Metabolic capacities and potential microbial interactions in red and green snow of the Antarctic Peninsula

Colored (red and green) snow is widespread in Antarctica due to climate warming. This phenomenon reduces snow albedo, accelerates snowmelt, alters microbial functions, and impacts regional geochemical cycles. Diverse microorganisms are associated with this phenomenon, yet their functions remain poorly understood. We employed metagenomic sequencing to reveal the metabolic interactions and functional specialization within microbial communities of colored snow, focusing on carbon, nitrogen, phosphorus, and sulfur metabolism. While broad metabolic profiles were similar between red and green snow, targeted analysis of specific pathways revealed significant enrichment of denitrification and organic-phosphorus mineralization genes in green snow and labile carbon degradation genes in red snow. Betaproteobacteria were dominant drivers of nitrogen, sulfur, and phosphorus transformation, while diverse eukaryotic algae and bacteria were responsible for carbon fixation. Additionally, we recovered 2257 bacteriophages, 529 algal viruses, and 2302 secondary metabolite gene clusters. Specifically, viruses encoded 126 auxiliary metabolic genes that may influence the elemental cycling of hosts, while secondary metabolites, such as pyoverdine, may assist algal iron acquisition. Our findings offer new insights into the metabolic potentials and interactions of microbial communities in Antarctic colored snow, highlighting their potential relevance to snow biogeochemical processes.