کد مقاله کد نشریه سال انتشار مقاله انگلیسی ترجمه فارسی نسخه تمام متن
5161472 1502258 2017 31 صفحه PDF سفارش دهید دانلود رایگان
عنوان انگلیسی مقاله ISI
Impact of early diagenesis on distributions of Sphagnum n-alkanes in peatlands of the monsoon region of China
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موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
Impact of early diagenesis on distributions of Sphagnum n-alkanes in peatlands of the monsoon region of China
چکیده انگلیسی
Sphagnum species are important peat-forming plants in wetlands the world over. Their n-alkane distributions are typically characterized by a predominance of mid-chain (C23 and C25) alkanes, a property that has been employed in paleoclimatic reconstruction based on peat sequences. However, knowledge of the fate of Sphagnum-derived n-alkanes during the very early stage of diagenesis remains limited. This study compares the n-alkane differences between samples of fresh plants and litter collected from four peatlands across the monsoon region of China. The results clearly show that the distributions of Sphagnum-derived n-alkanes differ between the plants and the litter, with proportional decreases in C23 and C25n-alkanes and increases in C29 and C31 homologs in the litter. Other than the influence of species shifts, changes in the n-alkane distributions between the fresh plants and litter samples may be caused by preferential degradation of mid-chain n-alkanes (C23 and C25) relative to their longer chain homologues (C29 and C31) during the early diagenesis of Sphagnum n-alkanes. This hypothesis is supported by decreases in CPI values and positive excursions of δ13C values of C23 and C29n-alkanes from the plant to the litter samples. Regardless of what the exact mechanisms for the changes may be, the Paq ratio should be applied with caution as a paleoclimatic proxy in peat deposits, especially those located in warmer climates or deposited during former warmer stages. Relatively low Paq values may result from elevated microbial degradation of Sphagnum-alkanes in such conditions and hence fail to record the former plant assemblages accurately.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Organic Geochemistry - Volume 105, March 2017, Pages 13-19
نویسندگان
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