Distributions and temperature dependence of branched glycerol dialkyl glycerol tetraethers in recent lacustrine sediments from China and Nepal
Distributions and temperature dependence of branched glycerol dialkyl glycerol tetraethers in recent lacustrine sediments from China and Nepal
复制标题
中国和尼泊尔近期湖泊沉积物中支链甘油二烷基甘油四醚的分布和温度依赖性。
DOI：
10.1029/2010jg001365
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发表时间：
2011-01-27
影响因子：
3.7
通讯作者：
Lue, Houyuan
中科院分区：
文献类型：
--
作者：
Sun, Qing;Chu, Guoqiang;Lue, Houyuan
对中国和尼泊尔24个湖泊表层沉积物中的甘油二烷基甘油四醚膜脂进行了分析。结果表明，支化GDGT类脂广泛存在于所研究的湖泊沉积物中。分枝GDGT在中国土壤中的分布差异(2007b)和中国湖泊沉积物表明，湖泊沉积物中的分枝GDGT是异地分枝GDGT和原地分枝GDGT的混合体。我们的结果支持温度是影响GDGT分布的主要因素的说法。季节性、来源和降雨量增加了支链四醚甲基化指数(MBT)/支链四醚环化率(CBT)替代物与温度之间相关性的不确定性。全球湖泊MBT/CBT指数与年平均气温的相关关系为：T=6.803-7.062 x CBT+37.090 x MBT(n=139p&t；0.0001，R-2=0.62，均方根温度=5.24℃)，对于pH值为8.5的全球湖泊，T=3.949-5.593 x CBT+38.213 x MBT(n=100，p<；0.0001，R2=0.73，均方根温度=4.27℃)。这种显著的相关性表明，MBT/CBT代用可能成为湖相环境中潜在的古温度代用。MBT/CBT替代物提供了一种独立的方法来评估和验证不同替代物对从湖泊沉积物中恢复古温度的敏感性。
Glycerol dialkyl glycerol tetraether (GDGT) membrane lipids in surface sediments from 24 lakes in China and Nepal were analyzed. The result shows that branched GDGT lipids occur widely in the studied lake sediments. The different distribution of branched GDGTs between the Chinese soils from Weijers et al. (2007b) and the Chinese lake sediments indicates that the branched GDGTs in the lacustrine sediment are the mixture of allochthonous and autochthonous branched GDGTs. Our result supports the suggestion that temperature is the principal factor affecting the distribution of GDGTs. Seasonality, sources, and precipitation increase the uncertainty of the correlation between the methylation index of branched tetraethers (MBT)/cyclization ratio of branched tetraethers (CBT) proxy and the temperature. The correlations of the MBT/CBT index with mean annual air temperature (T) for the global lakes are T = 6.803 - 7.062 x CBT + 37.090 x MBT (n = 139, p < 0.0001, R-2 = 0.62, and RMSE = 5.24 degrees C); for the global lakes with pH < 8.5, T = 3.949 - 5.593 x CBT + 38.213 x MBT (n = 100, p < 0.0001, R-2 = 0.73, and RMSE = 4.27 degrees C). The significant correlation suggests that the MBT/CBT proxy might be used as a potential paleotemperature proxy in the limnic environment. The MBT/CBT proxy provides an independent way to evaluate and verify the sensitivities of the different proxies for paleotemperature reconstruction from lacustrine sediments.