Biocrusts from Iceland and Svalbard: Does microbial community composition differ substantially?

Abstract

A wide range of microorganisms inhabit biocrusts of arctic and sub-arctic regions. These taxa live and thrive under extreme conditions and, moreover, play important roles in biogeochemical cycling. Nevertheless, their diversity and abundance remain ambiguous. Here, we studied microbial community composition in biocrusts from Svalbard and Iceland using amplicon sequencing and epifluorescence microscopy. Sequencing of 16S rRNA gene revealed the dominance of Chloroflexi in the biocrusts from Iceland and Longyearbyen, and Acidobacteria in the biocrusts from Ny-Ålesund and South Svalbard. Within the 18S rRNA gene sequencing dataset, Chloroplastida prevailed in all the samples with dominance of Trebouxiophyceae in the biocrusts from Ny-Ålesund and Embryophyta in the biocrusts from the other localities. Furthermore, cyanobacterial number of cells and biovolume exceeded the microalgal in the biocrusts. Community compositions in the studied sites were correlated to the measured chemical parameters such as conductivity, pH, soil organic matter and mineral nitrogen contents. In addition, co-occurrence analysis showed the dominance of positive potential interactions and, bacterial and eukaryotic taxa co-occurred more frequently together.

Metagenomics Provides a Deeper Assessment of the Diversity of Bacterial Communities in Polar Soils Than Metabarcoding

“…The sampling sites for the Arctic and Antarctic samples are described in [ 11 ] and Pushkareva et al (submitted), respectively. In brief, the Arctic samples S1, S3, S7, and S8 were collected in South Svalbard, while S11 was taken in the Longyearbyen (Svalbard) surroundings and NA3 near Ny-Alesund (Svalbard).…”

“…DNA was isolated as described in [ 11 ]. Metabarcoding sequencing of the V3-4 region of rDNA of 4 replicates was performed as described in [ 11 ].…”

“…DNA was isolated as described in [ 11 ]. Metabarcoding sequencing of the V3-4 region of rDNA of 4 replicates was performed as described in [ 11 ]. The raw reads for the Arctic and Antarctic samples are available at the Sequence Read Archive (SRA) under projects PRJNA881983 and PRJNA936101, respectively.…”

“…Individual RNA sequences are commonly referred to as amplicon sequence variant (ASV) or operational taxonomical unit (OTU) and represent a species. Metabarcoding has been widely used in the last years to study community composition of soil samples (e.g., [ 9 , 10 , 11 ]).…”

“…We therefore decided to use the same DNA samples isolated from Svalbard (the Arctic) and East Antarctica for a comparison of metabarcoding and metagenomic approaches using the same bioinformatic pipeline. We will not discuss any ecological aspects of the results, which have been already published for the Arctic samples [ 11 ] and will be published soon for the Antarctic samples (Pushkareva et al, submitted).…”