This knowledge guides our practical decisions and becomes more valuable as we keep learning more. DNR staff has participated in hundreds of research projects that helped build this knowledge base. As part of the law, the utilities funded a 10-year research program to evaluate the effects of reducing those emissions. We've learned that lakes are protected from acidification by chemical buffers naturally supplied by streams and groundwater. Many lakes in northern Wisconsin are especially vulnerable to acid rain because nearly all of their water is supplied directly by rain and snow.
Acid rain affects aquatic organisms in complex ways.
In an intensive whole-lake experiment, we found that acidification hurts some aquatic organisms by changing their food source or habitat rather than by direct toxic effects of increased acidity. Acidity of both precipitation and lakes has reduced substantially since the mid-1980's. In some cases fish are successfully reproducing in these lakes for the first time in many years. So far, acidity levels are still decreasing, which suggests that acid-rain control legislation continues to benefit sensitive aquatic resources in Wisconsin. Wisconsin DNR took the lead in adapting ultra-clean sampling techniques for freshwater ecosystems.