Question

some electric power plants use water pumped in from rivers to absorb the excess heat they produce. this warm water is then returned to the river. which of the following rows describes what can happen to the oxygen concentration and the variety of organisms at the point in the river where the warm water is returned? the presence of a species of large trout in a particular lake indicates a a. high dissolved oxygen concentration b. low dissolved oxygen concentration c. high water temperature d. low water ph

Explanation:

First Question (about river with warm water return)

1. Oxygen Concentration: As water temperature increases, the solubility of oxygen in water decreases. So when warm water (from power plants) is returned to the river, the oxygen concentration in that water will decrease (since warm water holds less dissolved oxygen).
2. Variety of Organisms: Most aquatic organisms are adapted to a certain temperature range and oxygen level. A decrease in oxygen (and a change in temperature) will stress or harm many species, leading to a decrease in the variety of organisms (as less species can survive in the altered conditions).

So the row where Oxygen Concentration decreases and Variety of Organisms decreases is Row C.

Large trout are typically sensitive to low oxygen levels and prefer cooler water. They require relatively high dissolved oxygen concentrations to survive (since they are often active, larger fish with higher metabolic demands). So the presence of large trout indicates a high dissolved oxygen concentration.

Answer:

C. Decreases, Decreases

Second Question (about large trout in a lake)