Temperature-dependent variation in the distribution of tetraether membrane lipids of marine Crenarchaeota: Implications for TEX86 paleothermometry
Temperature-dependent variation in the distribution of tetraether membrane lipids of marine Crenarchaeota: Implications for TEX86 paleothermometry
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DOI：
10.1029/2004pa001041
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发表时间：
2004-12
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影响因子：
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通讯作者：
C. Wuchter;Stefan Schouten;M. Coolen;J. Damsté
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文献类型：
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作者：
C. Wuchter;Stefan Schouten;M. Coolen;J. Damsté
[1]最近，一种新的地球化学温度代用指标TEX 86被引入。这个代理是基于环戊烷部分的甘油二烷基甘油四醚（GDGT）的海洋Crenarchaeota的膜脂，它的变化作为对温度的响应的数量。然而，到目前为止，只有沉积物数据被用来建立这一代理，实验工作是缺失的。我们用海洋泉古菌在5至35°C的温度和27和35‰的盐度下进行了围隔生态系统研究，以测试TEX 86代用品的有效性。海洋泉古菌在这些围隔中的生长是明显的，从海洋泉古菌膜脂的浓度大幅增加，量高达3400纳克/升。随着温度的升高，观察到在crenarchaeotal膜脂质的环戊烷部分的数量增加。不同盐度对GDGT的分布没有影响。TEX 86与培养温度呈显著的线性关系：TEX 86 = 0.015 × T + 0.10（r2 = 0.79）。该方程与从岩心顶部获得的相关性具有相似的斜率，但在交点处不同（TEX 86 = 0.015 × T + 0.28，r2 = 0.92）。这种差异主要是由与岩心顶部样品相比，在孵育系列中crenarchaeol的区域异构体的量较少决定的。这些孵育实验表明，水温确实是海洋Crenarchaeota的膜分布的主要控制因素，并证实了TEX 86代理依赖于生理反应来调节膜流动性。
[1] Recently, a new geochemical temperature proxy, the TEX86, was introduced. This proxy is based on the number of cyclopentane moieties in the glycerol dialkyl glycerol tetraethers (GDGTs) of the membrane lipids of marine Crenarchaeota, which changes as a response to temperature. However, until now, only sediment data have been used to establish this proxy, and experimental work is missing. We performed mesocosm studies with marine Crenarchaeota incubated at temperatures ranging from 5 to 35°C and salinities of 27 and 35‰ to test the validity of the TEX86 proxy. Growth of marine Crenarchaeota in these mesocosms was evident from the substantial increase in the concentration of marine Crenarchaeotal membrane lipids with amounts up to 3400 ng/L. With increasing temperature, an increase in the number of cyclopentane moieties in the crenarchaeotal membrane lipids was observed. Different salinities did not show any effect on the GDGT distribution. The TEX86 showed a significant linear correlation to incubation temperature: TEX86 = 0.015 × T + 0.10 (r2 = 0.79). This equation has a similar slope to the correlation obtained from core tops but differs in the intersection (TEX86 = 0.015 × T + 0.28, r2 = 0.92). This difference is mainly determined by the smaller amount of the regioisomer of crenarchaeol in the incubation series compared to core top samples. These incubation experiments indicates that water temperature is indeed the major controlling factor for the membrane distribution of marine Crenarchaeota and confirms that the TEX86 proxy depends on a physiological response to regulate membrane fluidity.