What organisms need to be present to make nitrogen available?

Nitrogen availability in ecosystems is primarily facilitated by certain microorganisms. Nitrogen-fixing bacteria, such as Rhizobium, which live in symbiOSis with leguminous plants, convert atmospheric nitrogen into ammonia. Additionally, nitrifying bacteria, like Nitrosomonas and Nitrobacter, convert ammonia into nitrites and then nitrates, making nitrogen accessible to plants. Decomposers, such as fungi and bacteria, also play a crucial role by breaking down organic matter and releasing nitrogen back into the soil.