Radiation regimes shape microbial light-harvesting strategies and network organization on glacier surfaces

Glacier cryoconite hosts metabolically active microbial communities despite exposure to solar radiation, which both provides energy and imposes stress. However, how radiation regimes are associated with microbial energy acquisition strategies and ecosystem organization remains unclear. Here, we analyzed 85 cryoconite metagenomes, including 47 from Arctic glaciers and 38 from Tibetan Plateau glaciers, representing contrasting long-term radiation environments. Arctic communities show greater representation of rhodopsin-based phototrophic pathways, whereas Tibetan Plateau communities show higher potential for photosynthetic pathways. These differences are associated with distinct community structures and interaction networks. Tibetan Plateau microbiomes exhibit higher network complexity, with phototrophic taxa as highly connected network nodes, while Arctic networks are simpler and centered on rhodopsin-containing heterotrophs. Functional trait analyses further indicate higher biomass production potential in Tibetan Plateau communities. Together, our results reveal that radiation regimes are associated with divergent microbial energy acquisition strategies, with consequences for community organization and ecosystem metabolic potential in glacier cryoconite ecosystems. Arctic and Tibetan glacier cryoconite microbial communities differ in energy strategies, network organization, and metabolic potential, with rhodopsin-based phototrophy favored in the Arctic and photosynthesis in Tibet, as shown by comparative metagenomic analyses.