Nutrient cycling in ecosystems refers to the continuous movement of essential nutrients through biotic (living) and abiotic (non-living) components. This process involves various trophic levels, including producers, consumers, and decomposers, which interact to recycle nutrients necessary for growth and survival. Key cycles include the carbon cycle, nitrogen cycle, and phosphorus cycle, which ensure that vital elements are available at different stages of an ecosystem. Nutrient cycling supports ecosystem productivity and plays a crucial role in maintaining ecological balance.