In the article "Save the Coral Reefs," the author uses logos by providing scientific evidence that humans are destroying coral reefs. Logos is a rhetorical device in which an author provides concrete evidence and logical arguments as support for his position. This is a common persuasive device, and its purpose is to convince an audience of a particular position. In this case, the use of scientific evidence and logical statements support the argument the author makes: the fact that humans are destroying coral reefs.