Applicability and calibration of the TEX86 paleothermometer in lakes
Applicability and calibration of the TEX86 paleothermometer in lakes
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DOI：
10.1016/j.orggeochem.2009.11.009
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发表时间：
2010-04-01
影响因子：
3
通讯作者：
Schouten, Stefan
中科院分区：
文献类型：
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作者：
Powers, Lindsay;Werne, Josef P.;Schouten, Stefan
我们对湖泊沉积物中的古甘油二烷基甘油四醚(GDGT)类脂进行了全球调查，以开发应用于大陆体系的TEX86古温指标。对全球分布的46个湖泊的表层沉积物进行了GDGT分析，但在所分析的46个湖泊中，只有20个湖泊明确地检测到了来自水生新古生物的异戊二烯GDGT。水生裂隙考古GDGT主要在大型湖泊(>；4000 km(2))和热液湖泊或火山湖的沉积物中检测到，这表明在一些(主要是较小的)湖泊中，要么水生裂隙考古动物群的丰度较低，导致沉积脂肪低于检测水平，要么它们不存在，被认为主要来自土壤细菌的分枝GDGT在所有被分析的湖泊沉积物中都被发现。为了减少土壤中类异戊二烯GDGT对TEX86湖温的影响，那些具有足够的古洞穴GDGT的湖泊的TEX86与年平均湖温有较好的相关性(r(2)=0.68，N=20)。我们应用了基于相对土壤输入(由BIT[分支和类异戊二烯四醚]指数确定)的过滤器，得到的校正关系为r(2)=0.86(N=12)，估计温度误差为3.6摄氏度。我们的结果表明，TEX86应该只应用于水生Crenarhorota产生足够GDGT的湖泊，而不是来自流域土壤或其他水生来源的类异戊二烯GDGT。(C)2009爱思唯尔有限公司。保留所有权利。
We have conducted a global survey of archaeal glycerol dialkyl glycerol tetraether (GDGT) lipids in lake sediments in order to develop the TEX86 paleotemperature proxy for application in continental systems Surface sediments of 46 globally distributed lakes were analyzed for GDGT, but isoprenold GDGT derived from aquatic Crenarchaeota, were only unambiguously detected in 20 of the 46 lakes analyzed. Aquatic crenarchaeotal GDGT were detected mainly in sediments from large lakes (>4000 km(2)) and hydrothermal or volcanic lakes, suggesting that in some (mostly smaller) lakes either aquatic Crenarchaeota are present at low abundance resulting in sedimentary lipids below levels of detection, or they are absent Branched GDGT, thought to be derived primarily from soil bacteria, were identified in all lake sediments analyzed. Correlation of the TEX86 in those lakes with sufficient amounts of putative crenarchaeotal GDGT with annual mean lake temperature is reasonably good (r(2) = 0.68, N = 20) In order to reduce the influence of soil derived isoprenoid GDGT on the TEX86 lake temperatures, we have applied a filter based on relative soil derived Inputs (as determined by the BIT [Branched and Isoprenoid Tetraether] index) which results in a calibration relationship with r(2) = 0 86 (N = 12) and an estimated temperature error of 3.6 degrees C Our results suggest that the TEX86 should be applied only in lakes with sufficient production of GDGT by aquatic Crenarchaeota relative to isoprenoid GDGT derived from soil in the watershed or other aquatic sources. (C) 2009 Elsevier Ltd. All rights reserved.