Acid Rain On Water
The effects of acid rain are most clearly seen in the aquatic, or
water,
environments, such as streams, lakes, and marshes. Acid rain flows to
streams,
lakes, and marshes after falling on forests, fields, buildings, and
roads. Acid
rain also falls directly on aquatic habitats. Most lakes and
streams have a pH
between 6 and 8. However, some lakes are naturally acidic
even without the
effects of acid rain. Lakes and streams become acidic (pH
value goes down) when
the water itself and its surrounding soil cannot buffer
the acid rain enough to
neutralize it. In areas like the Northeastern United
States where soil buffering
is poor, some lakes now have a pH value of less
than 5. One of the most acidic
lakes reported is Little Echo Pond in
Franklin, New York. Little Echo Pond has a
pH of 4.2. Lakes and streams in
the western United States are usually not
acidic. Because of differences in
emissions and wind patterns, levels of acid
deposition are generally lower in
the western United States than in the eastern
United States. This chart
shows that not all fish, shellfish, or their food
insects can tolerate the
same amount of acid: Generally, the young of most
species are more sensitive
than adults. Frogs may tolerate relatively high
levels of acidity, but if
they eat insects like the mayfly, they may be affected
because part of their
food supply may disappear. As lakes and streams become
more acidic, the
numbers and types of fish and other aquatic plants and animals
that live in
these waters decrease. Some types of plants and animals are able to
tolerate
acidic waters. Others, however, are acid-sensitive and will be lost as
the pH
declines. Some acid lakes have no fish. At pH 5, most fish eggs cannot
hatch.
At lower pH levels, some adult fish die. Toxic substances like aluminum
that
wash into the water from the soil may also kill fish. Together,
biological
organisms and the environment in which they live are called an
ecosystem. The
plants and animals living within an ecosystem are highly
interdependent. For
example, fish eat other fish and also other plants and
animals that live in the
lake or stream. If acid rain causes the loss of
acid-sensitive plants and
animals, then fish that rely on these organisms for
food may also be affected.