The meiofauna is an important part of the marine ecosystem, but its composition and distribution patterns are relatively unexplored. Here we assessed the biodiversity and community structure of meiofauna from five locations on the Swedish western and southern coasts using a high-throughput DNA sequencing (metabarcoding) approach. The mitochondrial cytochrome oxidase 1 (COI) mini-barcode and nuclear 18S small ribosomal subunit (18S) V1-V2 region were amplified and sequenced using Illumina MiSeq technology. Our analyses revealed a higher number of species than previously found in other areas: thirteen samples comprising 6.5 dm3 sediment revealed 708 COI and 1,639 18S metazoan OTUs. Across all sites, the majority of the metazoan biodiversity was assigned to Arthropoda, Nematoda and Platyhelminthes. Alpha and beta diversity measurements showed that community composition differed significantly amongst sites. OTUs initially assigned to Acoela, Gastrotricha and the two Platyhelminthes sub-groups Macrostomorpha and Rhabdocoela were further investigated and assigned to species using a phylogeny-based taxonomy approach. Our results demonstrate that there is great potential for discovery of new meiofauna species even in some of the most extensively studied locations.

中文翻译：

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沙粒之间的生物多样性：通过元条形码评估瑞典南部和西部的小型动物组成。


小型底栖动物是海洋生态系统的重要组成部分，但其组成和分布模式相对尚未被探索。在这里，我们使用高通量 DNA 测序（元条形码）方法评估了瑞典西部和南部海岸五个地点的小型底栖动物的生物多样性和群落结构。使用 Illumina MiSeq 技术对线粒体细胞色素氧化酶 1 (COI) 迷你条形码和核 18S 小核糖体亚基 (18S) V1-V2 区域进行扩增和测序。我们的分析显示，物种数量比之前在其他地区发现的要多：包含 6.5 dm3 沉积物的 13 个样本显示出 708 个 COI 和 1,639 个 18S 后生动物 OTU。在所有地点，大多数后生动物生物多样性属于节肢动物、线虫动物和扁形动物。 α和β多样性测量表明，不同地点的群落组成存在显着差异。最初分配给 Acoela、Gastrotricha 和两个扁形动物亚群 Macrostomorpha 和 Rhabdocoela 的 OTU 被进一步研究，并使用基于系统发育的分类方法分配给物种。我们的结果表明，即使在一些研究最广泛的地点，发现新的小型动物物种也具有巨大的潜力。