Question

How can fertilizer use by farmers have negative effects on aquatic ecosystems?

Answer 1

It gives aquatic ecosystems a large amount of a limiting nutrient.

Explanation:

For example, if there was too much nitrogen and it is washed away by rain (called runoff), then the ecosystem would have too much nitrogen and would produce something called algal bloom. This is when algae float to the top of the water and stop all sunlight from entering, making it harder for autotrophs to produce food for themselves and its environment.