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Seasonal variation of potential denitrification rates of surface sediment from Meiliang Bay, Taihu lake, china

Journal of environmental sciences 2010年第7期22卷 961-967页

作者： Jicheng Zhong, Chengxin Fan, Guofeng Liu, Lei Zhang, Jingge Shang, Xiaozhi Gustate key {2. of lake science and environment, nanjing institute of geography and limnology, Chinese academy of sciences, nanjing 2.0008, china. [a] state key {2. of lake science environment Nanjing Institute of Geography limnology Chinese Academy of Sciences Nanjing 210008 China

The regulatory effects of environmental factors on denitrification were studied in the sediments of Meiliang Bay, Talhu lake, in a monthly sampling campaign over a one-year {2.od. Denitrification rates were measured in slurries of field samples and enrichment ex{2.ments using the acetylene inhibition technique. Sediment denitrification rates in inner bay and outer bay ranged from 2.8 to 51.5 nmol N2.（g dw （dry weight）·hr） and from 1.5 to 81.1 nmol N2.（g dw·hr）, respectively. Sediment denitrification rates were greatest in the spring and lowest in the summer and early autumn, due primarily to seasonal differences in nitrate concentration and water tem{2.ture. For each site, positive and linear relationships were regularly observed between denitrification rate and water column nitrate concentration. Of various environmental factors on denitrification that we assessed, nitrate was determined to be the key factor limiting denitrification rates in the sediments of Meiliang Bay. In addition, at the two sites denitrification rates were also regulated by tem{2.ture. The addition of organic substrates had no significant effect on denitrification rate, indicating that sediment denitrification was not limited by organic carbon availability in the sediments. Nitrate in the water column was depleted during summer and early autumn, and this su{2.ssed effective removal of nitrogen from Taihu lake by denitrification.

关键词： denitrification sediment environmental factors Taihu lake

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environmental characteristics of Mid-Holocene recorded by lacustrine sediments from lake Daihai, north environment sensitive zone, china

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science china Earth {2. 2006年第9期49卷 968-981页

作者： SUN Qianli1,2. ZHOU Jie1, SHEN Ji3, CHEN peng1,2. WU Feng1,2.& XIE Xiuping1,2.1. state key Lab of Loess and Quaternary Geology, {2. of Earth environment, Chinese academy of sciences, Xi’an 710075, china 2. Graduate University of Chinese academy of sciences, beijing 100039, china 3. nanjing institute of geography and limnology, Chinese academy of sciences, nanjing 2.0008, china 1. state key Lab of Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences Xi’an 710075 China 2. Graduate University of Chinese academy of sciences Beijing 100039 China 3. nanjing institute of geography and limnology Chinese Academy of Sciences Nanjing 210008 China

Climate proxies, such as total organic carbon and nitrogen (TOC, TN), carbonate content (CaCO3), grain-size and pollen of the sediment core retrieved from enclosed lake Daihai which lies in the north china {2. sensitive zone are analyzed to reconstruct the {2. evolution of the area based on high-resolution radiocarbon chronology. The results reveal that the TOC and TN contents of the sediments correlate well with pollen p.r.entage and pollen flux variations during the Holocene, and both reach their peak values simultaneously at 6.7―3.5 ka Bp (calendar age, 7.6―3.6 ka Bp). Since 6.7 ka Bp, both the CaCO3 and organic matter contents of the core have simultaneous variations, and their high values also occur during 6.7―3.5 ka Bp. While during 9.0―6.7 ka Bp (calendar age, 10―7.6 ka Bp) relatively lower level of organic matter content and pollen flux corre- spond to the higher level of carbonate content. The above relations suggest that during 6.7―3.5 ka Bp, the productivity and effective precipitation were greatly improved in the lake drainage area, and this would probably strengthen the hydrodynamic conditions, enhancing organic matter, pollen and carbonate inputs from terrestrial sources. Such processes would account for the enrichment of both organic matter and carbonate in the sediments. While during 9.0―6.7 ka Bp, the lower level of or- ganic matter, pollen flux but high carbonate content show depressed productivity and declined vege- tation coverage. The higher carbonate content at this stage would have probably resulted from the higher evap.r.tion ratio of the lake water under relatively drier climate conditions. Therefore, it is in- ferred that during 6.7―3.5 ka Bp, the climate was more humid with abundant rainfalls and vegetation was more flourishing in the lake Daihai area. This can be seen as Holocene Climate Optimum (HCO). As a result, this has evident discrepancies with the traditional notion that the HCO occurs at Early Holocene or early Mid

关键词： lake Daihai, Mid-Holocene, lacustrine sediments, environmental characteristics.

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Chronology of Holocene lacustrine sediments in Co Ngoin, central Tibetan plateau

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science china Earth {2. 2006年第9期49卷 991-1001页

作者： WU Yanhong1, WANG Sumin1& HOU Xinhua1,3 1. key laboratory of {2. Sedimentation and environment, nanjing institute of geography and limnology, Chinese academy of sciences, nanjing 2.0008, china 2. institute of Tibetan plateau research, Chinese academy of sciences, {12. 10085, china 3. Graduate University of Chinese academy of sciences, {12. 100039, china 1. key laboratory of {2. Sedimentation and environment Nanjing Institute of Geography and Limnology Chinese Academy of Sciences Nanjing 210008 China 2. institute of Tibetan plateau research Chinese Academy of Sciences Beijing 10085 China 3. Graduate University of Chinese academy of sciences Beijing 100039 China

Chronology is the basis for using lacustrine sediments to reconstruct the history of en-vironmental change. radioactive-nuclides such as 14C, 2.0pb and 137Cs dating are mainly used to establish the chronology for recent several ten thousand years. Because of being mixed with “dead carbon”, the measured 14C age is always older than the actual age which is recognized as “reservoir effect”. Cs is a kind of active metal element, and easy to migrate vertically in the sediment that leads to the error of the time marker. 2.0pb dating should make sure to select CIC model or CrS model. On the Tibetan plateau, most of the lakes are alkaline closed lake where Cs is more moveable in the sediment and the reservoir effect caused by “dead carbon” on 14C dating is stronger. Based on the analysis on results of 14C, 2.0pb and 137Cs of the lacustrine sediments from Co Ngoin, central Tibetan plateau, we use the simple regression method to re-calculate the 14C calendar ages, and establish the time sequence for cores CE-1 and CE-2.with result of 2.0pb CrS model for the up{2.35 cm and re-calculated 14C calendar age for sediments bellow 35 cm. Since 1400 cal. a Bp, sedimentation inter-rupted for more than 1000 years. According to this time sequence, variations of environmental proxies confidently reflect the major climatic events in Holocene.

关键词： 14C, 2.0pb and 137Cs, chronology, lacustrine sediments, climatic event, Co Ngoin, central Tibetan plateau.

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Evidence from isotopic geochemistry as an indicator of eutrophication of Meiliang Bay in lake Taihu, china

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science china Earth {2. 2006年第z1期49卷 62-71页

作者： LIN Lin, WU Jinglu & WANG Sumin nanjing institute of {2. & limnology, Chinese academy of sciences, nanjing 2.0008, china Graduate University of the Chinese academy of sciences, beijing 100039, china Chinese Acad Sci Nanjing Inst Geog & Limnol Nanjing 210008 Peoples R China Chinese Acad Sci Grad Univ Beijing 100039 Peoples R China

In this pap.r. lake Taihu, a large shallow freshwater lake in china, is chosen as an example of reconstruction of eutrophication through the comp.r.son between stable isotopes from dissolved nutrients and plants and water column nutrient p.r.meters and integration of multiple proxies in a sediment core from Meiliang Bay including TN, Tp, TOC, C/N, δ15N, δ13C, etc. Differences in aquatic plant species and trophic status between east Taihu Bay and Meiliang Bay are indicated by their variations in δ13C and δ15N of aquatic plants and δ15N of NH4+. A significant influence ofexternal nutrient inputs on Meiliang Bay is reflected in temp.r.l changes in δ 15N of NH4+ and hydro-environmental p.r.meters. The synchronous change between δ13C and δ15N values of sedimented organic matter (OM) has been attributed to elevated primary production at the beginning of eutrophication between 1950 and 1990, then recent inverse correlation between them has been caused by the uptake of 15N-enriched inorganic nitrogen by phytoplankton grown under eutrophication and subsequent OM decomposition and denitrification in surface sediments, indicating that the lake has suffered from progressive eutrophication since 1990. Based on the use of a combination of stable isotopes and elemental geochemistry, the eutrophication of Meiliang Bay in lake Taihu could be better traced. These transitions of the lake eutrophication respectively occurring in the 1950s and 1990s have been suggested as a reflection of growing impacts of human activities, which is coincident with the instrumental data.

关键词： stable carbon isotope of OM, stable nitrogen isotope, eutrophication, lake Taihu.

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preliminary study on assessment of nutrient transp.r. in the Taihu Basin based on SWAT modeling

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science china Earth {2. 2006年第z1期49卷 135-145页

作者： LAI Geying, YU Ge & GUI Feng nanjing institute of {2. & limnology, Chinese academy of sciences, nanjing 2.0008, china The Graduate School of the Chinese academy of sciences, beijing 100039, china {12. Lab of poyang lake Ecological environment and resource Development, Jiangxi Normal University, Nanchang 33002., china 1. nanjing institute of {2. & limnology Chinese Academy of Sciences Nanjing 210008 China2. The Graduate School of the Chinese Academy of Sciences Beijing 100039 China3. Key Lab of Poyang Lake Ecological Environment and Resource Development Jiangxi Normal University Nanchang 330027 China

With the Taihu Basin as a study area, using the spatially distributed and mechanism-based SWAT model, preliminary simulations of nutrient transp.r. in the Taihu Basin during the p.r.od of 1995～2.02.has been carried out. The topography, soil, meteorology and land use with industrial point pollution discharge, the loss of agricultural fertilizers, urban sewerage, and livestock drainages were all considered in the boundary conditions of the simulations. The model was calibrated and validated against water quality monitoring data from 2.01 to 2.02. The results show that the annual total productions of nitrogen (TN) and phosphorus (Tp) into {2. Taihu are 40000t and 2.00t respectively. Nutrient from the Huxi region is a major resource for {2. Taihu. The non-point source (surface source) pollution is the main form of catchment sources of nutrients into {2. Taihu,occupied TN 53% and Tp 56% respectively. TN and Tp nutrients from industrial point pollution discharge are 30% and 16%, and sewerage in both forms of point source and non-point source are TN 31% and Tp 47%. Both the loss of agricultural fertilizers and livestock drainages from the catchment should be paid more attention as an imp.r.ant nutrient source. The results also show that SWAT is an effective model for the simulation of temp.r.lly and spatially nutrient changes and for the assessment of the trends in a catchment scale.

关键词： Taihu Basin, nutrients, catchment resource inputs, SWAT model, simulation.

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New species and new records of diatoms from lake Fuxian,china

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Journal of Systematics and Evolution 2010年第1期48卷 65-72页

作者： 1 Yan-Ling LI 1 Zhi-Jun GONG 2.Chun-Chao WANG 1 Ji SHEN 1(state key {2. of lake science and environment,nanjing institute of geography and limnology,Chinese academy of sciences,nanjing 2.0008,china) 2.nanjing {12. of Geology and palaeontology,Chinese academy of sciences,nanjing 2.0008,china) (state key {2. of lake science and environment Nanjing Institute of Geography and Limnology Chinese Academy of Sciences Nanjing 210008 China) (nanjing institute of Geology and palaeontology Chinese Academy of Sciences Nanjing 210008 China) *Correspondence: Yan-Ling LI *Correspondence: *?Author for correspondence. E-mail: ylli@*** Tel.: 86-2.-86882.40 Fax: 86-2.-57713063.

One new species,four newly recorded genera,and two newly recorded species of diatoms are described from *** are Sellaphora fuxianensis ***,Sellaphora Mereschkowsky,Karayevia round & Bukhtiyarova,placoneis Mereschkowsky,Fallacia Stickle & Mann,placoneis prespanensis Levkov,Krstic & Nakov,and Fallacia lucinensis(Hustedt) *** taxa were collected from lake Fuxian in Yunnan province,*** species were observed with light and scanning electron microscopes,and their taxonomic characters are discussed.

关键词： china diatom new records new species.

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An analysis on the evolvement processes of lake eutrophication and their characteristics of the typical lakes in the middle and lower reaches of Yangtze river

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Chinese science Bulletin 2006年第13期51卷 1603-1613页

作者： CHENG Xiaoying1,2.3 & LI Shijie1 1. nanjing institute of {2. & limnology, Chinese academy of sciences, nanjing 2.0008, china 2. The key laboratory of Industrial Biotechnology, Ministry of Educa- tion, Southern Yangtze University, Wuxi 2.4036, china 3. School of Biotechnology, Southern Yangtze University, Wuxi 2.4036, china nanjing institute of {2. & limnology Chinese Academy of Sciences Nanjing China The key laboratory of Industrial Biotechnology Ministry of Education Southern Yangtze University Wuxi China School of Biotechnology Southern Yangtze University Wuxi China

According to the study on the aquatic environment of the typical lakes in the middle and lower reaches of Yangtze river, lake eutrophication is a process in which the lake ecosystem degenerates, resulting in the deterioration of the water quality due to the enrichment of the nutrients. Moreover, the succession of lake ecosystem and change of water quality both couple well with the evolvement of tro- phic state. Then the conceptual model is mentioned and ten lake states are classified. Based on these, the authors analyzed the eutrophication processes of the typical lakes in the middle and lower reaches of Yangtze river. The large lakes with taking in - send- ing out water typical of poyang lake evolve from state 1 before the 1980s into state 2 after the 1980s, the large and medium lakes typical of Taihu lake evolve from state 1-2 in the 1960s into state 8 in the 1980s then into state 9 in the 1990s, the medium and small shallow lakes typical of Honghu lake evolve from state 1 in the 1960s into state 2 after the 1980s and the small city (suburban) lakes typical of Donghu lake evolve from state 2 in the 1960s into state 9 after the 1970s. Further, the 1980s is the key con- version p.r.od of the lakes of various types typical of poyang lake, Honghu lake and Taihu lake con- verting into mesotrophic state, the 1990s is that of Taihu lake into eutrophic state and the 1970s is thatof the small city (suburban) lakes typical of Donghu lake into eutrophic state. The series of nutrient evolvement of different typical lakes are similar, but the processes are not synchronous, which is related to the various human and natural driving mechanisms in lake basins.

关键词：长江湖泊富营养化概念模型转变时期驱动机制

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role of Cell Hydrophobicity on Colony Formation in Microcystis(Cyanobacteria)

Role of Cell Hydrophobicity on Colony Formation in Microcyst...

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中国藻类学会第八次会员大会暨第十六次学术讨论会

作者： Hualin Yang~1,Yuanfeng Cai~1,Meng Xia~1,Xingyu Wang~1,Limei Shi~1,pengfu Li*~1 and Fanxiang Kong~2.1 state key {2. of pharmaceutical Biotechnology,School of Life sciences,nanjing University,nanjing 2.0093,p.r.china 2.state key laboratory of lake science and environment,nanjing institute of geography and limnology,Chinese academy of sciences,{12.,nanjing 2.0008,p.r. china

Colony formation is highly imp.r. ant for the competitive advantage of the cyanobacterium Microcystis overother phytoplankton *** laboratory-grown colonial Microcystis strains isolated from {2. Taihu(china) maintained colonial forms under the low light condition(10μE m s).The cell surface hydrophobicities of the Microcystis colonies were measured by cyanobacterial adherence to xylene in comp.r.son

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Accumulation and Fractionation of rare Earth Elements in a Soil-Wheat System

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pedosphere 2006年第1期16卷 82-90页

作者： DING Shi-Ming LIANG Tao ZHANG Chao-Sheng WANG Li-Jun SUN Qin nanjing institute of {2. ＆ limnology Chinese Academy of Sciences Nanjing 210008 （China） institute of Geographic sciences and Natural resources research Chinese Academy of Sciences Beijing 100101 （ China） Dep.r.ment of geography and {2.al Change institute National University of Ireland Galway （Ireland） state key {2. of pollution Control and resource reuse School of the Environment Nanjing University Nanjing 210093 （China）

Time series bioaccumulation of rare earth elements （rEEs） in field-grown wheat with and without a dressing of extraneous rEE fertilizer at different growth stages and fractionation of rEEs during their transp.r. in a soil-wheat system were determined. Time-dependent accumulation of extraneous rEEs was found in different p.r.s of wheat. An upward transp.r. of extraneous rEEs from roots to shoots under a soil dressing and a downward transp.r. from leaves to roots with a foliar dressing were also observed. Moreover, fractionation of rEEs occurred in the soil-wheat system. Comp.r.d to the host soil a positive Eu anomaly in the stems and grains as well as heavy rEE enrichment in the grains were found. The ability of the different wheat organs to fractionate Eu from the rEE series was ranked in the order of sterns 〉 grains 〉 leaves 〉 roots.

关键词： accumulation fractionation rare earth elements wheat

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Quantitative reconstruction of the paleosalinity at Qinghai lake in the past 900 years

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Chinese science Bulletin 2004年第7期49卷 730-734页

作者： ZHANG Enlou1,2.SHEN Ji1,WANG Sumin1,YIN Yu1,ZHU Yuxin1 & XIA Weilan1 1.key laboratory of {2. Sediment and environment,nanjing institute of geography and limnology,Chinese academy of sciences,Nan-jing 2.0008,china 2.Graduate School of Chinese academy of sciences,beijing 100039,china Correspondence should be addressed to Zhang Enlou(e-mail:elzhang@ ***) key laboratory of {2. Sediment and environment Nanjing Institute of Geography and Limnology Chinese Academy of Sciences Nanjing 210008 China Graduate School of Chinese academy of sciences Beijing 100039 China

Based on the function relationship between the shell length of Limnocythere inopinata and the salinity of its living water in Tibetan plateau lakes, the paleosalinty of Qinghai lake in the past 900 years was reconstructed through the measurement of the adult body length of Limno-cythere inopinata. Meanwhile, the paleosalinity sequence of Qinghai lake during the same p.r.od was rebuilt by the Sr/Ca ratio of the shell of Eucypris inflata combined with the Sr/Ca ratio of living ostracod valves from the species of ge-nus Eucypris inflata and the host water. The paleosalinity results obtained by two different methods were comp.r.d and assessed in this pap.r. To check the result, it was also contrasted with other historical climatic sequences of this area including tree ring and ice core. It was shown that the paleosalinity sequence rebuilt by adult ostracod body length had high reliability, and the paleosalinity reconstruction method by trace elements of ostracod shells was not suitable for Qinghai lake. From the reconstructed paleosalinty se-quence of Qinghai lake, it can be found that low salinity during 1160—12.0 AD showed the humid climate condition on the Mediaeval Warm p.r.od in this area, while the high salinity during 1410—1540 AD, 1610—1670 AD and 1770—1850 AD which was corresponding to the three cold pulses of the Little Ice Age with a dry climate condition. And the high salinity in the latest several decades was consistent with re-cent warm and dry trends of the climate in this area. The good consistency of the reconstructed palaeosalinity sequence and the precipitation sequence in this area rebuilt by tree ring proves the reconstruction of past lake salinity is reliable.

关键词：青海湖数量重建成体特异湖浪介古盐度树轮海底沉积物介形亚纲动物

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