The process in which bacteria convert nitrates back into nitrogen gas is known as denitrification. This microbial process completes the nitrogen cycle by reducing nitrates in the soil to gaseous nitrogen, which is then released into the atmosphere. Denitrification helps maintain the balance of nitrogen in ecosystems and prevents the accumulation of excess nitrates, which can lead to environmental issues such as eutrophication. Understanding this process is essential for agriculture, environmental management, and overall ecosystem health.