Editor’s Note: Editor’s Note: This story was identified by Paula Kahumbu, who is guest editor for CNN’s Call to Earth series. Famous for its sprawling nature reserves that are home to all “Big Five” ...

In 2019, scientists set out to map the extent of seagrass in Seychelles, an island nation off the eastern coast of Africa. There, they hit upon a startling number: More than 90% of the country’s “blue ...