White Sand Beaches: You're Sunbathing on Fish Poop

The video explains how white sandy beaches are formed, focusing on the role of coral reefs and parrotfish. Coral reefs, made of polyps and aragonite, thrive in nutrient-poor waters with the help of symbiotic algae called zooxanthellae. Parrotfish contribute to beach sand by eating coral and excreting calcium carbonate as sand. The video concludes with credits and a call to support SciShow.

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