When polyps die, they become hard, and new polyps grow on top of them. Gradually, over thousands of years, these layers form a coral reef. Polyps feed on other organisms, like plankton and algae.

Each polyp has a mouth surrounded by tentacles ... Together with coralline algae and other groups that produce limestone skeletons, corals gradually build up the complex three-dimensional structure of ...

In the coastal seas episode, we see the devastating scenes of coral bleaching – how whole reef ecosystems which once teamed with life, are now dead, white and derelict. But what exactly is coral ...

After surgery, the person may need to use a corticosteroid nasal spray to help prevent recurrence, although some polyps may grow back in a few years. Saline (saltwater) rinses help post-surgical ...

Each individual coral is a fragile ecosystem — a colony made up of thousands of tiny organisms called polyps. A coral reef is a teeming metropolis of mini-ecosystems built up over thousands of ...

Polyps grow slowly, forming different shapes and sizes depending on their species ... Among the biggest and best-known are the reef systems of the Great Barrier Reef of Australia, which is around ...