What are some key biological indicators of a healthy aquatic ecosystem?

A healthy aquatic ecosystem can be assessed through various biological indicators that signify the overall health and stability of the environment. The diversity of aquatic plants and the presence of sensitive fish species are two critical indicators in this context.

The diversity of aquatic plants contributes to ecosystem resilience, providing habitat and food sources for a range of organisms. A wide variety of plant species can support a balanced community that nurtures both herbivores and predators, which in turn stabilizes the ecosystem. Similarly, the presence of sensitive fish species, which are often indicators of clean and clear water, reflects the quality of the aquatic environment. These species typically require specific habitat conditions and are less tolerant to pollution, thereby serving as early warning signs of ecological degradation.

In contrast, options that involve excessive growth of algae and reduced populations of predators indicate an imbalance, often due to nutrient overloads. High levels of pollution and nutrient loading disrupt the natural processes and ultimately harm aquatic life. A complete lack of any fish species suggests a severely degraded ecosystem that has lost its ability to support life. Therefore, while diversity and sensitive species signify health, the presence of imbalance and degradation indicates issues within the ecosystem.