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