Have you ever explored along the ocean’s edge? Maine’s intertidal zone contains many more plants and animals than most people realize, and all have developed unique ways of coping with a harsh and shifting environment in which they are alternately submerged in salt water and exposed to the earth’s atmosphere. Chris Petersen, Ph.D., a marine biologist on the faculty at the College of the Atlantic in Bar Harbor, will present a program on life in the intertidal zone, including what we know and don’t know about the effects of invasive species, ocean acidification, and harvesting of species like rockweed on the ecology of the marine communities.