@ 1982, by the Amclican Society of Limnology and Oceanography, Inc. Acid precipitation: Its role in the alkalization of a lake in Michigan’

The watershed of Weber Lake in northern lower Michigan has experienced a nearly 20-fold increase in proton loading from acid precipitation in the past 25 years. But, owing to alkalinity production by biologically mediated processes (nitrate uptake by plants and sulfate reduction by bacteria) and increased rates of carbonate weathering, acid precipitation has doubled the- alkalinity, raised the equilibrium pH, and made this soft-water seepage lake Acid precipitation is a major environ-mental problem. Over the past 25 years the acidity of rain and snow falling on eastern North America and northern Eu-rope has increased markedly (see Liken