What triggers algal growth in aquatic ecosystems?

Nutrient runoff from the land is a primary driver of algal growth in aquatic ecosystems. When rainfall or irrigation occurs, fertilizers and other nutrients such as nitrogen and phosphorus can be washed from agricultural fields into nearby streams, rivers, and lakes. These nutrients serve as food for algae, leading to their rapid growth, a process known as eutrophication.

This excessive algal growth can deplete oxygen levels in the water as the algae decompose, which may harm aquatic life and disrupt the overall ecosystem balance. Therefore, the introduction of excess nutrients from agricultural runoff is crucial to understanding why algal blooms occur and how they can impact aquatic environments. Managing nutrient inputs is vital for maintaining water quality and ecological health in these systems.

In contrast, a reduction in water temperature or increases in sedimentation and turbidity can influence algal growth, but they are not the primary triggers. Additionally, while the decline of essential aquatic microorganisms can affect ecosystem dynamics, it does not directly cause algal blooms. Understanding these connections is critical for effective management in agriculture and aquatic systems.