Genome-resolved metagenomics reveals a high diversity of novel, non-methanogenic lineages in an Andean páramo wetland

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 páramo 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 páramo 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.