MORPHOLOGICAL PLASTICITY IN A GORGONIAN CORAL (BRIAREUM-ASBESTINUM) OVER A DEPTH CLINE

We document pronounced variation in whole colony morphology as well as polyp density, sclerite morphology, egg size, and egg number between colonies of Briareum asbestinum (Gorgonacea) from shallow and deep ree fs. Colonies from shallow (5 m) sites are shorter and stouter than col onies from deep (35 m) sites, with a greater density of polyps, greate r number of eggs per polyp, and larger eggs than their deep counterpar ts; in addition, deep colonies contain longer sclerites than shallow c olonies. Through a transplant experiment, we demonstrate that variatio n in morphology of colonies and sclerites between shallow and deep ree fs is due, in part, to environmental effects. The stout colonies of sh allow reefs become thinner in deeper water and develop longer sclerite s and fewer polyps. Deep-water colonies become stouter and develop mor e polyps when moved to shallow water. The shifts in sclerite morpholog y may have consequences for resistance to predation. Cyphoma gibbosum (Gastropoda) avoids artificial foods invested with deep water relative to shallow water sclerites.