Why is the runoff from fertilized agricultural fields, even if free of pesticides, often harmful to the ecosystems of temperate lakes?
A)Fertilizer compounds are toxic to fish.
B)The runoff causes heavy growth of algae, which eventually die and decompose, causing oxygen depletion.
C)Runoff water pools at the lake's bottom, where the fertilizer compounds react with materials in the sediment to form toxic substances.
D)The runoff is acid, and acidification kills key lake organisms.

Question

Quizplus · Accepted Answer

The runoff from fertilized agricultural fields contains excess nutrients, particularly nitrogen and phosphorus, which can lead to eutrophication in lakes. This means that there is an overgrowth of algae and other aquatic plants which eventually die and decompose, leading to a decrease in dissolved oxygen levels in the water. This reduction in oxygen can harm fish and other aquatic life, and often leads to the formation of "dead zones" in the lake.

Why Is the Runoff from Fertilized Agricultural Fields, Even If