The significance of the carbon cycle in the ecosystem lies in its role in regulating atmospheric carbon dioxide levels and sustaining life. It involves processes such as photosynthesis, where plants absorb CO2 and convert it into organic matter, and respiration, where organisms release CO2 back into the atmosphere. This cycle helps maintain a stable climate and supports various ecological functions, including nutrient cycling and energy flow. Understanding the carbon cycle is vital for addressing climate change and promoting environmental sustainability.