The mailroom at the University of Washington’s School of Aquatic and Fishery Sciences looks pretty much like any other: rows of identical cubbies, each just a few inches tall, enough space to tuck a few letters inside. “And then there’s the COASST mailbox, and it’s like a foot and a half,” says Julia Parrish, executive director of the Coastal Observation and Seabird Survey Team, a community science project housed at UW. “We get more mail in a day, I would say, than the rest of the department put together.” The reason for all that mail is that COASST relies on more than a thousand residents of coastal communities from California to Alaska to look for dead seabirds and marine debris on shorelines in their communities, document their findings on paper data sheets provided by COASST, and send them in for Parrish and her colleagues to analyze. Participants help COASST scientists keep track of how natural and human-caused events like algal blooms, oil spills, and plastic...