If excessive amounts of hot water are discharged into a lake, the immediate result will most likely be:
A. an increase in the sewage content of the lake.
B. a decrease in the amount of phosphates in the lake.
C. an increase in the amount of PCB pollution in the lake.
D. a decrease in the amount of dissolved oxygen in the lake.
Discharging hot water into a lake is called thermal pollution. Besides the effect on the living organisms, warm water holds less oxygen than cool water.