ABSTRACT
The phylum Caldiserica was identified from the hot spring 16S rRNA gene lineage 'OP5' and named for the sole isolate Caldisericum exile, a hot spring sulfur-reducing chemoheterotroph. Here we characterize 7 Caldiserica metagenome-assembled genomes (MAGs) from a thawing permafrost site in Stordalen Mire, Arctic Sweden. By 16S rRNA and marker gene phylogenies, and average nucleotide and amino acid identities, these Stordalen Mire Caldiserica (SMC) MAGs form part of a divergent clade from C. exile. Genome and meta-transcriptome and proteome analyses suggest that unlike Caldisericum, the SMCs (i) are carbohydrate- and possibly amino acid fermenters that can use labile plant compounds and peptides, and (ii) encode adaptations to low temperature. The SMC clade rose to community dominance within permafrost, with a peak metagenome-based relative abundance of â¼60%. It was also physiologically active in the upper seasonally-thawed soil. Beyond Stordalen Mire, analysis of 16S rRNA gene surveys indicated a global distribution of this clade, predominantly in anaerobic, carbon-rich and cold environments. These findings establish the SMCs as four novel phenotypically and ecologically distinct species within a single novel genus, distinct from C. exile clade at the phylum level. The SMCs are thus part of a novel cold-habitat phylum for an understudied, globally-distributed superphylum encompassing the Caldiserica. We propose the names Candidatus Cryosericota phylum nov., Ca. Cryosericia class nov., Ca. Cryosericales ord. nov., Ca. Cryosericaceae fam. nov., Ca. Cryosericum gen. nov., Ca. Cryosericum septentrionale sp. nov., Ca. C. hinesii sp. nov., Ca. C. odellii sp. nov., and Ca. C. terrychapinii sp. nov.
Subject(s)
Bacteria/classification , Permafrost/microbiology , Phylogeny , Bacteria/genetics , Bacteria/isolation & purification , Bacterial Typing Techniques , Cold Temperature , DNA, Bacterial/genetics , Metagenome , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA , SwedenABSTRACT
The traditional subsistence activities of Indigenous communities in Canada's subarctic are being affected by the impacts of climate change, compounding the effects of social, economic and political changes. Most research has focused on hunting and fishing activities, overlooking berry picking as an important socio-cultural activity and contributor to the diversity of food systems. We examined the vulnerability of cloudberry (referred to as 'bakeapple' consistent with local terminology) picking to environmental changes in the community of Cartwright, Labrador using semi-structured interviews (n = 18), field surveys, and satellite imagery. We identified the components of vulnerability including: the environmental changes affecting the abundance, quality, and ripening time of bakeapples (i.e., exposure), the characteristics of the community that affect how these changes have local impacts (i.e., sensitivity), and the ways in which the community is responding to environmental changes (i.e., adaptive capacity). Our results confirm that environmental changes related to permafrost, vegetation, and water have occurred at the bakeapple picking grounds with observed impacts on bakeapples. It is becoming increasingly difficult for bakeapple pickers to respond to variable growth as in the past because of changes in summer settlement patterns that place families farther from their bakeapple patches. We conclude that harvesters in Cartwright have high adaptive capacity to respond to environmental changes due to their knowledge of their bakeapple patches, and at present, socioeconomic changes have had a greater impact than environmental changes on their harvesting capacity.
