Approximately how many coral species are recorded in Australia’s Great Barrier Reef?

About 600 coral species are recorded in Australia’s Great Barrier Reef.

This diversity includes reef-building hard corals as well as other coral groups. Hard corals create the calcium-carbonate framework that gives reefs their physical structure. Over long periods, the accumulated skeletons of successive coral generations form the foundations on which other organisms live.

The reef’s coral communities are not uniform. Different species thrive in different depths, water conditions and habitats, and the mix changes from the warmer northern region to the cooler southern region. Corals also live in partnership with microscopic algae called zooxanthellae, which provide much of their energy through photosynthesis.

The figure is an approximate species count rather than a claim that every survey will produce exactly the same total. Taxonomic research can revise species boundaries and records. Coral bleaching occurs when heat stress causes corals to expel their symbiotic algae; severe or prolonged bleaching can kill colonies, reducing habitat for fish and other reef life.