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| 1 | Climate as the dominant control on C_3 and C_4 plant abundance in the Loess Plateau: Organic carbon isotope evidence from the last glacial-interglacial loess-soil sequences显示文摘Abundance of C3 and C4 photosynthesis plants can be inferred relatively from stable carbon isotopic composi-tion of organic matter in soils. The samples from five sequences of the last glacial-interglacial loess-soil in the Chinese Loess Plateau have been measured for organic carbon isotopic ratios (d 13Corg). The organic carbon isotope data show that relative abundance (or biomass) of C4 plants was increased ca. 40% for each sampling site from the last glacial maximum (LGM) to Holocene optimum, and increased southeastward on the Loess Plateau during both periods of LGM and Holocene. Statistic analyses on the steady maximum d 13Corg values of Holocene soils and modern climatic data from the Loess Plateau and Inner Mongolia indicate that the C4 plant abundance increases with increasing temperature and decreasing precipitation. The C4 plant abundance is related much closer with mean April tem-perature and precipitation than annual. These results lead us to deduce following conclusions. First, temperature is the major factor for control on variations in C4 plant abundance in the Loess Plateau from the last glacial to interglacial. In the absence of favorable temperature condition, both of low moisture and low atmospheric CO2 concentration are insufficient to drive an expansion of the C4 plants in the plateau. Second, d 13Corg in the loess-paleosol sequences, as a proxy of the relative abundance of C4 plants in the Loess Plateau, could not be used as an indicator of changes in the summer monsoon intensity unless the tem-perature had changed without great amplitude. Since all C4 plants are grasses, finally, the increase of the C4 plants supports that forest has not been dominant in the ecosystem on the Loess Plateau during Holocene although precipitation and atmospheric CO2 were largely increased relative to those during LGM. | GU Zhaoyan, LIU Qiang, XU Bing, HAN Jiamao, YANG Shiling, DING Zhongli & LIU Tungsheng Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China Correspondence should be addressed to Gu Zhaoyan (e-mail: zgu@ 95777.com) | 2003 | Chinese Science Bulletin2003，48，12： | 14 |
| 2 | Pedogenic carbonate isotope record of vegetational evolution since late Miocene in Loess Plateau显示文摘lsotopic analyses for paleovegetational evolution have been carried out on samples of the pedogenic carbonate nodules in the Red Clay-Loess sequence at Lingtai (35°N), the Loess Plateau. Stable carbon isotopic composition indicates that ( ⅰ ) C4 plants might be present at least by7.0 Ma; ( ⅱ ) C4 plants expanded gradually between ~4.0 and ~3.2 Ma, and their biomass fraction was up to 50%; and ( ⅲ ) the biomass of C4 vegetation since ~2.0 Ma seems to have been decreased to the level (about 20%) before 4.0 Ma. C4 plant expansion at Lingtai cannot be fully understood with the 'global C4 expansion' model because it occurred much later up to 3.0 Ma than in Pakistan, which indicates that some changes in the regional climatic system may also contribute to C3/C4 shift except changes in atmospheric CO2 concentrations and temperature. The latitudinal zone for C3/C4 transition seems to move southwards slightly in East Asia, compared with the case in North America where 37°N is the ideal | Shiling Yang Zhongli Ding Zhaoyan Gu Jimin Sun Shangfa Xiong | 1999 | Chinese Science Bulletin1999，44，11： | 6 |
| 3 | ^(10)Be in quartz gravel from the Gobi Desert and evolutionary history of alluvial sedimentation in the Ejina Basin,Inner Mongolia,China显示文摘Reconstructing the evolutionary history of the Gobi deserts developed from alluvial sediments in arid regions has great significance in unraveling changes in both tectonic activity and climate.However,such work is limited by a lack of suitable dating material preserved in the Gobi Desert,but cosmogenic 10Be has great potential to date the Gobi deserts.In the present study,10Be in quartz gravel from the Gobi deserts of the Ejina Basin in Inner Mongolia of China has been measured to assess exposure ages.Results show that the Gobi Desert in the northern margin of the basin developed 420 ka ago,whereas the Gobi Desert that developed from alluvial plains in the Heihe River drainage basin came about during the last 190 ka.The latter developed gradually northward and eastward to modern terminal lakes of the river.These temporal and spatial variations in the Gobi deserts are a consequence of alluvial processes influenced by Tibetan Plateau uplift and tectonic activities within the Ejina Basin.Possible episodes of Gobi Desert development within the last 420 ka indicate that the advance/retreat of alpine glaciers during glacial/interglacial cycles might have been the dominant factor to influencing the alluvial intensity and water volume in the basin.Intense floods and large water volumes would mainly occur during the short deglacial periods. | LU YanWu GU ZhaoYan ALDAHAN Ala ZHANG HuCai POSSNERT Goran LEI GuoLiang | 2010 | Chinese Science Bulletin2010，55，33： | 6 |
| 4 | Diet control on carbon isotopic composition of land snail shell carbonate显示文摘Carbon isotope compositions for both the carbonate shells and soft bodies (organic tissue) of living land snails collected mostly from the Loess Plateau, China have been measured. The result shows that δ 13C values range from -13.1‰ to -4.3‰ for the aragonite shell samples and from -26.8‰ to -18.0‰ for the soft body samples. Although the shells are enriched in 13C relative to the bodies averagely by 14.2(±0.8)‰, the shell δ 13Ca values are closely correlated to the body δ 13Corg values, expressed as δ 13Ca = 1.021 δ 13Corg + 14.38 (R = 0.965; N = 31). This relationship indicates that δ 13Ca is primarily a function of the isotopic composition of the snail diets since previous studies have proved that the snail body is the same as their food in carbon isotope composition. In other words, carbon isotope compo-sition of the carbonate shell can be used as a proxy to estimate the dietary 13C abundance of the land snails. The data also support that the 13C enrichment of the carbonate shells results mainly from the equilibrium fractionations between the metabolic CO2, HCO3-in the hemolymph and shell aragonite, and partially from kinetic fractionations when snail shells form during their activity. | LIU ZongXiu GU ZhaoYan WU NaiQin XU Bing | 2007 | Chinese Science Bulletin2007，52，3： | 5 |
| 5 | Carbon isotopic record from Upper Devonian carbonates at Dongcun in Guilin, southern China, supporting the world- wide pattern of carbon isotope excursions during Frasnian-Famennian transition显示文摘Two positive d 13C excursions are presented in records from the Frasnian-Famennian (F-F) marine carbon-ate sediments in Europe, America, Africa, and Australia, having been considered as a worldwide pattern, and attrib-uted to enhanced organic carbon burial during the F-F biological mass extinction. However, this worldwide pattern has not been revealed from the well-deposited Late Devonian sequences in southern China. In this paper, a detailed inves-tigation has been made on the Late Devonian section at Dongcun, Guilin, southern China to constrain perturbations in d 13C of carbonates in the F-F deposited sequence. The result from this section also indicates two positive d 13C ex-cursions during the F-F transition. The first excursion with an amplitude of 1.5 occurred at the bottom of linguiformis Zone, later than the early excursion existing in the Late rhe-nana Zone of the Late Devonian profiles in other continents, especially, in central Europe. This difference has been ex-pected to be a result as conodont Palmatolepis linguiformis occurred earlier in southern China than other sites. The second excursion with an amplitude of 2.1 is located at the F-F boundary, same as the records from other continents. This result strongly supports the view that two carbon iso-tope positive excursions during the F-F transition are com-mon in carbonate sediments, resulting from worldwide in-creases of organic carbon burial intensity. | XU Bing GU Zhaoyan LIU Qiang WANG Chengyuan LI Zhenliang | 2003 | Chinese Science Bulletin2003，48，12： | 2 |
| 6 | The trend and extent of heavy metal accumulation over last one hundred years in the Liaodong Bay,China显示文摘 | Xu Bing Yang Xiaobo Gu Zhaoyan | 2009 | Chemosphere2009，75，4： | 1 |
| 7 | Distribution of soil phytolith-occluded carbon in the Chinese Loess Plateau and its implications for silica-carbon cycles 显示文摘 | ZUO Xinxin LU Houyuan GU Zhaoyan | 2014 | Plant Soil2014，374，12： | 1 |
| 8 | Grey characteristics of microbanding of stalagmite in Shihua Cave, Beijing and its climatic signification(I)显示文摘 | Xiaoguang Qin Dongsheng Liu Ming Tan Tieying Li Jinpo Lü Zhaoyan Gu Houyuan Lü Zhongli Ding Zhengtang Guo Jiaqi Liu Gaozhong Nie | 1998 | Science in China Series D: Earth Sciences1998，，2： | 1 |
| 9 | Variability of snail growing season at the Chinese Loess Plateau during the last 75 ka显示文摘Knowledge of seasonal climate change is one of the key issues facing Quaternary paleoclimatic studies and estimating seasonal climate change is difficult,especially changes such as seasonal length on glacial-interglacial timescales.The stable isotope composition from seasonal land snail shells provides the potential to reveal seasonal climatic features.Two modern land snail species,cold-aridiphilous Pupilla aeoli and thermo-humidiphilous Punctum orphana,were collected from different climatic zones in 18 localities across the Chinese Loess Plateau,spanning 11 degrees of longitude and covering a range of 1000 km2.The duration of the snail growing season(temperature ≥10℃) was shorter(202 ± 6 d) in the eastern Loess Plateau compared with in the western Loess Plateau(162 ±7 d).The δ13C of P.aeoli shells was ?9.1‰ to ?4.7‰ and ?5.0‰ to 0.3‰ for δ18O.For P.orphana,the δ13C ranged from ?9.1‰ to ?1.9‰ and ?8.9‰ to ?2.9‰ for δ18O.Both the δ13C and δ18O differences between the two snail species were reduced from the east to the western Loess Plateau(2.8‰ to 0.2 ± 1.1‰ for δ13C and 4.7‰ to 2.9 ± 1.3‰ for δ18O).These isotopic differences roughly reflect the difference in the growing season lengths between the east and west Loess Plateau indicating that the duration of the snail growing season shortens by 15 d or 19 d if the difference decreases by 1‰ in δ13C or δ18O,respectively.Thus,the difference in δ13C and δ18O between both snail species can be used to reveal the length of the snail growing season in the past.Based on our investigation,the length of the snail growing seasons from the Xifeng region during the last 75 ka was reconstructed.During the mid-Holocene(8-3 ka),the mean isotopic difference from both snail species reached maximum values of 2.6 ± 0.7‰ and 2.1 ± 1.4‰ for δ13C and δ18O,respectively.This was followed by MIS 3 that ranged from 2.5 ± 0.4‰ for δ13C and 1.6 ± 0.8‰ for δ18O.The Last Glacial Maximum changed by only 0.2‰ and 0.4‰ for δ13C and δ18O,respectively.Therefore,we estimate that the duration of the snail growing seasons to be ~200 ± 10 d during the mid-Holocene,190 ± 6 d in MIS 3 and 160 ± 3 d during the last glacial period. | HUANG LinPei WU NaiQin GU ZhaoYan CHEN XiaoYun | 2012 | Chinese Science Bulletin2012，57，9： | 1 |
| 10 | Distribution of soil phytolith-occluded carbon in the Chinese Loess Plateau and its implications for silica–carbon cycles显示文摘 | XinXin Zuo HouYuan Lu ZhaoYan Gu | 2014 | 2014 (1-2)2014，，1： | 1 |
| 11 | Grey characteristics of microbanding of stalagmite in Shihua Cave, Beijing and its climatic signification(I)显示文摘 | Xiaoguang Qin Dongsheng Liu Ming Tan Tieying Li Jinpo Lü Zhaoyan Gu Houyuan Lü Zhongli Ding Zhengtang Guo Jiaqi Liu Gaozhong Nie | 1998 | Science in China Series D: Earth Sciences1998，，2： | 1 |
| 12 | Grey characteristics of microbanding of stalagmite in Shihua Cave, Beijing and its climatic signification(I)显示文摘 | Xiaoguang Qin Dongsheng Liu Ming Tan Tieying Li Jinpo Lü Zhaoyan Gu Houyuan Lü Zhongli Ding Zhengtang Guo Jiaqi Liu Gaozhong Nie | 1998 | Science in China Series D: Earth Sciences1998，，2： | 1 |
| 13 | The trend and ex tent of heavy metal accumulation over last one hundred years in the Liaodong Bay, China 显示文摘 | Bing Xu Xiaobo Yang Zhaoyan Gu | 2009 | Chemosphere2009，，75： | 1 |
| 14 | Effect of aging on islet beta-cell function and its mechanisms in Wistar rats显示文摘 | Zhaoyan Gu Yingzhen Du Yu Liu Lichao Ma Lin Li Yanping Gong Hui Tian Chunlin Li | 2012 | AGE2012，，6： | 1 |
| 15 | The trend and extentof heavy metal accumulation over last one hundred years in theLiaodong Bay,China显示文摘 | XU Bing YANG Xiaobo GU Zhaoyan | 2009 | Chemosphere2009，75，4： | 1 |
| 16 | Distribution of carbon isotope composition of modern soils on the Qinghai - Tibetan Plateau 显示文摘 | Lu Houyuan Wu Naiqin Gu Zhaoyan | 2004 | Biogeochemistry2004，70，2： | 1 |
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