Microbial interaction networks as climate thermometers: redefining temperature sensitivity of aerobic methanotrophy in freshwater ecosystems.

Abstract

Methane-oxidizing bacteria (MOB) serve as critical biogeochemical gatekeepers, mitigating methane (CH₄) emissions from freshwaters through aerobic methanotrophy. However, their global biogeography, interaction networks, and thermal responsiveness are poorly understood. We synthesize global patterns revealing a latitudinal succession, with Methylococcaceae dominating in tropical and temperate regions, Beijerinckiaceae prevailing in the polar region, and temperate region exhibiting the highest richness (10.7 ± 0.32) and Shannon diversity (1.51 ± 0.02). Climate-driven interactions show tightly intertwined MOB-associated subnetworks in tropical and polar regions, thereby amplifying the temperature sensitivity of aerobic methanotrophy (0.24 and 0.16 μmol·L^-1·d^-1·°C^-1), while in the temperate region, the subnetworks are sparser and show low temperature sensitivity. Crucially, our results reveal that nontrophic interactions, rather than taxonomic diversity, drive the temperature sensitivity of aerobic methanotrophy. These insights position MOB interactions as predictive bioindicators of CH₄ flux under warming, improving climate models and guiding strategies for emission mitigation.