Biosphere-atmosphere interactions is the research field investigating the complex, reciprocal exchanges of energy, matter (including trace gases and aerosols), and momentum between Earth's living organisms and ecosystems (biosphere) and its gaseous envelope (atmosphere). This concept explores how biological processes influence atmospheric composition, structure, and dynamics, while concurrently examining how atmospheric conditions affect the function, distribution, and evolution of life, thereby underpinning our understanding of Earth's climate system, biogeochemical cycles, and environmental change.