What does the term 'eutrophication' refer to?

The term 'eutrophication' refers specifically to the process by which water bodies receive an excess of nutrients, primarily nitrogen and phosphorus. This nutrient enrichment leads to a significant increase in the growth of algae, a phenomenon known as algal blooms. These blooms can deplete the oxygen in the water, leading to hypoxic conditions that can harm aquatic life, disrupt ecosystems, and cause dead zones where most marine life cannot survive.

Understanding eutrophication is crucial from an ecological perspective since it demonstrates how nutrient runoff—often from agricultural activities and urban runoff—can accelerate growth in aquatic plants, ultimately leading to problems in water quality and aquatic habitats. While the other options touch on water-related issues, they do not accurately define eutrophication, which distinctly focuses on the nutrient enrichment and its consequences on freshwater systems.