Record summer heat endangering coral reefs near Miami

Dangerous heat is increasing ocean temperatures, causing a crisis for coral reefs as some become diseased, bleached and withered. NBC News’ Sam Brock has more details on how experts are trying to save the endangered reefs. » Subscribe to NBC News: » Watch more NBC video: NBC News Digital is a collection of innovative and powerful news brands that deliver compelling, diverse and engaging news stories. NBC News Digital features , , , Nightly News, Meet the Press, Dateline, and the existing apps and digital extensions of these respective properties. We deliver the best in breaking news, live video coverage, original journalism and segments from your favorite NBC News Shows. Connect with NBC News Online! NBC News App: Breaking News Alerts: Visit : Find NBC News on Facebook: Follow NBC News on Twitter: Get more of NBC News delivered to your inbox: #NBCNews #HeatWave #ExtremeWeather