Paleovegetation reconstruction using δ 13 C of Soil Organic Matter
Paleovegetation reconstruction using δ 13 C of Soil Organic Matter
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DOI：
10.5194/bg-5-1325-2008
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发表时间：
2008-09
期刊：
影响因子：
4.9
通讯作者：
Guoan Wang;X. Feng;Jiamao Han;Liping Zhou;W. Tan;F. Su
中科院分区：
文献类型：
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作者：
Guoan Wang;X. Feng;Jiamao Han;Liping Zhou;W. Tan;F. Su
抽象的。C_3和C_4植物对植被的相对贡献可以用土壤有机质的δ~（13）C来估算。这种方法具有很大的潜力，利用古土壤的古生态重建。然而，存在两个主要的不确定性，这限制了本申请的准确性。一个是δ 13 C富集，因为植物碳被并入土壤有机质。另一种是由于环境对植物δ 13 C的影响。为了缩小古植被重建的误差，收集了两类数据并进行了分析。首先，我们研究了华北地区557种C3和136种C4植物的δ 13 C沿降水梯度的变化。C3植物δ 13 C值与年降水量呈负相关，相关系数为-0.40 ‰/100mm，而C4植物δ 13 C值与年降水量的相关系数不显著。其次，测定了3个样点14个土壤剖面的有机质δ 13 C。植被与土壤有机质的同位素组成差异，表层土壤为1.8 ‰，底层土壤为2.8 ‰。通过对黄土高原中部全新世和末次冰期（LG）古植被的采样重建，得出如下结论：如果不对δ 13 C富集进行分解校正，C4丰度将被高估。还讨论了其它修正的重要性和不确定性。
Abstract. The relative contributions of C3 and C4 plants to vegetation at a given locality may be estimated by means of δ13C of soil organic matter. This approach holds a great potential for paleoecological reconstruction using paleosols. However, two main uncertainties exist, which limits the accuracy of this application. One is δ13C-enrichment as the plant carbon becomes incorporated into soil organic matter. The other is due to environmental influences on δ13C of plants. Two types of data were collected and analyzed with an objective of narrowing the error of paleovegetation reconstruction. First, we investigated δ13C variations of 557 C3 and 136 C4 plants along a precipitation gradient in North China. A strong negative correlation is found between the δ13C value of C3 plants averaged for each site and the annual precipitation with a coefficient of −0.40‰/100mm, while no significant coefficients were found for C4 plants. Second, we measured δ13C of soil organic matters for 14 soil profiles at three sites. The isotopic difference between vegetation and soil organic matter are evaluated to be 1.8‰ for the surface soil and 2.8‰ for the soil at the bottom of soil profiles. We conducted a sample reconstruction of paleovegetation at the central Chinese Loess Plateau during the Holocene and the Last Glacial (LG), and conclude that, without corrections for δ13C-enrichment by decomposition, the C4 abundance would be overestimated. The importance and uncertainties of other corrections are also discussed.