PBS | 9:00 pm

In addition to being beautiful, coral reefs also are home to more than a quarter of all marine life, which makes them crucial to human societies around the globe as well. The new episode "Reef Rescue" examines how marine biologists are teaming up from around the world to counteract the catastrophic damage climate change is wreaking on these reefs due to warming ocean waters. Using a technique called assisted evolution, these scientists are trying to crossbreed heat-resistant corals and even transplant algae from healthy corals.