scenario: A company puts hot wastewater back into a river, increasing
the overall temperature of the river by a few degrees. The waters
temperature is now too high for certain plants to survive. The plants
that once provided food and important habitat for fish are now gone.
The fish population leaves or dies off. Larger mammals that fed
on those fish are forced to move on to other areas to find food.
So a seemingly small change in water quality, a slight rise in temperature,
set off a devastating chain reaction.