Coral reef researchers Carl Beaver and Hector Guittierez secure a rack of tiles to the exposed reef rock. Derek Hagman and Peter Vize, also of the University of Texas, collect coral gametes during the mass spawning event, allow them to be fertilized, and place them back on the reef in the hopes that the planula larvae will settle out onto the artificial substrate. This technique, if successful, could help in repopulation of damaged reef systems. (photo: Ed Enns)