Massive amplicon sequencing approaches to characterize the diversity of microbial eukaryotes in sediments are scarce and controls about the effects introduced by different methods to recover DNA are lacking. In this study, we compare the performance of the melting seawater‐ice elution method on the characterization of benthic protist communities by 18S rRNA gene metabarcoding with results obtained by direct cell lysis and DNA purification from sediments. Even though the most abundant operational taxonomic units were recovered by both methods, eluted samples yielded higher richness than samples undergoing direct lysis. Both treatments allowed recovering the same taxonomic groups, although we observed significant differences in terms of relative abundance for some of them. Dinoflagellata and Ciliophora strongly dominated the community in eluted samples (> 80% reads). In directly lysed samples, they only represented 37%, while groups like Fungi and Ochrophytes were highly represented (> 20% reads respectively). Our results show that the elution process yields a higher protist richness estimation, most likely as a result of the higher sample volume used to recover organisms as compared to commonly used volumes for direct benthic DNA purification. Motile groups, like dinoflagellates and ciliates, are logically more enriched during the elution process.

中文翻译：

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融化海水冰洗方法对底栖生物界的元条形码表征的性能。

缺乏表征沉积物中微生物真核生物多样性的大规模扩增子测序方法，并且缺乏对通过不同方法回收DNA引入的效应的控制。在这项研究中，我们比较了通过18S rRNA基因metabarcoding表征底栖生物群落的融化冰冰洗脱方法的性能，以及通过直接细胞裂解和从沉积物中提取DNA的结果。即使通过这两种方法都可以回收到最丰富的操作分类单元，但洗脱样品的富集度要比直接裂解的样品高。尽管我们观察到其中一些相对丰度方面的显着差异，但这两种处理均允许恢复相同的分类组。恐龙鞭毛虫和纤毛虫在洗脱样品中占主导地位（读数大于80％）。在直接裂解的样品中，它们仅占37％，而真菌和蠕藻类等组则占很高的比例（分别大于20％的读数）。我们的结果表明，洗脱过程产生的原生质丰富度估算值更高，最可能的原因是，与直接用于底栖生物DNA纯化的常用体积相比，用于回收生物的样本量更高。在洗脱过程中，如鞭毛鞭毛和纤毛虫等能动基团在逻辑上更富集。与直接用于底栖生物DNA纯化的常用样品量相比，用于回收生物体的样品量更大是最有可能的结果。逻辑上像鞭毛鞭毛和纤毛虫这样的运动基团在洗脱过程中逻辑上更富集。与直接用于底栖生物DNA纯化的常用量相比，用于回收生物体的样本量更大是最有可能的结果。逻辑上像鞭毛鞭毛和纤毛虫这样的运动基团在洗脱过程中逻辑上更富集。