What role does nutrient cycling play in ecological systems?

Nutrient cycling is fundamental to ecological systems because it ensures that essential nutrients are recycled and made available for living organisms. In an ecosystem, nutrients from dead organic matter, waste products, and other sources are decomposed by microorganisms, returning them to the soil and making them accessible for plants. This process facilitates plant growth and supports the entire food web, as plants are primary producers that provide energy and resources for herbivores and, subsequently, for carnivores.

The availability of these nutrients is crucial for the survival and health of organisms within the ecosystem, as they are needed for processes such as growth, reproduction, and metabolic functions. Without an effective nutrient cycling system, ecosystems would become depleted of vital nutrients, ultimately leading to a decline in biodiversity and the functioning of the ecosystem.

In contrast, other choices mention aspects like sunlight and energy flow, which, while important in their own right, do not directly describe the specific role of nutrient cycling in maintaining the availability of essential nutrients for organisms.