Tetraether biomarker records from a loess-paleosol sequence in the western Chinese Loess Plateau.
Tetraether biomarker records from a loess-paleosol sequence in the western Chinese Loess Plateau.
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DOI：
10.3389/fmicb.2013.00199
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发表时间：
2013
影响因子：
5.2
通讯作者：
Chen F
中科院分区：
文献类型：
--
作者：
Jia G;Rao Z;Zhang J;Li Z;Chen F
土壤中普遍存在的甘油二烷基甘油四醚（GDGT）及其记录温度和环境变化的能力，为利用黄土高原黄土-古土壤序列（LPS）独立重建大陆古温度和古环境提供了前景。在这项研究中，我们提出的GDGT派生代理记录的最后70 kyr从元宝LPS，西部CLP。由支链四醚环化和甲基化指数（MBT-CBT）重建的温度记录显示，距今约20 kyr的冰消期变暖开始于距今约15 kyr的夏季风加强之前，这与CLP东南部的MBT-CBT温度记录在时间上是一致的。冰消期最大升温约为10°C，略高于CLP东南部，这可能是由于研究地点纬度较高，内陆较远。支化和类异戊二烯四醚（BIT）指数在冰川黄土中显示出较高的值（范围为0.87-0.96，平均值为0.93），在全新世古土壤中显示出较低的值（范围为0.76-0.91，平均值为0.83），自全新世早期以来呈稳定下降趋势。这种下降趋势可能表明，自全新世早期以来，Thaumarchaeota相对于GDGT生产细菌的活性增强，但其他可能性，如类异戊二烯GDGT的优先降解或古土壤剖面中活古细菌相对于细菌的向上增加，不能完全排除。因此，我们的研究结果表明，需要进一步研究土壤中微生物群落结构和GDGT分子的差异降解。
The ubiquitous occurrence of glycerol dialkyl glycerol tetraethers (GDGTs) in soils and their ability to record temperature and environmental changes offer the prospect of independently reconstructing continental paleotemperature and paleoenvironment from the loess-paleosol sequences (LPS) from the Chinese Loess Plateau (CLP). In this study we present records of GDGT-derived proxies for the last 70 kyr from the Yuanbao LPS, western CLP. Temperature record reconstructed from the cyclization and methylation index of branched tetraethers (MBT-CBT) displays that the onset of deglacial warming at ~20 kyr before present (BP) precedes the strengthening of summer monsoon at ~15 kyr BP, which is in agreement in timing with previous MBT-CBT temperature records from the southeastern CLP. The maximal deglacial warming of ~10°C is slightly higher than those in the southeastern CLP, perhaps due to the higher latitude and farther inland of the study site. The Branched and Isoprenoid Tetraether (BIT) index shows higher values (0.87–0.96 range, 0.93 average) in the glacial loess and lower values (0.76–0.91 range, 0.83 average) in the Holocene paleosols, with a steady decreasing trend since the early Holocene. The decreasing trend could suggest enhanced Thaumarchaeota relative to GDGT producing bacteria activity since the early Holocene, but other possibilities, such as preferential degradation of isoprenoid GDGTs or upward increase in living archaea relative to bacteria in the paleosol profile, cannot be fully excluded. Our results thus demonstrate the need of future study on microbial community structure in soil column and differential degradation of GDGT molecules.
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影响因子：
3
作者：
Powers, Lindsay;Werne, Josef P.;Schouten, Stefan
通讯作者：
Schouten, Stefan
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作者：
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