Question

how does cultural eutrophication affect aquatic ecosystems? it has no significant impact. it disrupts the balance of the ecosystem. it causes the water to get deeper. it improves biodiversity.

Explanation:

Cultural eutrophication is the process where human activities (like runoff of fertilizers) add excessive nutrients (especially nitrogen and phosphorus) to aquatic ecosystems. Excess nutrients cause rapid growth of algae (algal blooms). When these algae die, decomposition consumes oxygen (creating hypoxic or anoxic conditions). This harms fish, invertebrates, and other aquatic organisms. It also can lead to dominance of certain algal species over others, reducing biodiversity. So it disrupts the ecosystem balance. The option "It has no significant impact" is wrong as it clearly has major impacts. "It causes the water to get deeper" is incorrect as it doesn't affect water depth. "It improves biodiversity" is wrong as it usually reduces biodiversity due to species - specific impacts (e.g., some species thrive in low - oxygen conditions while others die).

Answer:

It disrupts the balance of the ecosystem.