What can lead to phosphorus runoff into aquatic systems?

Phosphorus runoff into aquatic systems is significantly influenced by heavy rainfall. When heavy rainfall occurs, it can lead to the rapid movement of water across the land surface, which may wash away excess phosphorus that has accumulated in soil and on surfaces. This can include phosphorus from fertilizers used in agriculture, as well as from decomposed organic material. Once in the water, phosphorus can contribute to problems such as algal blooms, which can deplete oxygen in the water and harm aquatic life.

While other factors like plant uptake and soil compaction can play roles in the cycling and availability of phosphorus in ecosystems, they do not directly lead to runoff in the same way heavy rainfall does. Pest control, depending on the methods used, may not significantly influence phosphorus levels in aquatic systems. Therefore, heavy rainfall is the primary driver of phosphorus runoff into water bodies.