On May 5, 2014 NASA’s Terra satellite flew over the Atlantic Ocean, allowing the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard to capture this true-color image of the jewel-like ‘island’ of Bermuda.
Although usually thought of as a single island, this overseas territory of the United Kingdom is actually an archipelago of more than 100 islands, packed in an area of about 1/3 the size of Washington, DC and edged in sparkling beaches – some of which glow pink. The pinkness of the beaches are the result of the red colors found in organisms in offshore reef formations, and in invertebrates such as clams and other shells found in the surrounding ocean. When organisms with red in the skeleton or shell die, fall to the ocean floor, and are ground over time into tiny grains, they become material for building beaches, waiting only for the restless tide to bring them ashore.
The circular shape formed by the islands and the associated underwater coral reefs (which appear brilliant blue in this image) is the outline of an ancient volcanic caldera. After the formation of the volcanic ridge, calcite-secreting marine organisms settled on it, building the coral reef. Eventually the reef became so large that the skeletons of the organisms formed a limestone cap. During the Pleistocene, the sea level fell as the Ice Age matured, and the limestone cap poked upward, then began to break into sand, then eventually to sandstone. Islands formed in this manner are called atolls. Bermuda is the only atoll in the Atlantic Ocean.