Crustose is a habit of some types of

algae Algae ( , ; : alga ) are any of a large and diverse group of photosynthetic, eukaryotic organisms. The name is an informal term for a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from ...

and

lichens A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.appressed to a substrate, forming a biological layer. ''Crustose'' adheres very closely to the substrates at all points. ''Crustose'' is found on

rocks In geology, rock (or stone) is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its chemical composition, and the way in which it is formed. Rocks form the Earth's ...

and tree bark. Some species of marine

of the Rhodophyta, in particular members of the

order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...

Corallinales,

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Corallinaceae The Corallinaceae are one of the two extant Coralline families of red algae; they are differentiated from the morphologically similar Sporolithaceae by their formation of grouped sporangial chambers, clustered into sori. The Corallinoideae ...

, subfamily

Melobesioideae The Melobesioideae are a subfamily of Corallinacean Coralline algae with multiporate conceptacle Conceptacles are specialized cavities of marine and freshwater algae that contain the reproductive organs. They are situated in the receptacle and ...

with cell walls containing calcium carbonate grow to great depths in the intertidal zone, forming crusts on various substrates. The substrate can be rocks throughout the intertidal zone, or, as in the case of the Corallinales, reef-building

corals Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically form compact colonies of many identical individual polyps. Coral species include the important reef builders that inhabit tropical oceans and secre ...

, and other living organisms including plants, such as

mangrove A mangrove is a shrub or tree that grows in coastal saline or brackish water. The term is also used for tropical coastal vegetation consisting of such species. Mangroves are taxonomically diverse, as a result of convergent evolution in several ...

s and animals such as shelled molluscs. The coralline 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.

Growth and habitat

Many lichens 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. There are different types of Crustose lichens, including endolithic, endophloidic and leprose. Endolithic lichens are immersed in the outer layer of rocks with their bodies above the surface. Endophloidic ones are located in or on plant tissue. Leprose lichens consist of crusts without a layered structure. Crustose lichens have learned to adapt to their environment, with the shells helping with adaptation to dry and

drought A drought is defined as drier than normal conditions.Douville, H., K. Raghavan, J. Renwick, R.P. Allan, P.A. Arias, M. Barlow, R. Cerezo-Mota, A. Cherchi, T.Y. Gan, J. Gergis, D. Jiang, A. Khan, W. Pokam Mba, D. Rosenfeld, J. Tierney, an ...

resistant climates. Crustose lichens have been found in deserts, ice free parts of Antarctica, and in the Alpine and Arctic regions.

Characteristics

Crustose can come in a variety of colors such as yellow, orange, red, gray and green. These colors tend to be bright and vibrant. Crustose is similar to other lichens because they share a similar internal morphology. The lichen's body is formed from filaments of the fungal partner. The density of these filaments determines the layers within the lichen.

Productivity

There are many variations of crustose, including Crustose Coralline Algae (CCA), found in three different habitats; flat, crest and slope reef. CCA are highly dependent on sunlight to grow in abundance, and their growth increases productivity. CCA acts as the main food source for certain fish including parrotfish and Scarus trispinosus.

References

Red algae {{Biology-stub