ulties the fish's reproductive system. Often fish born in acid lakes do not survive for they are born with birth defects such as twisted and deformed spinal columns. This is a sign that they are unable to extract enough calcium from the water to fully develop their bone. These young soon die. With no competition the older,stronger can grow easily. However there food is contaminated as well by the acid in the water. Soon they have not enough food for themselves and turn to cannibalism. With only an older population left there is no one left to regenerate themselves. Soon the lake dies. By the late 1970s many Norwegian scientists began to suspect that it was not only the acid in the water that was causing the deaths. They had proved that most fish could survive in a stream that had up to a 1 unit difference in PH. After many experiments and research they found that their missing link was aluminum. Aluminum is one of the most common metals on earth. It is stored in a combined form with other elements in the earth. When it is combined it cannot dissolve into the water and harm the fish and plants. However the acid from acid rain can easily dissolve the bond between these elements. The Aluminum is then dissolved into a more soluble state by the acid. Other metals such as Copper (Cu), iron (Fe) etc can cause such effects upon the fish as well however it is the aluminum that is the most common. For example: CuO + H2SO4 ----------* CuSO4 + H2O In this form it is easily absorbed into the water. When it comes in contact with fish it causes irritation to the gills. In response the fish creates a film of mucus in the gills to stop this irritation until the irritant is gone. However the aluminum does not go always and the fish continues to build up more and more mucus to counteract it. Eventually there is so much mucus that it clogs the gills. When this happens the fish can no longer breath. It dies and then sinks to the bottom of the ...
