ABSTRACT: We used 18S rRNA gene metabarcoding to investigate picoeukaryotic diversity and distribution at the surface and deep chlorophyll maximum (DCM) of 4 stations in the eastern equatorial Indian Ocean (EEIO). The results showed that picoeukaryotic communities were dominated by 5 phyla: Dinoflagellata, Radiolaria, Chlorophyta, Ochrophyta and Ciliophora. The picoeukaryotic communities were classified into 3 groups matching their water mass origins and depth: (1) Group I was in the surface waters of the Bay of Bengal, which had low salinity, and was dominated by Radiolaria Group A, Spirotrichea and marine stramenopiles; (2) Group II was in the DCM within the intrusion of Arabian Sea high salinity water, in which Chloropicophyceae and Pelagophyceae were more abundant; and (3) Group III was located in the 0°-5°S surface water, which was enriched by Dinophyceae. In addition, Caecitellaceae paraparvulus was abundant at 4°S, where weak vertical mixing occurred. This study provides the first baseline of picoeukaryotic diversity in the EEIO.

中文翻译：

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元条形码揭示的赤道东印度洋微微核生物的多样性

摘要：我们使用18S rRNA基因元条形码研究了赤道​​东印度洋（EEIO）4个站点的表核和深叶绿素最大值（DCM）的微核生物多样性和分布。结果表明，皮原核生物群落以5种门为主：恐龙鞭毛纲，放射线虫，绿藻，O虫科和纤毛虫。微型真核生物群落根据其水质起源和深度分为三类：（1）第一类在孟加拉湾地表水域中，盐度低，主要由放射虫A组，螺旋藻和海生层甲虫为主。（2）第II类群位于阿拉伯海高盐度水入侵的DCM中，其中藻科和伞形科更为丰富；（3）第III组位于0°-5°S地表水中，这是由Dinophyceae丰富的。此外，伞形科在4°S盛产，垂直混合较弱。该研究提供了EEIO中微核真核生物多样性的第一个基线。