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CPI values of terrestrial higher plant-derived long-chain n-alkanes: a potential paleoclimatic proxy
Zhiguo Rao Zhaoyu Zhu Suping Wang Guodong Jia Mingrui Qiang Yi Wu 《Frontiers of Earth Science》2009,3(3):266-272
Carbon Preference Index (CPI values) of higher plant-derived long-chain n-alkanes extracted from 62 surface soil samples in eastern China exhibited a specific pattern of variations, namely gradual
increase with the increasing latitudes. Such regular variations existed in both forest soil and grassland soil. Our data implied
that CPI values of higher plant-derived long-chain n-alkanes had a certain connection with climatic conditions, and such a connection was not influenced by vegetation types.
Together with previous data from marine sediments, loess/paleosol sequences, tertiary red clay and modern plants, our observation
made us conclude that CPI values of higher plant-derived long-chain n-alkanes may be used as an excellent proxy for paleoclimatic studies. 相似文献
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Use of biomarkers indices in a sediment core to evaluate potential pollution sources in a subtropical reservoir in Brazil 总被引：1，自引：0，他引：1
The presence of PAHs, n-alkanes, pristane, and phytanes in core sediment from the Vossoroca reservoir (Parana, southern Brazil) was investigated. The total concentration of the 16 PAHs varied from 15.5 to 1646 μg kg−1. Naphthalene was present in all layers (3.34–74.0 μg kg−1). The most abundant and dominant n-alkanes were n-C15 and n-C36, with average concentrations of 198.1 ± 46.8 and 522.9 ± 167.7 μg kg−1, respectively. Lighter n-alkanes were distributed more evenly through the layers and showed less variation, specially n-C9, n-C12, and n-C18, with average concentrations of 14.6 ± 3.0, 31.6 ± 1.9, and 95.0 ± 5.2 μg kg−1, respectively; heavier n-alkanes were more unevenly distributed. 相似文献
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Latitudinal variations of CPI values of long-chain n-alkanes in surface soils:Evidence for CPI as a proxy of aridity 总被引：1，自引：0，他引：1
Carbon preference index (CPI) of long-chain n-alkanes preserved in surface soil increases gradually from southeastern China to the north margin of Loess Plateau.Along this latitudinal transect,the CPI value correlates to relative humidity,precipitation,and temperature with a negative linear relationship,respectively,whereas the correlation of CPI to temperature is relatively weak.In the Wuyi,Shennongjia,and Tianshan Mountains,CPI values do not change systemically with altitude increasing (or temperature decreasing).However,mean value of CPI for the individual mountain increases in turn from the humid mountain to the arid.These results jointly suggest that aridity (or humidity) is a dominate climate factor in altering soil CPI value.High CPI values of geological records therefore indicate the arid paleoclimate.Though long-chain n-alkanes in soil are derived mainly from leaf wax of terrestrial vascular plants,the regular latitudinal variations of soil CPI might not be caused by the change of vegetation.We speculate that increased long-chain n-alkanes from microbes and/or enhanced biodegradation in the humid climate lead to the decrease of soil CPI. 相似文献
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