Oxygen minimum zones (OMZs) support ocean biogeochemical cycles of global importance. The OMZ off central Chile is characterized by seasonally variable oxygen concentrations due to upwelling events. Bacterial and archaeal communities from this area have been previously described; however, picoeukaryote communities remain largely unexplored. In order to improve our knowledge on picoeukaryote ecology and the effect of controlling factors on its community structure, environmental parameters and 18S rRNA metabarcoding analyses were performed in water samples collected at several depths at a time series station on the continental shelf in March, May and August. Our results showed that oxygen, nitrate, silicate and temperature are relevant factors shaping the picoeukaryote community structure. Overall, according to our sequence dataset, the OMZ was dominated by Dinophyceae members including marine parasitic dinoflagellates. Moreover, dysoxic and suboxic conditions were enriched by fungi and phagotrophic protists from Ustilaginomycetes, Bicoecea and Choanoflagellatea. The latter is particularly relevant in the understanding of metazoan evolution and the origins of multicellularity in low-oxygen environments. Picoeukaryote communities changed significantly over the 3 months sampled with variations in water column stratification, including the occurrence of a winter bloom of Mamiellales. Altogether, this study reveals a great diversity and dynamics of picoeukaryotes inhabiting a coastal OMZ.

中文翻译：

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智利中部以外的不同氧气环境塑造了微型微核生物集合体，使氧气最小区域水旺盛

最低氧区（OMZ）支持具有全球重要性的海洋生物地球化学循环。智利中部附近的OMZ的特征是由于上升事件而季节性变化的氧气浓度。先前已经描述了该地区的细菌和古细菌群落；但是，皮古真核生物群落基本上尚未开发。为了提高我们对微型真核生物生态学的认识以及控制因素对其群落结构的影响，在三月，五月和五月在大陆架的一个时间序列站对几个深度收集的水样中进行了环境参数和18S rRNA元条形码分析。八月。我们的结果表明，氧气，硝酸盐，硅酸盐和温度是影响微核生物群落结构的相关因素。总体而言，根据我们的序列数据集，OMZ主要由恐龙科成员组成，包括海洋寄生的鞭毛藻。此外，来自Ustilaginomycetes，Bicoecea和Choanoflagellateatea的真菌和吞噬营养的原生生物丰富了低氧和低氧条件。后者在了解后生动物进化和低氧环境中多细胞性的起源方面特别重要。在采样的3个月中，皮克真核生物群落发生了显着变化，水柱分层也有所变化，包括发生了Mamiellales的冬季开花。总而言之，这项研究揭示了居住在沿海OMZ中的微型真核生物的多样性和动态。Bicoecea和Choanoflagellatea。后者在了解后生动物进化和低氧环境中多细胞起源方面特别重要。在采样的3个月中，皮克真核生物群落发生了显着变化，水柱分层也有所变化，包括发生了Mamiellales的冬季开花。总而言之，这项研究揭示了居住在沿海OMZ中的微型真核生物的多样性和动态。Bicoecea和Choanoflagellatea。后者在了解后生动物进化和低氧环境中多细胞起源方面特别重要。在三个月的采样中，皮克真核生物群落发生了显着变化，水柱分层也有所变化，包括冬季出现了Mamiellales。总而言之，这项研究揭示了居住在沿海OMZ中的微型真核生物的多样性和动态。