Noticing large amounts of algal growth in her small farm pond,a farmer adds about 20 grass carp to feed on the abundant algae and plants.After several years,the carp grow large,exceeding 20 pounds each in size.Late one summer,the farmer notices that the carp and most of the other fish are dead.The water also smells very bad.Which one of the following is the most likely explanation for the death of these fish?

Question

Quizplus · Accepted Answer

The addition of the grass carp resulted in a large amount of feces and organic matter in the pond, providing a food source for bacteria which consume oxygen as they decompose it. Eventually, the bacteria use up all the available oxygen in the water, leading to a situation called hypoxia. Without oxygen, fish and other aquatic animals die, and decomposition of their bodies causes further oxygen depletion, making the situation worse. The bad smell also indicates the presence of anaerobic bacteria, which thrive in oxygen-depleted environments. Therefore, the most likely explanation for the death of the fish is that the bacteria feeding on the large volume of carp feces depleted the oxygen in the pond.

Noticing Large Amounts of Algal Growth in Her Small Farm