Nutrients, predation and the history of reef-building

The trophic structure of modern tropical benthic communities, especially reefs, is profoundly influenced by ambient nutrient levels and resultant predator characteristics. In oligotrophic regimes the presence of abundant specialist grazers promotes succession and yields climax-stage communities. Such communities produce the classic «framework» reef dominated by large, heavily calcified phototrophs and multiserial mixotrophs. These primary producers bear many anti-predator adaptations and have a marked preference for hard-substrates. Increasing nutrient levels favor a transition in the benthos from photo- and mixotrophs via benthic algae to soft-substrate communities of solitary or uniserial heterotrophs feeding on planktonic primary producers