Subaerial
{{Short description|Term in geology and botany}}
In natural science, subaerial (literally "under the air") has been used since 1833,[http://www.merriam-webster.com/dictionary/subaerial Subaerial] in the Merriam-Webster dictionary. notably in geology and botany, to describe features and events occurring or formed on or near the Earth's land surface. They are thus exposed to Earth's atmosphere. This may be contrasted with subaqueousRobert L. Bates, Julia A. Jackson, Dictionary of Geological Terms AGI (1984) events or features located below a water surface, submarine events or features located below a sea surface, subterranean events or features located below ground, or subglacial events or features located below glacial ice such as ice sheets.
Geology
For example, a subaerial eruption of a volcano is one that ejects material in the open but "under the air" (under the atmosphere). Subaerial weathering is weathering by rain, frost, rivers etc.
The term "subaerial" may exclude processes occurring in caves. {{citation needed|date=February 2013}}
The term is often used in sedimentology.
Botany
Leaves are subaerial organs of plants.Macgregor Skene. [https://books.google.com/books?id=pdyHbU1aKfgC Biology of Flowering Plants], page 2. ed. Discovery Publishing House, New Delhi, reprinted in 2006. {{ISBN|81-7141-205-X}}.
Some plants may have subaerial roots, either totally (epiphytic plants such as some orchids) or more commonly only partly so. The oil palm tree can grow roots into accumulations of decaying leaves on the soil surface; these roots are said to be subaerial.R.H.V. Corley & P.B.H. Tinker. [https://books.google.com/books?id=NtCo1TdXuQkC The Oil Palm], 4th edition, page 37. Blackwell Science, 2003 (three eds. in 1967, 1977 and 1988). Epiphyte plants growing above ground that do not feed from their tree support (for example through their haustorium or feeding part having dug into the tree, such as Mistletoe)Macgregor Skene, [https://books.google.com/books?id=pdyHbU1aKfgC op. cit.], p. 229. have subaerial roots (for example some Ficus species).Macgregor Skene, [https://books.google.com/books?id=pdyHbU1aKfgC op. cit.], p. 71.
Subaerial stems are the stems that do not rise up but grow just above the ground. As a type of asexual propagation, these subaerial stolons, also called runners, often develop roots and leaves from their nodes.{{dead link|http://www.tutorvista.com/content/biology/biology-iii/angiosperm-morphology/subaerial-stem-modifications.php|date=April 2021}}"Subaerial Stem Modifications" on tutorvista.com.
Some pond plants have subaerial leaves as well as submerged leaves (water plantain, flowering rush).Macgregor Skene, op. cit., p. 294.
Subaerial algae are those that live on surfaces above the soil. The surfaces are diverse, and can either be natural (e.g. rocks, bark and leaves of trees, and hair of animals) or artificial (concrete, woodwork, and metal). When on artificial substrates, subaerial algae can be economically significant because they often lead to biodeterioration of the substrates.{{cite book|doi= 10.1007/978-1-4020-6112-7_33|chapter= The Systematics of Subaerial Algae|title= Algae and Cyanobacteria in Extreme Environments|series= Cellular Origin, Life in Extreme Habitats and Astrobiology|date= 2007|last1= Lopez-Bautista|first1= Juan M.|last2= Rindi|first2= Fabio|last3= Casamatta|first3= Dale|volume= 11|pages= 599–617|isbn= 978-1-4020-6111-0}}
See also
- Specialized root types
- Velamen – epidermis of subaerial roots in some orchids and other epiphytic plants