Written by the Fiveable Content Team • Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 exam•Written by the Fiveable Content Team • Last updated September 2025
Definition
Coral reefs are diverse underwater ecosystems formed by colonies of tiny animals called coral polyps. They thrive in warm, shallow waters with clear sunlight and provide habitat for numerous marine species.
Related terms
Bleaching: Coral bleaching occurs when corals expel their symbiotic algae due to stressors like increased water temperature or pollution. This leads to their white appearance and can result in coral death if prolonged.
Biodiversity Hotspot: Coral reefs are considered biodiversity hotspots due to their high species richness and endemism. They support an incredible array of marine life, including fish, crustaceans, mollusks, and many others.
Ocean acidification is the ongoing decrease in pH levels of seawater caused by increased absorption of carbon dioxide from human activities. It poses a threat to coral reefs as it inhibits their ability to build calcium carbonate structures necessary for growth.