Crustose

A crustose lichen, Caloplaca marina

Crustose is a habit of some types of algae in which the plant grows tightly appressed to a substrate forming a biological layer of the adhering organism. Some species of marine algae of the Rhodophyta, in particular members of the order Corallinales, family Corallinaceae, subfamily Melobesioideae with cell walls containing calcium carbonate grow to great depths in the intertidal zone, forming crusts on various substrates.^[1] The substrate can be rocks throughout the intertidal zone, or, as in the case of the Corallinales, reef-building corals, and other living organisms including plants, such as mangroves and animals such as shelled molluscs. The corraline red algae are major members of coral reef communities, cementing the corals together with their crusts. Among the brown algae, the order Ralfsiales comprises two families of crustose algae.^[2]

Many lichens also grow close to the surface of rocks, tree trunks and other substrata, and are referred to as crustose lichens. Crustose organisms can be detrimental to engineered structures when found on buildings, coastal structures, and ships.^{[citation needed]}

References

1. ^ Lee, Robert Edward (2008). Phycology (4th ed.). Cambridge University Press. ISBN 9780521682770. 
2. ^ Lim, P.-E.; M. Sakaguchi; T. Hanyuda; K. Kogame; S.-M. Phang; & H. Kawai (2007). "Molecular phylogeny of crustose brown algae (Ralfsiales, Phaeophyceae) inferred from rbcL sequences resulting in the proposal for Neoralfsiaceae fam. nov.". Phycologia 46 (4): 456–466.