Without primary production to support the rest of the food web, most of the communities beneaththe photic zone depend for food on or-ganic material produced in the surfacelayers of the ocean. Some of this surfaceproduction sinks into the dark watersbelow. Without a steady supply of foodfrom above, there could be little lifebelow the sunlit layer of the sea. The only known exception to this principle is dis-cussed in the section “Hot Springs, ColdSeeps, and Dead Bodies” (p.377)