Northern Star Coral
This small coral is found from the Caribbean to as far north as Woods Hole, and also on the west coast of Africa. It grows in clumps on hard surfaces, like rocks, piers, and oyster shells, but does not form reefs. Like almost all corals, northern star coral houses symbiotic microorganisms called zooxanthellae inside its body. In return for this protection, these tiny creatures provide the coral with nutrients. They’re also responsible for its color.
Many corals kick out their zooxanthellae during stressful events like an increase in water temperature and can die if adverse conditions continue—this is known as coral bleaching and is one of the reasons corals are at risk from climate change. Northern star coral, however, thrives even after bleaching.
Cape Cod’s only native shallow-water hard coral, Astrangia poculata is studied by MBL scientists to better understand the role of symbionts and temperature in coral skeleton formation. Researchers in the MBL’s Roberson Lab are also interested in how these corals can withstand a wide range of temperatures when most tropical corals are stressed by only a few degrees temperature change. Because of their clear tissues, they are also used to image critical events like bleaching to elucidate the actual mechanism of the process as well as associated changes in physiology or biochemistry.