Divers can be the difference between a healthy reef and a tragedy. Teaming with biodiversity Coral reefs are a high-density location of biodiversity. This means that the variety of species living on a coral reef is greater than almost anywhere else in the world . Coral reef ecosystems are like bustling cities, with buildings made of coral and thousands of marine inhabitants coming and going, interacting with one another, carrying out their business. In this sense, coral reefs are cities under the sea .
Coral reefs provide shelter for nearly one quarter of all known marine species .
Over the last 350 million years, reefs have evolved into one of the largest and most complex ecosystems on the planet. Scientists estimate that, in total, more than 1 million species of plants and animals are associated with the coral reef ecosystem . The Coral Reef Alliance . All rights reserved.