Most can tolerate only a certain range of temperatures.
Cold water can hold more DO than warm water.
Warm water, therefore, supports less life than cold water. Water used to cool the plant's reactors picks up the heat from the reactors, then is released into the waterways. Most aquatic life cannot tolerate such an increase in temperature. Here are some of the variables that affect a waterway's temperature. Color Most heat warming surface waters comes from the sun, so waterways with dark-colored water, or those with dark, muddy bottoms absorb heat best.