Exploring Coastal Ecosystems - Wednesday, April 13 - Dr. Greg Ruiz takes a North American Perspective on Biological Invasions in Coastal Ecosystems. Refreshments at 6:45pm; lecture at 7pm @ Smithsonian Environmental Research Center, 647 Contees Wharf Rd, Edgewater. free: 443-482-2400; www.serc.si.edu.