Lignin biomarker and isotopic records of paleovegetation and climate changes from Lake Erhai, southwest China, since 18.5kaBP
Lignin biomarker and isotopic records of paleovegetation and climate changes from Lake Erhai, southwest China, since 18.5kaBP
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DOI：
10.1016/j.quaint.2010.04.014
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发表时间：
2011
影响因子：
2.2
通讯作者：
S. Tareq;H. Kitagawa;K. Ohta
中科院分区：
文献类型：
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作者：
S. Tareq;H. Kitagawa;K. Ohta
对古植被的深入了解对于更好地了解过去的气候变化至关重要，并为改进对未来气候变化的预测提供必要的背景。在本研究中，测定了洱海（北纬25°50′；东经100°10′，中国西南部）沉积有机质（SOM）的稳定同位素（δ13C和δ15N）和木质素生物标志物，以重建古植被并寻找植被与气候的关系。稳定碳同位素特征表明，自18.5kaBP以来的沉积期有机质主要来源于C3植物。碳（δ13C：-28.8至-23.9‰）和氮（δ15N：1.2-4.1‰）同位素值的变化可能与陆地径流（即降水）的变化有关。木质素的碱性CuO氧化产物的组成显示，全新世早期，湖泊流域的陆地植被从富含裸子植物到富含被子植物植物发生了显着变化。木质素酚植被指数（LPVI）也表明了陆地植被的变化，在过去的 18.5ka 中几乎没有更细微的变化，作为陆地植被整体特征的单一代表。与过去的亚洲季风记录（东阁洞石笋δ18O记录）相比，LPVI表明植被变化与亚洲季风变率之间存在直接联系，可能受到全球气候变化的影响。
A sound knowledge of paleovegetation is fundamental to better understanding of past climate variability, and provides necessary background for improving predictions of future climate changes. In the present study, stable isotopes (δ13C and δ15N) and lignin biomarker of sedimentary organic matter (SOM) from Lake Erhai (25°50′ N; 100°10′ E, Southwest China) were determined to reconstruct paleovegetation and to find vegetation–climate relationships. The stable carbon isotope signatures suggested that the organic matter mostly derived from C3 plants throughout the depositional periods since 18.5kaBP. The variability of isotopic values of carbon (δ13C: −28.8 to −23.9‰) and nitrogen (δ15N: 1.2–4.1‰) might be related to changes in terrestrial runoff (i.e., precipitation). Compositions of the alkaline CuO-oxidation products of lignin showed a significant change in terrestrial vegetation from gymnosperm-rich to angiosperm-rich plants at lake catchments in the early-Holocene. The lignin phenol vegetation index (LPVI) also indicated changes in terrestrial vegetation with few more subtle changes during the last 18.5ka as a single proxy of entire characteristic of terrestrial vegetation. In comparison to past Asian monsoon records (δ18O record in Stalagmite of Dongge cave), LPVI suggested a direct linkage between vegetation changes and Asian monsoon variability that might be influenced by global climate changes.