''Hydropunctaria maura'' (still often called by the older name ''Verrucaria maura'') is a species of saxicolous (rock-dwelling),

crustose lichen Crustose lichens are lichens that form a crust which strongly adheres to the Substrate (biology), substrate (soil, rock, tree bark, etc.), making separation from the substrate impossible without destruction. The basic structure of crustose lichen ...

belonging to the family

Verrucariaceae The Verrucariaceae are a family of mostly lichenised fungi in the order Verrucariales. The lichen-forming species, which comprise the vast majority of the family, have a wide variety of thallus forms, and include crustose (crust-like), foliose ( ...

. A perennial species that does not experience seasonal variations, it is the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

of the genus ''Hydropunctaria''. The medulla is a black basal layer that forms columns (

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

: ''punctae'') to the upper surface and isolates the algae into pockets near the upper surface. The black band formed by ''H. maura'' can often be seen at a distance as a marker of the high water point.

Ecology

''Hydropunctaria maura'' is commonly found on hard rocks in the

intertidal zone The intertidal zone, also known as the foreshore, is the area above water level at low tide and underwater at high tide (in other words, the area within the tidal range). This area can include several types of habitats with various species o ...

. Compared to terrestrial lichens, the species is typically located in areas of direct sunlight, suggests that it may have specific adaptations against damage from the sun. It is considered an upper

littoral The littoral zone or nearshore is the part of a sea, lake, or river that is close to the shore. In coastal ecology, the littoral zone includes the intertidal zone extending from the high water mark (which is rarely inundated), to coastal areas ...

(supralittoral) lichen, compared to other, lower littoral lichens such as ''

Wahlenbergiella mucosa ''Wahlenbergiella mucosa'' is a species of saxicolous (rock-dwelling), crustose lichen in the family Verrucariaceae. It is a marine species that grows in the littoral zone, and therefore remains immersed in seawater for extended periods. Its phot ...

'', distinguished by environmental factors such as water availability, UV exposure, and temperature. Because of the relatively extreme conditions of the supralittoral zone, crustose lichens are the only organisms capable of colonizing these areas. ''H. maura'' effectively serves as the primary biological indicator of the extent of the zone where it is found. Both ''H. maura'' and '' Hydropunctaria amphibia'' synthesize

sucrose Sucrose, a disaccharide, is a sugar composed of glucose and fructose subunits. It is produced naturally in plants and is the main constituent of white sugar. It has the molecular formula . For human consumption, sucrose is extracted and refined ...

in response to high salt concentrations. It forms thin, matte-black crusts with the algae genus '' Dilabifilum'' as a

photobiont A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.thalli Thallus (plural: thalli), from Latinized Greek (), meaning "a green shoot" or "twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. Many of these organisms were ...

, and a higher number of different bacterial sequences. The diversity of microorganisms is likely related to its strong marine influence. It is commonly associated with ''

Thermoproteota The Thermoproteota (also known as crenarchaea) are archaea that have been classified as a phylum of the Archaea domain. Initially, the Thermoproteota were thought to be sulfur-dependent extremophiles but recent studies have identified characteris ...

'' (formerly ''Crenarchaeota''). Other studies have identified '' Jannaschia pohangensis'' and ''

Bacillus aerius ''Bacillus aerius'' is a species of bacteria first isolated from cryogenic tubes used for collecting air samples from high altitudes, hence its name. Its type strain is 24KT (=MTCC 7303T =JCM 13348T). References Further reading * * * * Extern ...

'', among others, as associated with ''Hydropunctaria maura''. The growth rate of ''H. maura''

colonies In modern parlance, a colony is a territory subject to a form of foreign rule. Though dominated by the foreign colonizers, colonies remain separate from the administration of the original country of the colonizers, the '' metropolitan state'' ...

is estimated to be less than 1 mm per year. After elimination, it is estimated to take three years for the species to recolonize a substrate.

Germination Germination is the process by which an organism grows from a seed or spore. The term is applied to the sprouting of a seedling from a seed of an angiosperm or gymnosperm, the growth of a sporeling from a spore, such as the spores of fungi, fer ...

of the spores of this species is stimulated by seawater

salinity Salinity () is the saltiness or amount of salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensionless and equal ...

concentrations that typically inhibit germination of spores of other lichens.

Distribution

''Hydropunctaria maura'' is one of the most widespread and abundant lichens in the European littoral zone, and has been found around the world, in extreme climes such as the Arctic and Antarctica. It has a

cosmopolitan distribution In biogeography, cosmopolitan distribution is the term for the range of a taxon that extends across all or most of the world in appropriate habitats. Such a taxon, usually a species, is said to exhibit cosmopolitanism or cosmopolitism. The ext ...

, and is found on both the East and West coasts of North America, and in the Southern Hemisphere in Tasmania and New Zealand. The cyanolichen ''

Lichina confinis ''Lichina'' is a genus of lichens in the family Lichinaceae. The genus contains seven species. These cyanolichens include maritime species such as '' L. pygmaea'' or '' L. confinis'', in which the associated cyanobiont has been assigned ...

'' is often found in the same zone as ''Hydropunctaria maura''.

References

{{Taxonbar , from=Q10660740 Verrucariales Lichen species Lichens of the Arctic Lichens described in 1803 Cosmopolitan species