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Nitrogen isotopic geochemical characteristics of crude oils in several basins of china

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science china Earth sciences 2005年第8期48卷 1211-1219页

作者： CHEN Chuanping1,2, MEI Bowen1 & CAO Yacheng3.1. Jianghan Petroleum University, Jingzhou 43.100, china 2. Huazhong University of science and Technology, Wuhan 43.047, china 3. nanjing {3. of soil science, chinese academy of sciences, nanjing 210008, china 1. Jianghan Petroleum University 434100 Jingzhou China 2. Huazhong University of science and Technology 430047 Wuhan China 3. nanjing institute of soil science Chinese Academy of Sciences 210008 Nanjing China

Nitrogen isotopic ratios of crude oils with different physical and chemical properties in several basins of china have been measured and their geochemistry has been studied ele-mentally combined with molecular organic geochemistry methods. The data indicate that δ 15N is in the range of ?6‰-20‰. They vary with the oils in different sedimentary types of basins. The oils forming in the limnic environment have lower δ 15N with the value of about 1‰-5‰ whereas the oils in saline or semi-saline environment have higher δ 15N, with most samples being above 10‰ and some exceeding 17‰. The average nitrogen isotopic ratio of oils from the Ordovician formation in the Tarim Basin is the lowest, with most samples having δ 15N below zero, which reflects possibly the characteristic of the oils originating mainly from the organic matter formed in marine carbonate sedimentary environment. The δ 15N distribution can be altered by fractionation. It increases obviously because of biodegradation and decreases during hydrocarbon migration. However, the effect of nitrogen isotopic fractionation in the short distance migration is uncon-spicuous.

关键词： nitrogen isotope, crude oil, sedimentary environment, isotopic fractionation, china.

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

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science china Earth sciences 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, institute of Earth Environment, chinese academy of sciences, Xi’an 710075,{3. 2. Graduate University of chinese academy of sciences, Beijing 10003.,{3. 3. nanjing institute of Geography and Limnology, chinese academy of sciences, nanjing 210008,{3. 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 environment sensitive zone are analyzed to reconstruct the environment 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 percentage 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 evaporation 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.

A high-resolution late Pleistocene record of pollen vegetation and climate change from Jingning, NW china

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science china Earth sciences 2006年第2期49卷 154-162页

作者： LI Chunhai12, TANG Lingyu1, FENG Zhaodong3.4, ZHANG Hucai2, WANG Weiguo3.& AN Chenbang3.1. nanjing institute of Geology and Palaeontology, chinese {3. of sciences, nanjing 210008, china 2. Nanjng institute of Geography and Limnology, chinese {3. of sciences, nanjing 210008, china 3. Environment and Resources College, Lanzhou University, Lanzhou 73.000, china 4. Beijing Normal University, Beijing 100875, china 1. nanjing institute of Geology and Palaeontology Chinese Academy of Sciences Nanjing 210008 China 2. Nanjng institute of Geography and Limnology Chinese Academy of Sciences Nanjing 210008 China 3. Environment and Resources College Lanzhou University Lanzhou 730000 China 4. Beijing Normal University Beijing 100875 China

With the support of 18 AMs-14C data, a high-resolution pollen record from the suancigou section at Jingning, Gansu Province was established. Our results showed that the vegetation ex-perienced a series of changes characterized by the alternative growth and decline of forest and steppe components during the period from 44.2 to 11 ka B.P. in the Jingning area. Over the period of 44―29 ka B.P. (MIs3., coniferous forests were flourishing, indicating a humid climate with the tem-perature being lower than that of the present. since 23.ka B.P., the vegetation was dominated by steppe-desert steppe under a cold and dry condition, and entered the Last Glacial Maximum domi-nated by desert steppe. several periods of the marked decrease in the arborous pollen content in suancigou well corresponded to the North Atlantic Heinrich events, especially to Heinrich event 3. further supporting that the Heinrich events were well reflected by the pollen record in the Loess Pla-teau as well.

关键词： Western Loess Plateau, pollen record, climatic change, late Pleistocene.

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

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science china Earth sciences 2006年第9期49卷 991-1001页

作者： WU Yanhong1, WANG sumin1& HOU Xinhua1,3.1. Key Laboratory of Lake sedimentation and Environment, nanjing institute of Geography and Limnology, chinese {3. of sciences, nanjing 210008, china 2. institute of Tibetan Plateau Research, chinese {3. of sciences, Beijing 10085, china 3. Graduate University of chinese {3. of sciences, Beijing 10003., china 1. Key Laboratory of Lake 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, 210Pb and 13.Cs 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. 210Pb 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, 210Pb and 13.Cs 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 210Pb CRs model for the upper 3. cm and re-calculated 14C calendar age for sediments bellow 3. 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, 210Pb and 13.Cs, chronology, lacustrine sediments, climatic event, Co Ngoin, central Tibetan Plateau.

Holocene grassland vegetation, climate and human impact in central eastern Inner Mongolia

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science china Earth sciences 2005年第7期48卷 1025-1039页

作者： HUANG Fei1, Kealhofer Lisa2, XIONG shangfa3.& HUANG Fengbao1 1. nanjing institute of Geology and Paleontology,chinese {3. of sciences,nanjing 210008,china 2. Anthropology and sociology Department,santa Clara University,CA 95053.UsA 3. institute of Geology and Geophysics,chinese {3. of sciences,Beijing 100029,china nanjing institute of Geology and Paleontology Chinese Academy of Sciences Nanjing 210008 China Anthropology and sociology Department Santa Clara University CA 95053 United States institute of Geology and Geoohysics Chinese Academy of Sciences Beijina 100029 China

Phytolith and pollen preserved in the Taipusi Banner paleosol profile, central eastern Inner Mongolia, provide evidence of Holocene grassland vegetation, climate and human impact. The combined phytolith and pollen records reveal a major change in vegetation composition about 5000 a BP. Before 5000 a BP, the vegetation was dominated by Aneurolepidium chinese-stipa grandis grassland of C4 grasses. After 5000 a BP, C4 grasses rapidly retreated, indicating a shift to colder and more arid conditions. The gradual invasion of stipa krylovii, Ag-ropyron desertorum, Ephedra, Chenopodiaceae and Caragana reveal the onset of grassland degeneration. Between 10000 and 8720 a BP, the Aneurolepidium chinese-stipa grandis grassland included a small proportion of Artemisia shrub and Echionopos type plants, implying a strong winter monsoon and very weak summer monsoon. From 8720 to 7000 a BP, C4 grasses were common, indicating a strengthening of the summer monsoon. Between 7000 and 5000 a BP, the Holocene thermal maximum was evident, with a significant expansion of C4 grasses and the presence of some trees (such as Pinus and Betula, and so on) in or near the study site. From 4200?000 a BP, a sandy grassland of Artemisia and Agropyron desertorum together with Aster-type taxa occurred. Precipitation amelioration took place between 3.00 and 2170 a BP, with a rapid development of Echinops type plants and a small expansion of C4 grasses. From 2170 a BP to present, human activities accelerated the process of grassland degeneration.

关键词： phytolith and pollen records grassland environment change human impact Holocene central eastern Inner Mongolia.

Effects of chlorothalonil and carbendazim on nitrification and denitrification in soils

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Journal of Environmental sciences 2009年第4期21卷 458-467页

作者： LANG Man, CAI Zucong state Key Laboratory of soil and sustainable Agriculture, institute of soil science, {3. academy of sciences,nanjing 210008, china [a]state Key Laboratory of soil and sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 China

The effects of chlorothalonil and carbendazim on nitrification and denitrification in six soils in upland and rice paddy environments were investigated. Laboratory aerobic （60% water holding capacity） and anaerobic （flooded） conditions were studied at 25℃ and fungicide addition rates of 5.5 mg/kg A. I. （field rate, FR）, 20 times （20FR） and 40 times （40FR） field rate, respectively. The results indicated that chlorothalonil at the field rate had a slight inhibitory effect on one soil only, and that soil did not nitrify much in the first place. But chlorothalonil at higher rates inhibited nitrification significantly in all soils. For soils JXP and JXU with a pH of less than 5.0, chlorothalonil almost completely stopped their nitrification at 20FR and 40FR during the whole 14 d incubation period. For soils HNP and HNU with a pH of greater than 8.0, chlorothalonil also significantly inhibit nitrification at 20FR and 40FR （p 〈 0.05）. However, NH4＋ that was added to the soil was also almost completely nitrified by the end of the incubation period in these two soils. The effects of chlorothalonil at 20FR and 40FR on the nitrification of JsP and JsU soils, with a pH of 5.4 and 7.2, respectively, were intermediate between the other soil types. Chlorothalonil had no effect on denitrification at the field rate and had little effect at the higher rates of application in some soils. Carbendazim had essentially no effect on nitrification and denitrification in soils assessed.

关键词： fungicide nitrification denitrification chlorothalonil carbendazim

Two possible mechanisms for vortex self-organization

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science china Earth sciences 2006年第2期49卷 202-211页

作者： LUO Zhexian2, ZHOU Xiuji1 & GAO shouting3.1. chinese academy of Meteorological sciences, Beijing 100081, china 2. Department of space Information science, {3. University of Information science and Technology, {3. 210044, china 3. institute of Atmospheric Physics, chinese academy of sciences, Beijing 100029, china 2. Department of Environmental science Nanjing University of Information Science and Technology Nanjing 210044 China 1. chinese academy of Meteorological sciences Beijing 100081 China 3. institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

The vortex self-organization is investigated in this paper by four groups of numerical experiments within the framework of quasi-geostrophic model, and based on the experimental results two types of possible mechanisms for vortex self-organization are suggested. The meso-scale to-pography may enable separated vortices to merge into a larger scale vortex; and the interaction of meso-γ and meso-β scale systems may make separated vortices to self organize a typhoon-like vor-tex circulation.

关键词： vortex, self-organization, meso-scale topography, interaction of different scales.

Quantitative Relationship Between Land Use and Phosphorus Discharge in subtropical Hilly Regions of china

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Pedosphere 2003年第1期13卷 67-74页

作者： YANG JINLING and ZHANG GANLINinstitute of soil science, the chinese {3. of sciences, nanjing 210008 (china) institute of soil science the Chinese Academy of Sciences Nanjing 210008 (China)

The increase of phosphorus concentration is a crucial factor causing the eutrophication of water body,while land use has an important impact on agricultural non-point sources (NPs) phosphorus discharge. sevensites controlling the water in four sub-watersheds and the main exit of the Meicun Watershed of XuanchengCounty, Anhui Province, were investigated by dynamic monitoring of stream water and nutrient discharge,integrating interpretation of aerial image and GIs analysis to find out how the land use affects phosphorusloss with stream water in typical agriculture-forest watershed in subtropical china. These monitored sitesare different in structure of land use. Phosphorus concentration of the stream water was analyzed everyweek and at the next day of rainfall. The velocity of flow was measured by kinemometer to calculatethe runoff flux and phosphorus discharge. The results showed that the runoff flux and the discharges ofdissolved phosphorus (DP), particle-associated phosphorus (PAP) and total phosphorus (TP) had significantexponential relationships with the area percentages of forest, pond and paddy field. There existed a significantlinear relationship between the TP and PAP concentrations in stream water and the area percentages of forest,pond and paddy field, and the discharge of PAP was also significantly linearly correlated with the dischargeof suspended soil particles. There was a logarithmic linear relationship between DP and PAP discharges. Thestudy indicated that the adjustment of land use patterns and construction of ecologically sound landscapewould be an important measure to reduce the runoff discharge of phosphorus. The results would be veryuseful in building the best management practices (BMPs) of agricultural watershed in subtropics.

关键词： land use phosphorus runoff watershed

The reconstruction and interpretations of lake status at 6 ka and 18 ka *** inland mainland Asia

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chinese science Bulletin 1998年第14期43卷 1145-1157页

作者： QIN Boqiang 1, sHI Yafeng 1 and YU Ge 2, 3.1. nanjing institute of Geography & Limnology, chinese {3. of sciences, nanjing 210008, china 2. Dynamic Palaeoclimatology, Lund University, PO Box 117, s 221 00, Lund, sweden 3. Department of nanjing institute of Geography & Limnolagy Chinese Academy of Sciences Nanjing China Dynamic Palaeoclimatology Lund University Lund Sweden Department of Geology and Ocean sciences Nanjing University Nanjing China

By means of survey of literature through compilations of sedimentological, biogeological and geomorphologic data, the inland lake level changes in arid or semi arid mainland Asia at 6 and 18 ka B.P. have been reconstructed. The results showed that the lakes from western and northwestern Asia were characterized by very high water levels at 18 ka B.P., but low or intermediate water stands at 6 ka B.P. The high lake level in this region was associated with the southward displacement of westerlies, therefore, the extent of the high lake stand indicated the southern flank of westerlies during the glaciation. Conversely, the lakes from the eastern and southern Asia registered comparative low levels at 18 ka B.P. and significantly high one at 6 ka B.P. The lowering of lake level at 18 ka B.P. was caused by the weakened summer monsoon and the high lake level at 6 ka B.P. by the enhanced summer monsoon induced by the enlarged thermal contrast between land and ocean. The extent of high lake levels indicated the northern boundary of monsoon expansion. Between the above two regions, there is a climatic transitional zone in the Central Asia where the lake behavior was close to that in southeastern Asia at 6 ka B.P. but became similar to that in northwestern Asia at 18 ka B.P. Thus this zone became a transitional sector from the monsoon to the westerlies.

关键词： lake status inland mainland Asia westerlies monsoon.