A new previously unknown life-stage of stony coral larvae has been published describing how a small percentage of lab-grown coral planula can float through metamorphosis. That was not a euphimism, as some stony coral larvae have been documented secreting a buyoant skeleton that causes the planula to develop into unsettled, floating spats, or single corallites.
While working with the larvae of several coral species including Montipora capitata, Acropora palmata, Agaricia humilis, Montastea cavernosa and M. faveolata, Dr. Mark Vermeij has repeatedly documented a small subset of the larvae metamorphosing while still floating at the surface. Between three and seven percent of Dr. Vermeij’s coral larvae develop into fully fledged little corallites with zooxanthellae growing in the aboral surface of the corallite which would normally have grown onto a reef structure.
The phenomenon of floating corallites has so far only been documented in the lab and some of the floating coral polyps did eventually detach from their floating corallites, and settled to the bottom with a new, heavy skeleton. The documentation of floating corallites by Dr. vermeij opens up a whole new world of possibilities for how coral species have spread throughout the seas since the floating corallites can ride ocean currents for much longer than the planula stage alone. [Coral Reefs]