Corals Grow by “Writing” Their Own Skeleton

Reefs rise like underwater cities, and at first they can look like piles of stone. In reality, every ridge is the result of tiny animals building patiently.\n\nCoral polyps create hard skeletons from minerals in seawater. Those skeletons grow layer by layer; as colonies expand, reefs spread like architecture adding new rooms.\n\nSurprising detail: reefs can be climate diaries, too. Skeleton layers can store clues about water temperature and chemistry—coral records the sea it lives in.\n\nThat’s why corals are key engineers of nature. Reef health shapes habitats for thousands of species and helps shield coasts from wave energy.