In the vastness of the ocean, there are many so-called animal to animal symbionts, seemingly odd-fellow relationships from which both species benefit. But what about symbiosis between an animal and a plant? Or more specifically, a plant-like alga called zooxanthellae?
It’s a surprisingly common phenomenom, especially in the shallows of warm equatorial reefs where there’s abundant light for photosynthesis. Take, for example, Tridacna gigas, the giant clam of the Indo-Pacific, the largest bivalve mollusk on Earth and the world's only sun-powered clam.