Nature’s tiny engineers
Conventional wisdom has long held that corals — whose calcium-carbonate skeletons form the foundation of coral reefs — are passive organisms that rely entirely on ocean currents to deliver dissolved substances, such as nutrients and oxygen. But now scientists at MIT and the Weizmann Institute of Science (WIS) in Israel have found that they are far from passive, engineering their environment to sweep water into turbulent patterns that greatly enhance their ability to exchange nutrients and dissolved gases with their environment. “These microenvironmental processes are not only important, but also unexpected,” says Roman Stocker, an associate professor of civil and environmental engineering at MIT and senior author of a paper describing the results in the Proceedings of the National Academy of Sciences. When the team set up their experiment with living coral in tanks in the lab, “I was expecting that this would be a smooth microworld, there would be not much...