Brain Coral (IMAGE) Penn State Caption Colony of the symmetrical brain coral, <i>Pseudodiploria strigosa</i>, that is a common reef-building coral in the Caribbean. When under stress, these animals may harbor a species of mutualistic microbe, which was recently discovered to be introduced from the Indo-Pacific. This microscopic symbiont, a dinoflagellate, increases the stress tolerance of native corals, but may significantly reduce the animal's rate of calcification, thus diminishing their role as reef builders. Credit Robin T. Smith, Science Under Sail; Sung Yeon Lee and Hae Jin Jeong, Seoul National University Usage Restrictions Non commercial use only License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.