Which term describes the excessive or dense growth of algae?

The term that describes the excessive or dense growth of algae is "algal bloom." Algal blooms occur when environmental conditions, such as nutrient enrichment from runoff (particularly nitrogen and phosphorus) and favorable temperatures, create an environment conducive to rapid algal growth. These blooms can result in a thick layer of algae on the surface of water bodies, which can block sunlight needed by other aquatic plants and disrupt the ecosystem.

Algal blooms can also lead to harmful consequences, such as oxygen depletion when the algae die and decompose, potentially harming fish and other aquatic life. Notably, some algal blooms produce toxins that can be detrimental to both aquatic organisms and human health. Understanding the dynamics of algal blooms is essential for managing aquatic environments and maintaining water quality.