Hermatypic

Hermatypic refers to reef-building stony corals, primarily in the order Scleractinia, that secrete calcium carbonate skeletons. They host symbiotic dinoflagellate algae (zooxanthellae) in their tissues, which photosynthesize and provide much of the coral’s energy. This mutualistic relationship supports rapid growth and substantial sediment production.

Most hermatypic corals inhabit shallow, sunlit tropical and subtropical seas, typically at depths up to about 50 meters, in clear, warm waters with stable salinity and moderate nutrients. They form extensive reef structures where environmental conditions are suitable, creating complex habitats for many other marine species.

Ecologically, hermatypic corals contribute to reef architecture through calcification and accumulation of reef material. They reproduce both sexually and asexually, with many species engaging in mass spawning events that enhance dispersal and genetic mixing, helping reefs recover after disturbances.

Ahermatypic corals are those that do not contribute significantly to reef formation. Many are azooxanthellate (lacking symbiotic algae) and occur at greater depths or in low-light environments, where reef-building is not favored.

Threats to hermatypic corals include climate-related stressors such as ocean warming and acidification, which reduce calcification and trigger bleaching when zooxanthellae are expelled. Local pressures—pollution, overfishing, and destructive coastal development—also threaten reef systems. Conservation efforts focus on protecting reef habitats, reducing local stressors, and addressing broader climate change impacts.