<P> Coralline algae are red algae in the order Corallinales . They are characterized by a thallus that is hard because of calcareous deposits contained within the cell walls . The colors of these algae are most typically pink , or some other shade of red , but other species can be purple , yellow , blue , white or gray - green . Coralline algae play an important role in the ecology of coral reefs . Sea urchins , parrot fish , and limpets and chitons ( both mollusks ) feed on coralline algae . In the temperate Mediterranean sea , coralline algae are the main builders of a typical algal reef , the Coralligène ( `` coralligenous '' ) . Many are typically encrusting and rock - like , found in marine waters all over the world . Only one species lives in freshwater . Unattached specimens ( maerl , rhodoliths ) may form relatively smooth compact balls to warty or fruticose thalli . </P>
<P> Coralline algae are red algae in the order Corallinales . They are characterized by a thallus that is hard because of calcareous deposits contained within the cell walls . The colors of these algae are most typically pink , or some other shade of red , but other species can be purple , yellow , blue , white or gray - green . Coralline algae play an important role in the ecology of coral reefs . Sea urchins , parrot fish , and limpets and chitons ( both mollusks ) feed on coralline algae . In the temperate Mediterranean sea , coralline algae are the main builders of a typical algal reef , the Coralligène ( `` coralligenous '' ) . Many are typically encrusting and rock - like , found in marine waters all over the world . Only one species lives in freshwater . Unattached specimens ( maerl , rhodoliths ) may form relatively smooth compact balls to warty or fruticose thalli . </P>
what is the name of the small red macroalgae that develop a hard crust
what is the name of the small red macroalgae that develop a hard crust
Coralline algae
Coralline algae