Nitrogen is used in many plant fertilizers. when it rains, the excess fertilizers run off into streams, rivers, and eventually are carried to the ocean. algae in the water feed off of the nitrogen in the fertilizers. the excess nutrients can cause a huge mat of algae to grow, called an algal bloom.

when the nitrogen is all used up, the algae die and decomposing bacteria begin to consume them. the bacteria multiply and consume most of the oxygen in the water, causing many of the fish and other larger organisms in the water to suffocate and die.

how could the problem of algal blooms be solved?
a.
the government should start a program in which they clean out all the algae from the lakes and streams before they become a problem.
b.
antibiotics should be added to the oceans to kill all of the bacteria before they can consume the dead algae.
c.
farmers and gardeners should use other methods to provide crops with the nitrogen they need.
d.
fish should be trained to swim to other parts of a body of water when the oxygen levels in one area become too low.