University of Southern Maine volunteers Tyler Cooke, 20, and Brittany Wood, 21, help pick up trash along Back Cove at low tide last Friday in Portland during USM’s second annual Day of Service.Sandra Wachholz, a criminology professor, helped organize the USM and Deering High School student volunteers. She said “it’s really the small stuff here that we tend to overlook, like these little plastic pieces. That’s the worst. These can kill animals.”