Metabarcoding data reveal vertical multitaxa variation in topsoil communities during the colonization of deglaciated forelands

Ice-free areas are increasing worldwide due to the dramatic glacier shrinkage and are undergoing rapid colonization by multiple lifeforms, thus representing key environments to study ecosystem development. Soils have a complex vertical structure. However, we know little about how microbial and animal communities differ across soil depths and development stages during the colonization of deglaciated terrains, how these differences evolve through time, and whether patterns are consistent among different taxonomic groups. Here, we used environmental DNA metabarcoding to describe how community diversity and composition of six groups (Eukaryota, Bacteria, Mycota, Collembola, Insecta, Oligochaeta) differ between surface (0-5 cm) and relatively deep (7.5-20 cm) soils at different stages of development across five Alpine glaciers. Taxonomic diversity increased with time since glacier retreat and with soil evolution; the pattern was consistent across different groups and soil depths. For Eukaryo..., Libraries were prepared following the MetaFast protocol (Taberlet et al., 2018) and sequenced using the MiSeq (Bact02 and Fung02) or HiSeq 2500 (Arth02, Coll01, Euka02, Inse01, Olig01, Sper01) Illumina platforms (Illumina, San Diego, CA, USA) with a paired-end approach (2 × 250 bp for Bact02 and Fung02, and 2 × 150 bp for the others markers) at Fasteris (SA, Geneva, Switzerland). For each marker, the sequence depth corresponded to 10,000 reads per sample., Sequence data have been processed using the OBITools software suit (version 1.2.9) then filtered and analyzed in R (version 4.0). All scripts to reproduce data processing are provided here and described in the \"Methods\" section of the manuscript. See \"Data Accessibility\" section of the manuscript to access raw sequence data.Â受冰川急剧消融影响，全球无冰区域面积持续扩张，并正被多种生命类群快速定植，因此成为研究生态系统发育过程的关键环境载体。土壤具有复杂的垂直分层结构。然而在冰碛裸露区域的定植过程中，我们对微生物与动物群落在不同土壤深度及发育阶段的差异、这些差异随时间的演变规律，以及不同分类类群间是否存在一致的分布模式仍知之甚少。本研究采用环境DNA元条形码（environmental DNA metabarcoding）技术，针对阿尔卑斯山脉五处冰川沿线不同发育阶段的土壤，分析了表层（0-5 cm）与深层（7.5-20 cm）土壤中6个类群——真核生物域（Eukaryota）、细菌域（Bacteria）、真菌界（Mycota）、弹尾纲（Collembola）、昆虫纲（Insecta）与寡毛纲（Oligochaeta）——的群落多样性与组成差异。就真核生物[...]，测序文库按照MetaFast（MetaFast）实验流程（Taberlet等，2018）构建，并于瑞士日内瓦的Fasteris公司（SA, Geneva, Switzerland）使用Illumina（Illumina）测序平台完成测序：其中针对Bact02与Fung02标记采用MiSeq（MiSeq）测序平台，其余标记（Arth02、Coll01、Euka02、Inse01、Olig01、Sper01）采用HiSeq 2500（HiSeq 2500）测序平台，均采用双端测序模式——Bact02与Fung02的读长为2×250 bp，其余标记为2×150 bp。每个标记引物对应的测序深度为每个样本10000条测序读段。测序数据采用OBITools软件套件（OBITools，版本1.2.9）进行预处理，随后在R语言（R，版本4.0）环境中完成过滤与分析。本研究提供了可复现数据处理流程的所有代码，相关说明详见论文的「方法」部分；原始测序数据的获取方式请参阅论文的「数据可及性」部分。