How does nutrient enrichment affect coral reefs?

Nutrient enrichment has a profound influence on coral reefs, primarily through its tendency to stimulate algal blooms. When excess nutrients, often from agricultural runoff or wastewater, enter the marine environment, they can lead to explosive growth of algae. These algal blooms can outcompete corals for space and light, and when they die and decompose, they can lead to further declines in water quality through the depletion of oxygen. This process can smother corals and hinder their ability to access the light needed for photosynthesis, ultimately leading to their decline and affecting the overall health of the reef ecosystem.

Other options suggest beneficial effects of nutrient enrichment, such as enhancing coral growth or promoting biodiversity, which do not align with the scientific understanding of the complex interactions within coral reef ecosystems. Coral species have evolved to thrive in oligotrophic (nutrient-poor) waters, and an overload of nutrients disrupts this balance, causing detrimental effects rather than promoting health or diversity.