Metagenetic community analysis of epipelagic planktonic copepods in the tropical and subtropical Pacific
Metagenetic community analysis of epipelagic planktonic copepods in the tropical and subtropical Pacific
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DOI：
10.3354/meps11404
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发表时间：
2015-08-27
影响因子：
2.5
通讯作者：
Tsuda, Atsushi
中科院分区：
文献类型：
--
作者：
Hirai, Junya;Tsuda, Atsushi
鉴于浮游桡足类对海洋食物网和海洋地球化学循环的重要性，有关其大规模群落结构的信息可以增进我们对全球海洋生态系统的了解。我们进行了核大亚基核糖体DNA的宏遗传分析，以确定在热带和亚热带太平洋的上层桡足类群落结构的空间格局。宏成方法是分类学上的全面，避免了耗时的形态分类，并成功地在黑潮，北太平洋副热带环流（NPSG），热带东太平洋，南太平洋副热带环流（SPSG）的19个站的桡足类群落的特点。从434304个质量过滤的序列读数中获得了总共404个分子操作分类单位（MOTU），相似性阈值为97%。利用序列读数和MOTU组成的社区分析，我们确定了一个独特的桡足类群落的黑潮。MOTU组成之间的海洋侧的黑潮和副热带环流是相似的，但是，根据序列读数，桡足类群落聚在2组，赤道黑潮和副热带环流。这些群体与叶绿素a浓度高度相关，初级生产力似乎显着决定了桡足类在热带和亚热带太平洋的主要分布格局。多个分类群共存于贫营养亚热带环流，MOTU数和多样性指数高，特别是在NPSG。除了在副热带环流中有大量的物种分布高峰外，与SPSG相比，NPSG相对较高的生产力可能有利于一些物种在热带东太平洋和黑潮区的分布高峰，从而导致NPSG的桡足类多样性最高。
Given the significance of planktonic copepods to marine food webs and biogeochemical cycles, information about their broad-scale community structure can enhance our understanding of the global marine ecosystem. We performed a metagenetic analysis of nuclear large subunit ribosomal DNA to determine spatial patterns in the community structure of epipelagic copepods in the tropical and subtropical Pacific. The metagenetic method was taxonomically comprehensive, avoided time-consuming morphological classification, and successfully characterized copepod communities at 19 stations in Kuroshio, the North Pacific subtropical gyre (NPSG), the eastern tropical Pacific, and the South Pacific subtropical gyre (SPSG). A total of 404 molecular operational taxonomic units (MOTUs) were obtained from 434 304 quality-filtered sequence reads with a 97% similarity threshold. Using community analyses of sequence reads and MOTU compositions, we identified a distinct copepod community shoreward of the Kuroshio Current. The MOTU compositions were similar between the oceanic side of Kuroshio and the subtropical gyres; however, on the basis of sequence reads, the copepod communities were clustered in 2 groups, equator-Kuroshio and subtropical gyre. These groups were highly correlated with chl a concentrations, and primary productivity appeared to significantly determine the major distribution patterns of copepods in the tropical and subtropical Pacific. Multiple taxonomic groups co-existed in the oligotrophic subtropical gyres, where MOTU numbers and diversity indices were high, particularly in the NPSG. In addition to the large number of species with distribution peaks in the subtropical gyres, the relatively high productivity in the NPSG compared with the SPSG might favor some species with distribution peaks in the eastern tropical Pacific and Kuroshio regions, leading to the highest copepod diversity in the NPSG.