Global Research Trends and Thematic Evolution in Rhizosphere Oxygen Environments and Microbial Communities: A Bibliometric Review from 1980 to 2026

Oxygen supply and consumption create heterogeneous rhizosphere environments that regulate microbial activity and biogeochemical transformations. This study combines bibliometric analysis with a synthesis of representative research to characterize the development of this field. A screened collection of 2459 Web of Science publications from 1980 to 2026 was analyzed using publication statistics, collaboration networks, author–keyword co-occurrence, and burst detection. Annual output increased overall, with an intervening period of fluctuation and renewed expansion after 2010. China, the United States, and Germany were the leading contributors. The keyword network resolved six interconnected themes encompassing symbiotic nitrogen fixation, rice-associated microbial communities and contaminants, wetland aeration and methane processes, rhizosphere nutrient and redox transformations, constructed-wetland nitrogen removal, and reactive oxygen species and root exudates. Recent bursts in microbial community and reactive oxygen species, together with work on root exudates and iron plaque, highlight growing attention to the biological regulation of rhizosphere processes. The mechanistic literature shows that roots can act as oxygen sources or sinks, and that the consequences for carbon, nitrogen, and contaminant transformations depend on substrate supply and the spatial and temporal arrangement of redox microsites. Linking oxygen imaging with isotope tracing, microbial functional experiments, and field-scale flux measurements offers a route to connect these microsite processes with ecosystem outcomes.