Tropical coral reefs are vibrant underwater ecosystems found in warm, shallow ocean waters near the equator. They are primarily built by tiny marine animals called coral polyps, which secrete calcium carbonate to form hard structures. These reefs support a diverse range of marine life, including fish, mollusks, and sea turtles, making them one of the most biodiverse ecosystems on the planet. Coral reefs provide essential benefits to humans, such as protecting coastlines from erosion and supporting fishing industries. They also play a crucial role in carbon cycling and serve as important sites for scientific research. However, they face threats from climate change, pollution, and overfishing, which can lead to coral bleaching and habitat loss.