Ancient DNA derived from alkenone-biosynthesizing haptophytes and other algae in Holocene sediments from the Black Sea
Ancient DNA derived from alkenone-biosynthesizing haptophytes and other algae in Holocene sediments from the Black Sea
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DOI：
10.1029/2005pa001188
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发表时间：
2006-02-18
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影响因子：
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通讯作者：
Damsté, JSS
中科院分区：
文献类型：
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作者：
Coolen, MJL;Boere, A;Damsté, JSS
[1]全新世海表面温度（SST）的黑海已重建使用沉积的C-37不饱和烯酮假定来自球石藻类附着体Emiliania huxleyi，其化石球石是一个重要组成部分的单元I沉积物。然而，烯酮也可以由不产生显微可识别的球孢子的附着菌物种生物合成。在这种基于U-37（K '）的过去SST重建中，附着植物的种特异性鉴定是重要的，因为不同的种具有不同的烯酮SST校准。结果表明，E.在黑海沉积中心（> 2000 m）3600年前的化石记录中，huxleyi仅占真核生物18 SrDNA总量的很小比例（小于0.8%）。主要的化石18 S rDNA来源于甲藻（Gymphocyaninium spp.），它们是现代黑海夏季浮游植物水华的主要成员。利用聚合酶链反应/变性梯度凝胶电泳方法，我们回收了大量的保存的458碱基对（bp）长的18 S rDNA片段的附着菌选择性。来自全新世黑海沉积物的huxleyi。没有检测到其他化石附着植物序列，表明E。赫胥黎烯酮-SST校准至少可以应用于最近的3600年。古老的E. huxleyi DNA受到很好的保护，防止降解，因为DNA/烯酮比率在整个沉积物芯中没有显著降低，20%的类似于2700年前的化石E.赫胥黎DNA的长度仍然高达23,000个碱基对。我们表明，化石DNA提供了巨大的潜力，研究全新世古生态和古环境的缺氧深海设置在前所未有的细节。
[1] Holocene sea surface temperatures (SST) of the Black Sea have been reconstructed using sedimentary C-37 unsaturated alkenones assumed to be derived from the coccolithophorid haptophyte Emiliania huxleyi, whose fossil coccoliths are an important constituent of the unit I sediments. However, alkenones can also be biosynthesized by haptophyte species that do not produce microscopic recognizable coccoliths. A species-specific identification of haptophytes is important in such U-37(K')-based past SST reconstructions since different species have different alkenone-SST calibrations. We showed that 18S rDNA of E. huxleyi made up only a very small percentage ( less than 0.8%) of the total eukaryotic 18S rDNA within the up to 3600-year-old fossil record obtained from the depocenter (> 2000 m) of the Black Sea. The predominant fossil 18S rDNA was derived from dinoflagellates ( Gymnodinium spp.), which are predominant members of the summer phytoplankton bloom in the modern Black Sea. Using a polymerase chain reaction/denaturing gradient gel electrophoresis method selective for haptophytes, we recovered substantial numbers of a preserved 458-base-pair (bp)-long 18S rDNA fragment of E. huxleyi from the Holocene Black Sea sediments. Additional fossil haptophyte sequences were not detected, indicating that the E. huxleyi alkenone-SST calibration can be applied for at least the last similar to 3600 years. The ancient E. huxleyi DNA was well protected against degradation since the DNA/alkenone ratio did not significantly decrease throughout the whole sediment core and 20% of similar to 2700-year-old fossil E. huxleyi DNA was still up to 23,000 base pairs long. We showed that fossil DNA offers great potential to study the Holocene paleoecology and paleoenvironment of anoxic deep-sea settings in unprecedented detail.