But researchers suspect that the decline is a result of years of acid rain leaching these compounds out of the soil at a faster rate than they are replaced. A major source of base cations is the breakdown of rocks in soil. Researchers also say climate may affect levels of base cations. This is an overwhelming conclusion. We can't just make a policy implementation and walk away and assume that we've fixed the problem.
Scientists say little is known about what, if any, biological recovery has occurred.
Testing water chemistry, they note, is much simpler and faster than accounting for changes in the presence or number of many different kinds of animals and plants. But the scientists who were interviewed agreed that biological recovery would be much longer in coming. Schindler said that in experimentally acidified lakes in which plants, fish, crustaceans and other life had disappeared, some species returned within days when the lakes were later allowed to recover, while others still have not returned after more than a decade. It may take a long time to recover from its effects.