Algae and cyanobacteria play essential roles in moss-dominated ecosystems, contributing to nutrient cycling, primary production, and overall environmental resilience. Cyanobacteria, especially nitrogen-fixing species, supply bioavailable nitrogen to mosses in nutrient-limited habitats, like peatlands. Algae enhance photosynthesis, increasing moss productivity and influencing microecological conditions, such as moisture retention and nutrient availability. In Sphagnum-dominated peatlands, moss-cyanobacteria interactions directly affect nitrogen dynamics, peat accumulation, and long-term carbon sequestration. Understanding these associations is crucial for evaluating their ecological roles and contributions to ecosystem stability. This review synthesizes methodologies for studying moss-inhabiting microalgae and cyanobacteria, emphasizing diversity, ecological functions, and anthropogenic impacts. It concludes by identifying 12 research areas needing deeper investigation, advocating a multidisciplinary approach to advance our understanding of these symbioses and their broader ecological significance.
