ABSTRACT

The diversity of protists was researched in the Alboran Sea (SW Mediterranean Sea) by means of high-throughput sequencing technologies based on the amplification of the V9 region of 18S rRNA. Samples were collected at different depths in seven stations following an environmental gradient from a coastal upwelling zone to the core of an oligotrophic anticyclonic gyre (AG). Sampling was performed during summer, when the water column was stratified. The superphyla Alveolata, Stramenopila and Rhizaria accounted for 84% of the total operational taxonomic units (OTUs). The most diverse groups were Dinophyceae (21% of OTUs), Marine Alveolates-II (MALV-II; 20%), Ciliophora (9%) and MALV-I (6%). In terms of read abundance, the predominant groups were Dinophyceae (29%), Bacillariophyta (14%), MALV-II (11%) and Ciliophora (11%). Samples were clustered into three groups according to the sampling depth and position. The shallow community in coastal stations presented distinguishable patterns of diatoms and ciliates compared with AG stations. These results indicate that there was a strong horizontal coupling between phytoplankton and ciliate communities. Abundance of Radiolaria and Syndiniales increased with depth. Our analyses demonstrate that the stratification disruption produced by the AG caused shifts in the trophic ecology of the plankton assemblages inducing a transition from bottom-up to top-down control.

中文翻译：

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与阿尔波兰海（地中海）的反气旋回旋相关的生物界的变化

摘要

通过基于18S rRNA V9区域扩增的高通量测序技术，在Alboran Sea（西南地中海）研究了原生生物的多样性。从沿海上升流区到贫营养性反气旋回旋管（AG）的中心，随着环境梯度的变化，在七个站点的不同深度收集了样本。在夏季，当水柱分层时进行采样。上叶植物Alveolata，Stramenopila和Rhizaria占总操作分类单位（OTU）的84％。种类最多的是恐龙科（占OTU的21％），海藻-II（MALV-II； 20％），纤毛虫（9％）和MALV-1（6％）。就阅读丰度而言，主要人群为恐龙科（29％），杆菌属（14％），MALV-II（11％）和纤毛虫（11％）。根据采样深度和位置将样本分为三类。与AG站相比，沿海站的浅层群落呈现出明显的硅藻和纤毛模式。这些结果表明，浮游植物和纤毛虫群落之间存在很强的水平耦合。放射虫和Syndiniales的丰度随深度增加。我们的分析表明，由AG产生的分层破坏导致了浮游生物组合的营养生态学变化，从而导致了由下而上到自上而下的控制转变。这些结果表明，浮游植物和纤毛虫群落之间存在很强的水平耦合。放射虫和Syndiniales的丰度随深度增加。我们的分析表明，由AG产生的分层破坏导致了浮游生物组合的营养生态学变化，从而导致了由下而上到自上而下的控制转变。这些结果表明，浮游植物和纤毛虫群落之间存在很强的水平耦合。放射虫和Syndiniales的丰度随深度增加。我们的分析表明，由AG产生的分层破坏导致了浮游生物组合的营养生态学变化，从而导致了由下而上到自上而下的控制转变。