Volunteers collect water samples and take quality measurements in the Tijuana River Estuary.
PHOTO CREDIT: Tijuana River National River Estuarine Research Reserve

Ben Mack prepares to take a water sample at the Cheat Dam near Mt. Morris, Pa.
PHOTO CREDIT: West Virginia University

David Flores drives while Debra Lenik prepares to sample water from Baltimore Harbor.
PHOTO CREDIT: Shan Gordon