Geobiological cycling of nitrogen: coupled evolution of biology and geology

The geobiological cycle of nitrogen is a coupling of the biogeochemical and geological cycles of nitrogen, which provides insights into the interactions between life and the environment and the evolution of Earth systems. The partial pressure of atmospheric nitrogen (pN₂) is a principal proxy for understanding the evolutionary history of the global geobiological cycle of nitrogen, and is also a potential biosignature of extraterrestrial life detection. Thus, it is of great significance to reconstruct the geological evolution of pN₂. In this article, the primary nitrogen reservoirs on Earth are summarized, and the processes, affecting factors and evolutionary stages of the nitrogen geobiological cycle are discussed from the perspective of nitrogen biogeochemical and geological cycles. On this basis, this article further reviews the current knowledge of the evolutionary history of p N₂ and its possible influencing factors. Finally, I raise some key issues that have to be addressed in the future.