What are the major components of a healthy aquatic ecosystem?

A healthy aquatic ecosystem is characterized by several key components that contribute to its overall functionality and biodiversity. Water quality is fundamental, as it affects the health of all organisms living in that ecosystem; it includes parameters such as pH, dissolved oxygen, and the presence of pollutants. Aquatic plants play a critical role in providing habitat and food for various organisms, contributing to the overall productivity of the ecosystem. They also help stabilize sediments and improve water quality through processes like photosynthesis. Fish are vital members of these ecosystems, serving as both predators and prey, thus maintaining the balance of populations within the food web.

The other choices include factors that, while important in specific contexts, do not comprehensively define a healthy aquatic ecosystem. Salinity and temperature are vital in aquatic environments, especially in specific types of ecosystems like estuaries or marine environments, but they alone do not encompass the full range of necessary components. Leaf litter and soil types pertain more closely to terrestrial ecosystems rather than being fundamental elements of aquatic habitats. Focusing exclusively on fish and invertebrates overlooks the essential roles of plants, water quality, and the interactions among various organisms that contribute to the system's health.