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The implication of tree-rings δ^(13)C for interaction between the atmosphere and the biosphere

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chinese science Bulletin 1999年第S2期44卷 83-85页

作者： WANG Shilu, WAN Guojiang and AN Ning state key {2. of Environmental geochemistry, institute of geochemistry, chinese academy of sciences, guiyang 550002, china state key {2. of Environmental geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China

1 Background THE Ci/Ca, the ratio of intercellular and ambient C02.partial pressure, is internally controlled by thestomatal conductance and assimilation rate, and is externally affected by the atmospheric CO2.concent... 详细信息

1 Background THE Ci/Ca, the ratio of intercellular and ambient C02./sub> partial pressure, is internally controlled by thestomatal conductance and assimilation rate, and is externally affected by the atmospheric CO2./sub> concentration and climate changes. Ci/Ca can be only estimated by the isotopic fractionation equation of Farquchar. However, this method is limited by the very little observation of atmospheric δ13 C before1980. Leavitt had to interpolate the atmospheric δ13 C by means of the polynomial. A geochemicalmethod to model Ci/Ca by tree-ring δ13C has been developed to reduce the dependence. By the estimated tree-ring Ci/ Ca, the authors here discuss C02./sub> and water exchanges between the atmosphere and biosphere that greatly influence the climate

关键词： tree-rings δ13C carbon cycle water-use efficiency.

Experimental study on the interaction between peat,lignite and germanium-bearing solution at low temperature

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science china Earth sciences 2005年第9期48卷 1411-1417页

作者： QI Huawen1,2. HU Ruizhong1 & QI Liang1 1. key laboratory of {2. Deposit geochemistry, chinese academy of sciences, guiyang 550002, china 2. Department of Earth science, Nanjing University, Nanjing 2.0093, china key laboratory of {2. Deposit geochemistry Chinese Academy of Sciences Guiyang China Department of Earth science Nanjing University Nanjing Chin

The interaction between peat, lignite and germanium(Ge)-bearing solution with an initial Ge concentration of 5 mg/L was studied at 2.―100℃ and at pH 2.96―12.08. The results show that the apparent transfer ratios of peat and lignite for Ge in the solution were positively correlated with temperature in acid environment (initial pH=2.96), and the ratios (up to 86.5%) of lignite were obviously higher than those (up to 58.5%) of peat, but the organic transfer ratios of lignite were lower than those of peat. The activation energy values for interaction between peat, lignite and Ge-bearing solution are 30.96 and 15.67 kJmol?1, respectively. The strong acid (initial pH=2.96) and the strong alkaline (initial pH=12.08) environment contribute to the transfer of Ge in the solution. At 4

关键词： low temperature, peat, lignite, Ge4+, complexation.

Relationship between δ^(13)C and index of ring width

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chinese science Bulletin 1999年第S2期44卷 81-83页

1 Materials and methods THE tree-ring reported here is one of pine discs sampled at 3 2.0 m a.s.l. in Qongtelian Valley in the Tuomu’er Peak region in 1978. The local geographical and climate condition has been introduced in detail. An index series was obtained after the width of tree-rings on 5 different radii was measured andfitted by linear and negative exponential functional regression. Each annual ring has been separated on the whole to simultaneously measure △14 C and δ13 C of treerings. Cellulose was extracted by the standard chemical method, then oxidized by copper oxide to C02./sub>.Carbon isotopic analyses were performed with a Mat-2.2.mass spectrometer. Results are expressed in thestandard δ notation with respect to the PDB standard with a precision of 0.1‰. 2

关键词： tree rings δ13C index of ring width correlation climate changes.

Existing state of Cd in the Niujiaotang Cd-rich zinc deposit, Guizhou, china

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chinese science Bulletin 1999年第S2期44卷 182-185页

作者： YE Lin and LlU Tiegeng Open laboratory of ore Deposit {2., institute of geochemistry, chinese academy of sciences, guiyang 550002, china Open laboratory of ore Deposit {2. Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China

As a dispersed element, cadmium is difficult to enrich and mineralize. As the Cd tetrahedron is similar tothat of Zn in covalent radius and crystal structure, both the elements possess similar geochemical *** is present mainly as isomorphous impurity in sphalerite. So Cd, as an associated element, occurslargely in Pb-Zn deposits. Current research both at home and abroad is focused on the environmental effect of Cd, but little work has been done on the mechanism of enrichment and mineralization of Cd. Theresearch papers available are mostly restricted to the ordinary geochemical characteristics of CdFrom the end of 1980s to the early 1990s, independent ore deposits of Te, Tl and other dispersed elements were discovered in the region of Southwest china. Prof. Tu Guangzhr proposed that dispersed elements can form their independent ore deposits. It has been realized that the dispersed

关键词： Cd Niujiaotang Cd-rich zinc deposit Guizhou.

High resolution environmental records in recent sediments of Erhai Lake, Yunnan Province

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chinese science Bulletin 1999年第S2期44卷 88-90页

作者： CHEN Jingan, WAN Guojiang and TANG Degui state key {2. of Environmental geochemistry, institute of geochemistry, chinese academy of sciences, guiyang 550002, china state key {2. of Environmental geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China

IN the past half a century, the global paleoclimate has been successfully reconstructed by natural recordssuch as ice core, loess and deep-sea sediments. However, these works mostly focused on long-timescale climatic changes. Along with the appearance of modern environmental problems including globalwarming, people are increasingly concerned about short-term climatic variations (annual to century scale)within the historical period. Therefore, it is an urgent and significant task for scientists to obtain continuous and high resolution natural records so as to reconstruct recent climatic changes truly and predict theclimate in the near future. As a main lodging of surface substances, the plateau-lake sediment continuously records the information of regional climate and environment with annual to decade resolution. Undoubtedly it is one

关键词： lake sediments high resolution climatic changes Erhai Lake.

Relationship of soil surface CO_2.flux with microbial biomass carbon in the karst areas of Southwest china

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chinese science Bulletin 1999年第S2期44卷 122-123页

作者： PIAO Hechun, HONG Yetang and YUAN Zhiyun state key {2. of Environmental geochemistry, institute of geochemistry, chinese academy of sciences, guiyang 550002, china state key {2. of Environmental geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China

THE production of C02.in the soil results from the oxidation of soil organic matter by heterotrophic microorganisms and by the respiration of plant roots. The release of C02.from the soil is a major flux in theglobal ... 详细信息

THE production of C02./sub> in the soil results from the oxidation of soil organic matter by heterotrophic microorganisms and by the respiration of plant roots. The release of C02./sub> from the soil is a major flux in theglobal carbon cycle, which is largely fuelled by plant production. In this note, we investigated the release of C02./sub>from soils of the karst region. We measured the amount of soil microbial biomass carbon,soluble organic carbon in the soil, and the flux of C02./sub> from the soil surface over a 1-year period. Thisnote is to examine the factors affecting the flux of C02./sub> from the soil surface in an ecosystem with nutrientpoor soils and limited amounts of soil microbial biomass. This study was conducted from June 1997 through May 1998 on a hill side, located in the suburbs ofguiyang City in Guizhou Province of china （latitude 2.°30’N, longitude 106°39’E）. Situated 1

关键词： soil carbon dioxide karst areas.

Sulfur isotopic composition of Yellow and Yangtze rivers and uplift of the Qinghai-Xizang Plateau

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chinese science Bulletin 1999年第S2期44卷 120-122页

作者： HONG Yetang, GU Ailiang, WANG Hongwei and HONG Bing state key {2. of Environmental geochemistry, institute of geochemistry, chinese academy of sciences, guiyang 550002, china state key {2. of Environmental geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China

THE sulfur isotopic composition of dissolved sulfate in any rivers has been recognized as a mixture of thesulfur derived from the soil, bedrock and the atmosphere. The measurement of the sulfur isotopic composition in a river water can provide background information on the biogeochemical cycling of sulfur in theriver basin. So far, however, little work has been done on sulfur isotope in the watersheds of the majorrivers of the world. In particular, no information of the sulfur isotope of the major rivers in Asian conti-

关键词： sulfur isotopic composition Yellow and Yangtze rivers uplift Qinghai-Xizang Plateau.

PROGRESS OF SMCE CHEMISTRY RESEARCH IN china DURING 1995─1997

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空间科学学报 1998年第S1期18卷 21-26页

作者： WANG Shi-jie OUYANG Zi-yuan (state key Laboratorp of Environmental {2.,institute of geochemistry, The chinese academy of sciences, guiyang 550002)

Over the past years chinese space chemists have done much work on space chemistry and related disciplines, especially on the solar nebular evolution,meteorjtes, comparative planetology and the origin and evolution of ... 详细信息

关键词： Progress Space chemistry

Boron isotopic fractionation in laboratory inorganic carbonate precipitation:Evidence for the incorpora-tion of B(OH)_3 into carbonate

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science china Earth sciences 2008年第12期51卷 1776-1785页

作者： XIAO YingKai1,2, LI HuaLing1,3, LIU WeiGuo4, WANG XiuFang1 & JIANG ShaoYong5 1 Qinghai institute of Salt Lakes, chinese academy of sciences, Xining 810008, china 2 state key laboratory of Environmental geochemistry, institute of geochemistry, chinese academy of sciences, guiyang 550002, china 3 Nanjing institute of Geology and Mineral Resources, Nanjing 210016, china 4 state key laboratory of Loess and Quaternary Geology, institute of Earth Environment, chinese academy of sciences, Xi’an 710075, china 5 state key laboratory for Mineral deposits Research, Department of Earth sciences, Nanjing University, Nanjing 210093, china Qinghai institute of Salt Lakes Chinese Academy of Sciences Xining China state key {2. of Environmental geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang China Nanjing institute of Geology and Mineral Resources Nanjing China state key {2. of Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences Xi’an China state key {2. for Mineral deposits Research Department of Earth Sciences Nanjing University Nanjing China

A laboratory inorganic carbonate precipitation experiment at high pH of 8.96 to 9.34 was conducted, and the boron isotopic fractionations of the precipitated carbonate were measured. The data show that boron isotopic fractionation factors (αcarb-3) between carbonate and B(OH)3 in seawater range 0.937 and 0.965, with an average value of 0.953. Our results together with those reported by Sanyal and collabo-rators show that the αcarb-3 values between carbonate and B(OH)3 in solution are not constant but are negatively correlated with the pH of seawater. The measured boron isotopic compositions of carbonate precipitation (δ11Bcarb) do not exactly lie on the best-fit theoretical δ 11B4-pH curves and neither do they exactly parallel any theoretical δ 11B4-pH curves. Therefore, it is reasonable to argue that a changeable proportion of B(OH)3 with pH of seawater should also be incorporated into carbonate except for the dominant incorporation of B(OH)4- in carbonate . Hence, in the reconstruction of the paleo-pH of sea-water from boron isotopes in marine biogenic carbonates, the use of theoretical boron isotopic frac-tionation factor (α4-3) between B(OH)4- and B(OH)3 is not suitable. Instead, an empirical equation should be established.

关键词： boron isotopic fractionation biogenic carbonate B(OH)3 incorporation