There is more algae on coral reefs than ever before and humans are to blame. Can we use next generation techniques to play "Dr. Doolittle" and find out just how the coral animals feel about living in contact with algae? We know that some algae can kill coral in the lab, but we also know that algae and coral can grow next to each other on the reef seemingly unaffected. What hidden effect is algae having on coral? How will that impact the way we survey and manage coral reefs to preserve them?