Final answer:
The Nitrogen Cycle describes how nitrogen is converted into forms usable by living organisms through processes like nitrogen fixation, decay, nitrification, and denitrification, involving symbiotic bacteria and ensuring the continuous availability of this essential nutrient.
Step-by-step explanation:
The Nitrogen Cycle is a fundamental biogeochemical cycle that ensures the continuous supply of nitrogen in a form that can be utilized by living organisms. It consists of four critical processes: nitrogen fixation, decay, nitrification, and denitrification. Through nitrogen fixation, nitrogen-fixing bacteria convert nitrogen gas from the atmosphere into nitrates that plants can absorb and utilize. During decay, organic nitrogen is decomposed into ammonia by decomposers. Subsequently, nitrification processes convert ammonia into nitrites and then nitrates, which plants can then take up. Lastly, denitrification by other types of bacteria converts nitrates back into nitrogen gas, which re-enters the atmosphere, thus completing the cycle.
These processes play crucial roles in maintaining the ecosystem as they help recycle nitrogen through both biotic (living organisms such as plants and bacteria) and abiotic (non-living elements like water and soil) components of the environment. Without this cycle, the vast reservoir of nitrogen gas in the atmosphere (constituting 78%) would remain inaccessible to most life forms, significantly impacting the biosynthesis of essential molecules like proteins and nucleic acids.