An underwater ecosystem characterised by structure-building stony corals. Warm-water coral reefs occur in shallow seas, mostly in the tropics, with the corals  containing algae  that depend on light and relatively stable temperature conditions. Cold-water coral reefs occur throughout the world, mostly at water depths of 50-500 m. In both kinds of reef, living corals frequently grow on older, dead material, predominantly made of calcium carbonate . Both warm- and cold-water coral reefs support high biodiversity of fish and other groups, and are considered to be especially vulnerable to climate change.
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report