How can waterfowl negatively impact water quality?

Waterfowl can negatively impact water quality primarily through the accumulation of droppings in the water, which can lead to nutrient loading. When waterfowl excrete waste in or near water bodies, their droppings contain high levels of nitrogen and phosphorus. While these nutrients may initially seem beneficial for plant growth, excessive amounts can cause phenomena such as algal blooms. These blooms can deplete oxygen in the water, creating dead zones and harming aquatic life. Additionally, the decaying algal matter contributes further to oxygen depletion, which can have detrimental effects on fish and other aquatic organisms.

While competition with fish for food and physical disruption of aquatic vegetation are important aspects of the dynamics between waterfowl and aquatic ecosystems, the direct impact of nutrient overload from droppings is a more significant and immediate concern regarding water quality. The reduction of sedimentation is not typically a role of waterfowl; instead, they may contribute to sediment disturbance through their activities.