Last week molecular biologist Juan Ramirez-Lugo put all his coral samples in the freezer, locked the door of his lab, and told his six undergraduate assistants to stay home the next day. The assistant professor of biology at the University of Puerto Rico (UPR) in San Juan wasn’t happy about yet another disruption to his research on seasonal variations in how corals respond to thermal stress and his efforts to give undergraduates “authentic research experiences.” But he felt he had no choice.