Our knowledge of Lihou is limited to only a few islands and their shallow fringing reefs. The vast majority is inaccessible to human divers. Where sunlight starts to peter out, the familiar coral reefs are replaced by a deeper different world. We launched a survey by Remote Operated Vehicle or ROV, a type of robot, for the first ever human exploration of Lihou's deep reefs. Lihou's deep reefs are removed from the impact of cyclones and coral bleaching. But there is a more insidious threat. Like humans, deep reef building creatures must absorb calcium for their skeletons. For this to happen, the sea must be slightly alkaline. More and more carbon is dissolving in the ocean, making it more acidic. Soon, coral reefs, shelled animals, plankton, and other building blocks of life, may not be able to survive. Creatures like the nautilus, that have lived for 500 million years could cease to exist and remote places like Lihou could tragically change. This is our most profound consequence of a carbon lifestyle … it's in our power to stop, but only if we act now. Less