Question

A massive bluegill fish kill was observed in a lake near a power plant during the winter months. It was determined that the plant was releasing large amounts of hot water into the lake. Which of the following explains what likely caused the death of so many bluegills in the lake?
A: The increased water temperature caused dissolved oxygen levels to increase, leading to greater metabolic activity of catfish, which outcompeted the bluegill fish for resources.
B: The influx of warmer water caused an unexpected increase in the metabolic rate of the bluegills, which led to increased physiological stress from limited resource availability.
C: Rates of organic matter decomposition increased, which lead to an increase in dissolved oxygen and increased bacteria levels.
D: Photosynthetic output of aquatic plants decreased because of the higher temperature, which lowered the amount of carbon dioxide available for bluegills to carry out cellular respiration.

Answer 1

Answer:

Option B

Explanation:

Option D is incorrect, as increased photosynthesis would increase oxygen supply present, not carbon dioxide supply.

Option C is incorrect, as increased decomposition would increase carbon dioxide released and oxygen present is reduced, not increased.

Option A is unlikely as if this were the case, increased oxygen levels would enable bluegill fish to survive as well.