We analysed a widely used barcode, the V9 region of the 18S rRNA gene, to study the effect of environmental conditions on the distribution of two related heterotrophic protistan lineages in marine plankton, kinetoplastids and diplonemids. We relied on a major published dataset (Tara Oceans) where samples from the mesopelagic zone were available from just 32 of 123 locations, and both groups are most abundant in this zone. To close sampling gaps and obtain more information from the deeper ocean, we collected 57 new samples targeting especially the mesopelagic zone. We sampled in three geographic regions: the Arctic, two depth transects in the Adriatic Sea, and the anoxic Cariaco Basin. In agreement with previous studies, both protist groups are most abundant and diverse in the mesopelagic zone. In addition to that, we found that their abundance, richness, and community structure also depend on geography, oxygen concentration, salinity, temperature, and other environmental variables reflecting the abundance of algae and nutrients. Both groups studied here demonstrated similar patterns, although some differences were also observed. Kinetoplastids and diplonemids prefer tropical regions and nutrient‐rich conditions and avoid high oxygen concentration, high salinity, and high density of algae.

中文翻译：

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环境因素决定海洋中浮游二烯酮和动质体的分布。

我们分析了一种广泛使用的条形码，即18S rRNA基因的V9区域，以研究环境条件对海洋浮游生物，运动质体和二倍体类动物中两个相关异养性前列腺素谱系分布的影响。我们依赖于一个主要的已发布数据集（塔拉海洋），其中仅来自123个位置中的32个来自中古生境带的样本，并且两组在该区域中数量最多。为了缩小采样间隔并从更深的海洋中获取更多信息，我们收集了57个新的样品，这些样品特别针对中弹性带。我们在三个地理区域进行了采样：北极，亚得里亚海的两个深度横断面和缺氧的卡里亚科盆地。与先前的研究一致，中视界带的两个原生生物群体最为丰富和多样。除此之外，我们发现他们的数量丰富，丰富度和群落结构还取决于地理，氧气浓度，盐度，温度以及其他反映藻类和营养物质丰富的环境变量。尽管也观察到一些差异，但在这里研究的两组都显示出相似的模式。运动质体和二倍体类动物更喜欢热带地区和营养丰富的条件，并避免高氧气浓度，高盐度和高密度藻类。