Eukaryotic diversity in late Pleistocene marine sediments around a shallow methane hydrate deposit in the Japan Sea
Eukaryotic diversity in late Pleistocene marine sediments around a shallow methane hydrate deposit in the Japan Sea
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DOI：
10.1111/gbi.12233
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发表时间：
2017-09
期刊：
影响因子：
3.7
通讯作者：
M. Kouduka;Akifumi S. Tanabe;Satoshi Yamamoto;Katsunori Yanagawa;Y. Nakamura;F. Akiba;Hitoshi Tomaru;Hirokazu Toju;Yohey Suzuki
中科院分区：
文献类型：
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作者：
M. Kouduka;Akifumi S. Tanabe;Satoshi Yamamoto;Katsunori Yanagawa;Y. Nakamura;F. Akiba;Hitoshi Tomaru;Hirokazu Toju;Yohey Suzuki
海洋沉积物含有从上覆水柱沉积的真核DNA。然而，在浅海沉积物中，沉积的真核生物DNA中有很大一部分是好氧生物降解的。冷泉沉积物在靠近沉积物-水界面处往往是厌氧的，因此，这类沉积物中的真核生物DNA有望得到保存。我们调查了深埋在日本海的海洋沉积物，那里的甲烷水合物存款与冷泉。定量PCR分析显示，在海洋沉积物中的真核生物DNA的可重复恢复深度可达31.0米附近的甲烷水合物存款。与此相反，真核生物DNA的可重复恢复仅限于浅深度（8.3米），在海洋沉积物不相邻的甲烷水合物存款在同一地区。18 S rRNA基因可变区的焦磷酸测序每个样品产生1，276 - 3，307个读数，这足以覆盖基于稀疏曲线的生物多样性。系统发育分析表明，大部分的真核DNA起源于放射虫属Chaunacanthida类，其中有SrSO 4骨架，海草属Zostera，海藻属马尾藻属。还检测到来自其他水生动物和陆生植物的真核DNA。与海链藻属密切相关的硅藻序列，指示寒冷的气候，从沉积物中获得在末次冰期（MIS-2）。Alnus、Micromonas和Ulmus属的植物序列在温暖的海间期（MIS-3）沉积的沉积物中被发现。这些结果表明，与冷泉相关的海洋沉积物中陆地和水生来源的真核DNA的长期存在，以及来自与冷泉相关的深埋海洋沉积物的真核DNA的遗传信息可用于重建过去的环境和生态系统。
Marine sediments contain eukaryotic DNA deposited from overlying water columns. However, a large proportion of deposited eukaryotic DNA is aerobically biodegraded in shallow marine sediments. Cold seep sediments are often anaerobic near the sediment–water interface, so eukaryotic DNA in such sediments is expected to be preserved. We investigated deeply buried marine sediments in the Japan Sea, where a methane hydrate deposit is associated with cold seeps. Quantitative PCR analysis revealed the reproducible recovery of eukaryotic DNA in marine sediments at depths up to 31.0 m in the vicinity of the methane hydrate deposit. In contrast, the reproducible recovery of eukaryotic DNA was limited to a shallow depth (8.3 m) in marine sediments not adjacent to the methane hydrate deposit in the same area. Pyrosequencing of an 18S rRNA gene variable region generated 1,276–3,307 reads per sample, which was sufficient to cover the biodiversity based on rarefaction curves. Phylogenetic analysis revealed that most of the eukaryotic DNA originated from radiolarian genera of the class Chaunacanthida, which have SrSO4 skeletons, the sea grass genus Zostera, and the seaweed genus Sargassum. Eukaryotic DNA originating from other planktonic fauna and land plants was also detected. Diatom sequences closely related to Thalassiosira spp., indicative of cold climates, were obtained from sediments deposited during the last glacial period (MIS‐2). Plant sequences of the genera Alnus, Micromonas, and Ulmus were found in sediments deposited during the warm interstadial period (MIS‐3). These results suggest the long‐term persistence of eukaryotic DNA from terrestrial and aquatic sources in marine sediments associated with cold seeps, and that the genetic information from eukaryotic DNA from deeply buried marine sediments associated with cold seeps can be used to reconstruct environments and ecosystems from the past.