Environmental drivers of microbial communities composition following the retreat of an Alpine glacier: Microbial community composition, soil physical characterisation and biogeochemistry

The retreat of glaciers and ice sheets in response to the increase of temperature creates proglacial margins, leading to emergence of new ecosystems. Despite an increasing knowledge of microbial communities in glacier forefields through next-generation sequencing, the links between microbes (e.g. Bacteria, Archaea) and their environment remain yet poorly understood. We investigated these relationships by conducting a field campaign to the Bricola glacier (Southwestern Swiss Alps) between June and October 2023 sampling proglacial sediments following a chronosequence approach. We then analysed the samples for both soil microbiology (DNA extraction, quantification, 16S Illumina sequencing) and soil physical and biogeochemical characterisation (e.g. pH, TOC, granulometry). These two datasets contain the data used in Lardet et al (submitted in May 2025 to Arctic, Antarctic and Alpine Research) and were the base of the analyses proceeded to characterise soil microbiology and investigate the relationships with soil development and topography using multivariate statistics. The file JMF-2312-01_16S_refined_min1000_Bricola_2023.xlsx. contains the counts of Amplicon Sequence Variants (ASVs) obtained DNA extration and 16S Illumina performed at the Joint Microbiome Facility of Vienna following the protocol of Pjevac et al (2021). The ASVs were identified based on the DADA2 package (Callahan et al, 2016) and the corresponding phylogenetic table is also provided in this file. The file Data_Bricola_AAAR_2023.xlsx contains the information concerning the sampling locations (name, sampling date,time since glacier retreat, coordinates expressed in the CH1903+ LV95 Swiss coordinates system), as well as the data monitored in-situ and in laboratory. References: Callahan, B. J., Sankaran, K., Fukuyama, J. A., McMurdie, P . J., & Holmes, S. P . (2016). Bioconductor workflow for microbiome data analysis: From raw reads to community analyses. F1000Research, 5, 1492. https://doi.org/10.12688/f1000research.8986.1 Pjevac, P., Hausmann, B., Schwarz, J., Kohl, G., Herbold, C. W., Loy, A., & Berry, D. (2021). An Economical and Flexible Dual Barcoding, Two- Step PCR Approach for Highly Multiplexed Amplicon Sequencing. Frontiers in Microbiology, 12, 669776. https://doi.org/10.3389/fmicb.2021.669776