posted by y912f .
I need help on this question:
29. A common feature of thermal pollution and artificial eutrophication is that they both
a. have sources that are difficult to identify and control
b. cause large mats of algae to bloom in fresh water
c. are a result of power plants and other industrial activity
d. decrease the amount of oxygen dissolved in water
'...Eutrophication caused by humans is called artificial eutrophication. Fertilizer from farms, lawns, and gardens is the largest source of nutrients that cause artificial eutrophication. Phosphates in some laundry and dish washing detergents are another major cause of eutrophication. Phosphorus is a plant nutrient that can cause the excessive growth of algae. In bodies of water polluted by phosphorus, algae can form large floating mats, called algal blooms. As the algae die and decompose, most of the dissolved oxygen is used and fish and other organisms suffocate in the oxygen-depleted water.
...When the temperature of a body of water, such as a lake or stream increases, thermal pollution can result. thermal pollution can occur when power plants and other industries use water in their cooling systems and then discharge the warm water into a lake or river. thermal pollution can cause large fish kills if he discharged water is too warm for the fish to survive. But most thermal pollution is more subtle. If the temperature of a body of water rises even a few degrees, the amount of oxygen the water can hold decreases significantly. As oxygen level drop, aquatic organisms may suffocate and die. If the flow of warm water into a lake or stream is constant, it may cause the total disruption of an aquatic ecosystem.'
hold on, i think i got it. is it D?
the answer is in fact D =)