Co-variation of crenarchaeol and branched GDGTs in globally-distributed marine and freshwater sedimentary archives
Co-variation of crenarchaeol and branched GDGTs in globally-distributed marine and freshwater sedimentary archives
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DOI：
10.1016/j.gloplacha.2012.05.020
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发表时间：
2012-07
影响因子：
3.9
通讯作者：
S. Fietz;C. Huguet;J. Bendle;M. Escala;Christopher Gallacher;L. Herfort;R. A. Jamieson;A. Martínez-García
中科院分区：
文献类型：
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作者：
S. Fietz;C. Huguet;J. Bendle;M. Escala;Christopher Gallacher;L. Herfort;R. A. Jamieson;A. Martínez-García
甘油二烷基甘油四醚(GDGT)通常用于古生态和古气候重建中，主要有两种类型：异戊二烯和分枝GDGT。在水生环境中，最初认为异戊二烯类GDGT，特别是考古酚，主要来自水生古生物纲，而分枝GDGT是来自土壤细菌的异地输入。最近，在两个海洋沉积记录中描述了考古酚和分支GDGT的直接共变，这一观察表明，至少在某些水环境中，原位产生分支GDGT是可能的。在调查了来自全球19个不同地区的30组已发表和未发表的岩心和表层沉积物以及沉积物圈闭后，我们发现分支GDGT和石蜡考古酚的浓度之间普遍存在显著的相关性(p<；0.01；R2=0.57-0.99)，即使在与总有机碳(TOC)进行标准化时也是如此。这些数据集包括距离海岸不同的淡水和海洋环境，不同的氧化还原条件和不同的陆地物质输入路径。我们从这一大规模数据集的发现表明，这两种GDGT类型的共同或混合来源实际上在湖泊和海洋环境中是常见的。
Two major types of glycerol dialkyl glycerol tetraethers (GDGTs) are commonly used in paleoecological and paleoclimatological reconstructions: isoprenoidal and branched GDGTs. In aquatic environments, it was originally assumed that isoprenoidal GDGTs, especially crenarchaeol, derive mainly from aquatic Thaumarchaeota, while branched GDGTs are an allochthonous input derived from soil Bacteria. Recently, direct co-variation of crenarchaeol and branched GDGTs has been described in two marine sedimentary records, and this observation suggests that in situ production of branched GDGTs is possible at least in some aquatic environments. After investigating 30 published and unpublished data sets from downcore and surface sediments as well as sediment traps from 19 distinct regions around the world, we found a widespread significant correlation between concentrations of branched GDGTs and crenarchaeol (p<0.01; r2=0.57–0.99), even when normalized against TOC, where available. These data sets include freshwater and marine environments with varying distances from the shore, varying redox conditions and different terrestrial matter input pathways. Our findings from this large-scale data set suggest that a common or mixed source for both GDGT types is actually commonplace in lacustrine and marine settings.