The significance of the nitrogen cycle for ecosystems lies in its critical role in nutrient availability and overall ecosystem productivity. Through processes like nitrogen fixation, nitrification, and denitrification, nitrogen is converted into various forms that plants and animals can utilize. This cycle supports plant growth, contributing to food webs and biodiversity. Disruptions in the nitrogen cycle, often caused by human activities, can lead to eutrophication and detrimental ecological consequences, highlighting its importance for ecosystem health.