In the past two decades, the oyster population in Mississippi's Gulf waters has been devastated by both natural and manmade disasters. Among those working to restore oyster habitats is ninth grader Demi Johnson, who was recently recognized by the National Geographic Society for growing more than 1,000 oysters, which are likely to spawn millions more. John Yang speaks with Johnson about her work. PBS News is supported by - https://www.pbs.org/newshour/about/funders