Abiotic factors affecting the bacterial and fungal diversity of permafrost in a rock glacier in the Stelvio Pass (Italian Central Alps)

• Published in: Applied Soil Ecology
• Main Authors: Sannino C., Borruso L., Mezzasoma A., Battistel D., Ponti S., Turchetti B., Buzzini P., Guglielmin M.
• Other Authors: Sannino, C., Borruso, L., Mezzasoma, A., Battistel, D., Ponti, S., Turchetti, B., Buzzini, P., Guglielmin, M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2021
• Subjects: Abiotic parameters; Alpine permafrost; Meyerozyma spp; Microbial communities; Ice; permafrost
• Online Access: http://hdl.handle.net/11391/1494866; https://doi.org/10.1016/j.apsoil.2021.104079; https://www.sciencedirect.com/science/article/pii/S0929139321002006

The impact of climate change in the European Alps has been roughly twice the global average, dramatically reducing permafrost extent and thickening of its active layer. Therefore, the study of the abiotic factors (i.e. chemical/physical parameters) affecting the microbial diversity inhabiting Alpine permafrost appears to be of dramatic relevance. Within the European Alps, the Stelvio area exhibits these effects in a particularly evident way, with important consequences on microbial ecosystems. Therefore, microbial communities inhabiting a permafrost core collected in the Scorluzzo active rock glacier (Stelvio Pass, Italian Central Alps) were investigated along a depth gradient (410 to 524 cm from the surface). The taxonomic structures of bacterial and fungal communities were investigated via a next-generation sequencing (NGS) approach (Illumina MiSeq), targeting the bacterial V3-V4 regions of 16S rDNA and the fungal ITS2 region. Abiotic soil factors (grain size, electrical conductivity, ice/water content, pH, Loss-on-Ignition - LOI, total and organic carbon, nitrogen and phosphorous) were analysed. Richness and Shannon-H diversity indices were correlated to abiotic factors. Bacterial diversity was significantly (p < 0.05) correlated with LOI, while fungal diversity was significantly (p < 0.05) correlated with the depth gradient. The Constrained Analysis of Principal (CAP) coordinates were used to study the correlation between abiotic parameters and the taxonomic structure of bacterial and fungal communities. Among all tested variables, the depth gradient, water content, pH and LOI affected the taxonomic structure of bacterial communities (in particular, the abundance of bacterial amplicon sequence variants - ASVs - assigned to Afipia sp., Chloroflexi, Gaiella sp., Oryzihumus sp. and Serratia, sp.), while fungal communities (ASVs assigned to Naganishia sp., Rhodotorula sp., Sordariomycetes and Taphrinales) were affected by the depth gradient. Co-occurrences (calculated by Pearson correlation coefficient) ...