Genome-resolved metagenomics reveals abundant novel, non-methanogenic lineages in tropical alpine paramo soils

Wetlands are the largest natural source of atmospheric methane, yet tropical high-altitude wetlands remain underrepresented in global climate frameworks. Here, we investigated soil metagenomes from the paramo ecosystem in Chingaza National Natural Park (Colombia) across three vegetation-defined ecosites. Microbial community composition differed significantly among ecosites, with peatland soils exhibiting the highest diversity. Genome-resolved metagenomics recovered 109 high-quality metagenome-assembled genomes (MAGs), of which 37.6% represent phylogenetically novel lineages absent from current genomic databases. These novel taxa were not restricted to the rare biosphere but comprised abundant members of the reconstructed community, highlighting a substantial gap in global microbial reference frameworks. Functional analyses revealed widespread carbon fixation potential via the Wood-Ljungdahl pathway and complementary bacterial pathways, but no evidence of methanogenesis: genes encoding the methyl-coenzyme M reductase complex (mcrABG) were absent across all MAGs. Instead, metabolic potential was consistent with acetogenic carbon fixation coupled to sulfate reduction, suggesting an alternative carbon cycling regime relative to canonical methane-producing wetlands. Together, these results identify the tropical alpine paramo as a reservoir of abundant and phylogenetically novel microbial diversity with distinct metabolic potential. Incorporating these lineages into global databases will be essential for improving predictions of carbon cycling in underrepresented high-altitude ecosystems.