Montastraea cavernosa, Puerto Morelos, Mx. On my dives i like to show and explain to divers how reefs provide about the 70% of oxygen in the world. This photo shows how Polyps and Algae live together. Polyps extend their tentacles to get some floating plankton. Algae absorbs Uv light turning it into sugars and fats and Oxygen as a by product. The national park is working hard to keep this area as healthy as it can be by teaching divers and Tourist alike so we continue to enjoy this paradise!