How can the agricultural runoff of fertilizers lead to the destruction of marine habitats?

Agricultural runoff containing fertilizers often leads to nutrient pollution in waterways, primarily nitrogen and phosphorus. When these nutrients enter marine environments, they can cause algal blooms, which deplete oxygen levels in the water and create "dead zones" where aquatic life cannot survive. This disruption of the ecosystem can result in the loss of biodiversity, harm to fish populations, and degradation of critical habitats such as coral reefs and seagrass beds. Ultimately, the imbalance created by excess nutrients can have devastating effects on marine health and productivity.