John Eaton will give a slide-talk entitled: Beneath the surface: The health of Maine’s Midcoast estuaries in the age of ocean acidification Eaton of Georges River Tidewater Association will speak on the early results of a long-term citizen monitoring survey designed to monitor the health of the St. George, Medomak and Weskeag River estuaries. Rockland Public Library, Union St.. Admission is free.