How can agricultural runoff affect aquatic ecosystems?

Agricultural runoff significantly impacts aquatic ecosystems by introducing excess nutrients, such as nitrogen and phosphorus, as well as various chemicals, including pesticides and fertilizers, into water bodies. When these inputs occur, they can lead to nutrient pollution, which can result in harmful algal blooms. These blooms can deplete oxygen levels in the water when they die and decompose, creating hypoxic conditions that can be detrimental to fish and other aquatic organisms.

Moreover, the introduction of pesticides and other chemicals can be toxic to aquatic life, disrupting reproductive and developmental processes and leading to declines in populations of sensitive species. The combination of these effects ultimately alters the balance of the ecosystem, potentially leading to decreased biodiversity and the degradation of water quality.

Understanding this process is critical for managing agricultural practices to mitigate their impact on nearby lakes, rivers, and streams, and for preserving the health of aquatic ecosystems.