What is the impact of agricultural runoff on aquatic ecosystems?

Agricultural runoff has a significant impact on aquatic ecosystems, primarily by introducing excess nutrients and pollutants into water bodies. This results in eutrophication, a process where nutrient overload, particularly nitrogen and phosphorus, stimulates excessive growth of algae and aquatic plants.

As algae proliferate, they can form harmful algal blooms that deplete oxygen in the water and block sunlight from reaching other aquatic organisms. When these algae die and decompose, the resulting decay further consumes oxygen, leading to hypoxic conditions that can cause fish kills and disrupt the entire aquatic food web. This shift changes the biological characteristics of the water, negatively affecting biodiversity, fish populations, and overall ecosystem health.

Moreover, the pollutants present in agricultural runoff, such as pesticides, heavy metals, and pathogens, can further harm aquatic organisms and complicate water quality issues. Therefore, the introduction of excess nutrients and pollutants is a critical issue concerning agricultural runoff and its detrimental effects on aquatic ecosystems.