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. 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.