How do giant clams benefit from symbiotic algae?

Giant clams (family Tridacnidae) maintain a mutually beneficial symbiotic relationship with zooxanthellae, which are minute algal cells housed within the clam's mantle tissue.

The giant clam benefits from this partnership by gaining access to essential nutrients. Specifically, the clam derives nutritional value from either the metabolic products produced by the algae or from the digestion of the algae themselves when they are culled. In exchange, the algae benefit by having access to the dissolved waste products produced by the clam, which they can utilize for their own growth and survival.1