SRX027105 Bacterial community SRP003568 Arctic tundra PCR was carried out using genomic DNA as template with modified 16S rRNA primers (which, in addition to targeting the bacterial 16S rRNA gene, also contain regions specific to Illumina paired-end sequencing primers and contain regions necessary to bind to the Illumina flow cell). Following this PCR products of the correct size were recovered using the QIAquick gel extraction kit (Qiagen. USA). SRS115045 Bacterial community AT1 AMPLICON METAGENOMIC PCR 0 Application Read Forward 1 1 Application Read Reverse 126 Illumina Genome Analyzer II SRX027106 Bacterial community (control 1) SRP003568 Arctic tundra PCR was carried out using genomic DNA as template with modified 16S rRNA primers (which, in addition to targeting the bacterial 16S rRNA gene, also contain regions specific to Illumina paired-end sequencing primers and contain regions necessary to bind to the Illumina flow cell). Following this PCR products of the correct size were recovered using the QIAquick gel extraction kit (Qiagen. USA). SRS115045 Bacterial community C1 AMPLICON METAGENOMIC PCR 0 Application Read Forward 1 1 Application Read Reverse 126 Illumina Genome Analyzer II SRX027988 Bacterial community (alert 2) SRP003568 Arctic tundra PCR was carried out using genomic DNA as template with modified 16S rRNA primers (which, in addition to targeting the bacterial 16S rRNA gene, also contain regions specific to Illumina paired-end sequencing primers and contain regions necessary to bind to the Illumina flow cell). Following this PCR products of the correct size were recovered using the QIAquick gel extraction kit (Qiagen. USA). SRS115045 Bacterial community AT2 AMPLICON METAGENOMIC PCR 0 Application Read Forward 1 1 Application Read Reverse 126 Illumina Genome Analyzer II SRX027989 Bacterial community (control 2) SRP003568 Arctic tundra PCR was carried out using genomic DNA as template with modified 16S rRNA primers (which, in addition to targeting the bacterial 16S rRNA gene, also contain regions specific to Illumina paired-end sequencing primers and contain regions necessary to bind to the Illumina flow cell). Following this PCR products of the correct size were recovered using the QIAquick gel extraction kit (Qiagen. USA). SRS115045 Bacterial community C2 AMPLICON METAGENOMIC PCR 0 Application Read Forward 1 1 Application Read Reverse 126 Illumina Genome Analyzer II