Eelgrass, underwater grasses found around the world, play a key role in storing so-called “blue carbon.” Seagrass habitats are in decline around the world, but the Comcaac people in northern Mexico have protected the grasses off the coast of their land near the Gulf of Mexico. A festival this month celebrated the plant and revived interest in the tradition of eating its nutritious seeds. Reporter Sam Schramski has the story.