atmospheric nitrogen

Atmospheric nitrogen refers to the large amount of nitrogen gas (N₂) present in our air—about 78% of it. It’s a stable, inert molecule that makes up most of Earth’s atmosphere. While essential for all living organisms, nitrogen gas is not directly usable by most plants and animals. Instead, it must be converted into reactive forms like ammonia or nitrates through processes like nitrogen fixation, primarily by certain bacteria. This nitrogen cycle is vital for synthesizing proteins and DNA, supporting life, and maintaining ecological balance.