What is meant by "biological control" in ecological systems?

Biological control refers to the action of organisms, such as predators, parasites, or pathogens, that help regulate the population levels of other organisms, thereby keeping pest populations in check naturally. This process promotes ecological balance and can reduce the need for synthetic chemical pest control methods. By allowing certain organisms to thrive, biological control harnesses natural interactions within ecosystems to manage pest populations effectively.

This definition is critical for understanding pest management in aquatic systems, where the balance of aquatic organisms can significantly impact water quality and overall ecosystem health. It emphasizes an ecological approach to controlling unwanted species by leveraging existing biological interactions rather than relying solely on artificial substances.

The other choices highlight different concepts in ecological systems, such as physical influences on populations, synthetic chemical use for pest elimination, and the introduction of new species, which may have other ecological implications but do not capture the essence of biological control.