Acid Deposition and Oxidant Research Center
Asia Center for AirPollution Research(ACAP)
Global environmental
Mechanism of acid deposition
Impacts of acid deposition
pH of rain
Energy consumption and acid deposition
Consumption of natural resources and acid deposition
Research Activity
e-learning course

3. Impacts of acid deposition

There are many living creatures in natural ecosystems like lakes and forests. How does acid deposition affect them ?

There are many living creatures in natural ecosystems like lakes and forests. How does acid deposition affect them ?

Impacts on fish
After rivers and lakes became acidic in Scandinavian countries, various fish species, including Atlantic Salmon and brown trout, disappeared. In the very cold winters common in Scandinavian and Northern American countries, snow with acidic substances fall in winter, and rapidly melt in spring to make rivers and lakes acidic. Salmon spawn in autumn and fry live for about half a year until spring in the rivers where they are born. Since Salmon have weak tolerance for acidity, they can not survive the snow melting seasons.

Impact on fish

Tovdal River in Norway where salmons died. (Provided by Dr. Kenichi Satake)

Spawning of kokanees
Recent Japanese research disclosed the response of kokanees, a kind of salmon, to acidity. Kokanees are very sensitive to acidity in water and stop spawning at the slightest lowering of pH (changes from pH 7 to pH 6). Although we had thought that there would be much less impacts by pH changes around pH 7, kokanees were significantly affected. Other research shows that aluminum ion, easy to dissolve in acidic water, also significantly affects fish.

Kokanees Spawning of Kokanees
Courtship behavior of Kokanees
(Provided by Dr. Syoji Kitamura)
Spawning of Kokanees
iProvided by Dr. Syoji Kitamuraj

Impacts on living creatures other than fish
It is known that insects and shellfish, the food of fish, are affected when rivers and lakes become acidic. Acidity also affects plants in water. Several types of plant plankton change with changes of acidity, while certain bacteria and fungi (molds etc.) are more tolerable than others.

Impacts on forests
Acid deposition affects soil, water, various living creatures, and plants as well. For example, high sulfur content coal from the Black Triangle, near the borders of Germany, Czech and Poland, was a significant resource for power plants and factories. The industrial processes lead to significant emissions of sulfur dioxide, and resulted in many dead forests. Similar phenomena have been observed in Chonqing, China.

Sulfur dioxide is emitted in refining metals such as copper and nickel, which also contain high levels of sulfur. In the past, forests died in Ashio, Japan due to the high concentration of sulfur dioxide generated from copper refining. Even now, we have similar damage at various sites in the world. For example, we can observe tens of kilometers of dead forests around the metal refining factories at Kora Peninsula in the western part of Russia.

Indirect impacts of acid deposition include increased damage by a fungus called Naratake. Naratake rapidly grows in acidic soil and invades plants, leading to withering.

We have many cryptomeria plantations in Japan. Cryptomeria has strong tolerance for soil acidity, but acid deposition has changed the nutritional balance in the soil, and is affecting growth of cryptomeria in some parts of Japan.

Dead forests in Krusne hory mountains, Czech Republic
(Provided by Dr. Kenichi SATAKE)

Impacts on buildings
Have you seen what appears to be icicles on walls and eaves of old buildings and highways ? Dirty raindrops go into walls through cracks, dissolve calcium in concrete materials, and then leach out of walls. They combine with carbon dioxide in the air and formulate calcium carbonate, which grows like icicles. When we observe these "icicles", we can find dirty droplets at the top of the "icicles".

Acid rain dissolves not only concrete materials but also marble floors and sculptures, and even copper roofs and sculptures. If acid deposition continues, we will have wider damage and our environment will significantly change.

Bronze statue rusted like a stream
(Proveded by Mr. Takeo KADOKURA)

Icicles hanging from the eaves
(Provided by Mr. Takeo KADOKURA)


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