Using a functional grouping approach is useful for understanding broader generalizations on the ecology of algae as well as predicting changes in algal community structure. Algal turfs consist mostly of tiny filaments with canopy heights of less than 10 mm. Crustose coralline algae play two important roles in the coral reef community, first by contributing calcium carbonate to reef structure and second by possibly facilitating settlement of coral recruits. The ecology of crustose corallines is complex often interrelated with the presence of macro and turf algae, grazing intensity by herbivores, and productivity. They are often able to recovery rapidly after being partially consumed by herbivores.
Turfs are capable of trapping ambient sediment and kill corals by gradual encroachment.
Most macroalgae possess some from of deterrent against herbivory, either through chemical deterrents or structural resistance. Although macroalgae are often more resistant to physical and biological disturbances than corallines and turfs, grazing by certain herbivores and high wave action can inhibit macroalgal growth. High macroalgal biomass can interfere with coral recruitment and reduce coral survival. Increased herbivory reduces algal biomass and shifts algal community dominance from macroalgae to turf algae and eventually to encrusting corallines. Corallines growing underneath a canopy of macroalgae are often different species and have a different morphology.