Abstract
Global climate change threatens food security, with paddy fields being major greenhouse gas sources. Microalgae,as novel inoculants, show contested emission effects and unclear synergy with phycosphere bacteria.Integrating meta-analysis and incubation experiments, we systematically investigated microalgae-bacteria interactionsin black soil paddy fields. Microalgae significantly increased the response ratio of soil organic carbon(+1.0644, 95% CI: +0.7625 to +1.3663) and reduced the response ratio of methane emissions (-1.1713, 95%CI: -1.7316 to - 0.611). Live-microalgae drove methane mitigation via a dual-pathway, suppressing mcrA andenhancing pmoA gene abundance, enriching type Ⅰ methanotrophs (e.g., Methylobacter) while inhibiting keymethanogens. Microalgae specifically recruited abundant, diverse phycosphere bacteria, forming functionalmicroniches. The microalgae-bacteria consortium (MA + B) exhibited optimal synergy, reducing CH4 emissionsby 47.78%, and increasing SOC by 5.71%, linked to elevated dissolved oxygen, extracellular polymeric substances, and bacterial-derived carbon. This study reveals microalgae enhance carbon sequestration by reshaping microbial networks, offering a new paradigm for sustainable agriculture.
NETL
NSTL
Elsevier