanjing 210009 China

Sediment cores from desert lakes serve as good records of the frequency and intensity of sandstorms in his- tory. By multi-proxy analysis of grain-size, magnetic suscep- tibility, TOC and Rb/Sr ratio, the paleosandstorm character- istics and lake evolution history in Yulin Area for the past 80 years. are discussed in this article. It is revealed that Hong- jiannao Lake formed in about 1928 A.D. and in its initial stage sandstorms were prevalent with three extremes taking place in 1936 A.D., 1939 A.D. and 1941 A.D.. During the ex- pansion period of 1952―1960 A.D., inflow waters to the lake increased sharply and a lot more weathered materials were carried into the lake. The frequency and intensity of sand- storms have reduced a lot since 1960s and the “double peaks” feature of the grain-size frequency curve has changed into the “single peak” feature. Study on the catchment ecol- ogy of the lake shows that the occurrence of sandstorms has been effectively restrained by the forest plantation and water and soil conservation.

关键词：陕西省湖泊沉积物沙暴磁化系数进化历史

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A subfossil chironomid-total phosphorus inference model for lakes in the middle and lower reaches of the Yangtze River

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Chinese Science Bulletin 2006年第17期51卷 2125-2132页

作者： zhang enlou Alan Bedford Richard Jones SHEN Ji WANG Sumin TANG Hongqu Nanjing Institute of Geography & Limnology Chinese Academy of Sciences Nanjing 210008 China Natural Geographical and Applied Sciences Edge Hill College Ormskirk L394QP England Department of Geography University of Exeter Exeter EX4 4RJEngland School of Biology Nankai University Tianjin 300017 China

The results of an investigation into the relationship between surface sediment subfossil chi- ronomid distribution and water quality are presented. Data from 30 lakes in the middle and lower reaches of the Yangtze River indicate that the nutrient gradi- ent was the major factor affecting the distribution of chironomids across these sites. Canonical corre- spondence analysis (CCA) revealed that of 12 sum- mer water environmental variables, total Phosphorus was most important, accounting for 20.1% of the variance in the chironomid data. This was significant enough to allow the development of quantitative in- ference models. A TP inference model was devel- oped using weighted averaging (WA), partial least squares (PLS) and weighted averaging partial least squares (WA-PLS). An optimal two-component WA-PLS model provided a high jack-knifed coeffi- cient of prediction for conductivity r 2jack = 0.76, with a low root mean squared error of prediction (RMSEPjack = 0.13). Using this model it is possible to produce long-term quantitative records of past water quality for lacustrine sites across the middle and lower reaches of the Yangtze River, which has important implications for future lake management and eco- logical restoration.

关键词：湖泊亚化石摇蚊推理模型长江中下游地区

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A 16000-year pollen record of Qinghai Lake and its paleoclimate and paleoenvironment

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Chinese Science Bulletin 2002年第22期47卷 1931-1936页

作者： LIU Xingqi SHEN Ji WANG Sumin YANG Xiangdong TONG Guobang zhang enlou Key Laboratory of Lake Sedimentation and Environment Nanjing Institute of Geography and LimnologyChinese Academy of SciencesNanjing 210008China Institute of Hydrological and Environmental Geology Chinese Academy of Geological SciencesZhengding 050803China

The paleoclimate and paleoenvironment of Qinghai Lake indicated by a 16000-year pollen record are as follows. It was very cold and dry before 15200 years. During the Late Glacial, the climate varied from colder and semiarid to cool and semi-humid and fluctuated frequently but with little amplitude. Three cold events in the periods of 13400-13000, 11600-12000, and 11000-10400 aBP respectively correspond to the Oldest Dryas, Older Dryas and Younger Dryas events, whereas the two warm periods between them, 12000-13000 and 11600-11000 aBP, respectively correspond to Boiling and Allerod periods. The temperature increased abruptly after the Younger Dryas event, and then the climate gradually turned to be warm and wet from warm and semiarid. In the Holocene, the largest amplitude of cold event that occurred at ca. 8200 aBP is quite prominent. The Holocene climatic optimum culminated at 6700 aBP. After 2100 aBP, the climate tended to be cold and dry, keeping on up to now. Palaeoclimatic evolution and events of

关键词： Qinghai Lake pollen Lateglacial paleoclimate and paleoenvironment.

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A 1000-year chironomid-based salinity reconstruction from varved sediments of Sugan Lake,Qaidam Basin,arid Northwest China,and its palaeoclimatic significance

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Chinese Science Bulletin 2009年第20期54卷 3749-3759页

作者： CHEN JianHui CHEN FaHu zhang enlou BROOKS Stephen J ZHOU AiFeng zhang JiaWu MOE Key Laboratory of Western China's Environmental Systems Lanzhou University Lanzhou 730000 China State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and Limnology Chinese Academy of Sciences Nanjing 210008 China Department of Entomology Natural History Museum London SW7 5BD UK

A 1000-year high-resolution(～10 years) chironomid record from varved sediments of Sugan Lake,Qaidam Basin on the northern Tibetan Plateau,is *** chironomid assemblages are mainly composed of the relatively high-saline-water taxa Psectrocladius barbimanus-type and Orthocladius/Cricotopus,and the relatively low-saline-water taxa Procladius and Psectrocladius *** in the chironomid fauna and inferred salinities suggest that over the last millennium,the Sugan Lake catchment has alternated between contrasting climatic conditions,having a dry climate during the period 990―1550 AD,a relatively humid climate during the Little Ice Age(LIA)(1550―1840 AD),and a dry climate again from 1840 AD *** the decadal to centennial scale,a wet event around 1200―1230 AD,interrupting the generally arid period(990―1550 AD),and a dry event around 1590―1700 AD,punctuating the generally humid period(1550―1840 AD),are clearly *** in the chironomid-based salinity time series indicate a highly unstable climate during the LIA when salinity fluctuations were of greater magnitude and higher *** effective moisture evolution in the Sugan Lake catchment during the last millennium reconstructed by chironomid analysis is in broad agreement with previous palaeo-moisture data derived from other sites in arid Northwest China(ANC).The LIA,characterized by generally humid conditions over the west-erly-dominated ANC was distinctly different from that in monsoonal China,implying an "out-of-phase" relationship between moisture evolution in these two regions during the past 1000 years.

关键词：西北干旱地区柴达木盆地古气候意义沉积物中国盐度纹层

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Environmental changes during the past 13500 cal. a BP deduced from lacustrine sediment records of Lake Qinghai, China

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Chinese Journal Of Geochemistry 2011年第4期30卷 479-489页

作者： WANG Yong SHEN Ji XU Xingna LIU Xingqi SIROCKO Frank zhang enlou JI Junfeng State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and Limnology Nanjing 210008 China Max Planck Institute of Chemistry Mainz 55020 Germany Institute of Geoscience University ofMainz Mainz 55099 Germany School of Geographical Science Southwest University Chongqing 400715 China Department of Earth Sciences Nanjing University Nanjing 210093 China

A 475-cm long sediment core (QH-2005) from Lake Qinghai was used to carry out multi-proxy analysis of δ18O and body length of ostracod valves and redness and grain size of sediments, in order to reconstruct environ-mental changes during the past 13500 cal. a BP. The age model was based on 6 14C dates for bulk orgnic carbon (BOC) and 2 14C dates for lignin. The lignin 14C dates are apparently younger than the corresponding layers' BOC 14C dates, indicating that the reservoir age varied from 728 to 1222 a since the Late Glacial and from 2390 to 2490 a immediately before the pre-bomb era. Hence, the 14C age model for Core QH-2005 was corrected by the changing reservoir age. Ostracod δ18O values were primarily related to dilution and evaporative enrichment of the lake water. The reconstructed salinity based on ostracod body length coincides well with ostracod δ18O values. High redness and mean grain size (MZ) values indicate increased riverine supply to Lake Qinghai associated with increasing monsoon rainfall. Multi-proxy results show that climate during 13500-10900 cal. a BP was relatively cold and dry with fre-quent short-term fluctuations; a warm and wet climate began at about 10900 cal. a BP and culminated around 6500 cal. a BP as a result of monsoon strengthening; the climate became cold and dry afterwards and has remained rela-tively stable since 3400 cal. a BP. Our data also reveal short-term (millennial/centennial timescales) climatic fluctua-tions including: Younger Dryas events, ice-rafting events 8 and 1 (by ～11000 cal. a BP and ～1600 cal. a BP respec-tively), 8200 cal. a BP cold event, Little Ice Age and the Medieval Warm Period.

关键词： CAL 湖泊沉积记录青海湖 BP 环境平均晶粒尺寸气候变化中国

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