Large group of multicellular algae, comprising the class Phaeophyceae
Brown algae
Temporal range: Late Jurassic to present 150–0 Ma[1][2]
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Ꞓ
O
S
D
C
P
T
J
K
Pg
N
Giant kelp (Macrocystis pyrifera)
Scientific classification
Domain:
Eukaryota
Clade:
Diaphoretickes
Clade:
SAR
Clade:
Stramenopiles
Phylum:
Gyrista
Subphylum:
Ochrophytina
Infraphylum:
Chrysista
Superclass:
Fucistia
Class:
Phaeophyceae Kjellman, 1891[3]
Orders
See classification
Synonyms
Fucophyceae Warming, 1884
Melanophyceae Rabenhorst, 1863
Phaeophyta
Brown algae (sg.: alga) are a large group of multicellular algae comprising the class Phaeophyceae. They include many seaweeds located in colder waters of the Northern Hemisphere. Brown algae are the major seaweeds of the temperate and polar regions. Many brown algae, such as members of the order Fucales, commonly grow along rocky seashores. Most brown algae live in marine environments, where they play an important role both as food and as a potential habitat. For instance, Macrocystis, a kelp of the order Laminariales, may reach 60 m (200 ft) in length and forms prominent underwater kelp forests that contain a high level of biodiversity.[4] Another example is Sargassum, which creates unique floating mats of seaweed in the tropical waters of the Sargasso Sea that serve as the habitats for many species. Some members of the class, such as kelps, are used by humans as food.
Between 1,500 and 2,000 species of brown algae are known worldwide.[5] Some species, such as Ascophyllum nodosum, have become subjects of extensive research in their own right due to their commercial importance. They also have environmental significance through carbon fixation.[4]
Brown algae belong to the Stramenopiles, a clade of eukaryotic organisms that are distinguished from green plants by having chloroplasts surrounded by four membranes, suggesting that they were acquired secondarily from a symbiotic relationship between a basal eukaryote and a red or green alga. Most brown algae contain the pigment fucoxanthin, which is responsible for the distinctive greenish-brown color that gives them their name. Brown algae are unique among Stramenopiles in developing into multicellular forms with differentiated tissues, but they reproduce by means of flagellated spores and gametes that closely resemble cells of single-celled Stramenopiles. Genetic studies show their closest relatives to be the yellow-green algae.
^Cite error: The named reference Medlin1997 was invoked but never defined (see the help page).
^Cite error: The named reference Lim1986 was invoked but never defined (see the help page).
^Kjellman, F. R. (1891). "Phaeophyceae (Fucoideae)". In Engler, A.; Prantl, K. (eds.). Die natürlichen Pflanzenfamilien. Vol. 1. Leipzig: Wilhelm Engelmann. pp. 176–192.
^ abCock, J. Mark; Peters, Akira F.; Coelho, Susana M. (9 August 2011). "Brown algae". Current Biology. 21 (15): R573–R575. doi:10.1016/j.cub.2011.05.006. PMID 21820616.
^Hoek, Christiaan; den Hoeck, Hoeck Van; Mann, David; Jahns, H.M. (1995). Algae: an introduction to phycology. Cambridge University Press. p. 166. ISBN 9780521316873. OCLC 443576944. Archived from the original on 16 October 2023. Retrieved 26 April 2018.
Brownalgae (sg.: alga) are a large group of multicellular algae comprising the class Phaeophyceae. They include many seaweeds located in colder waters...
Green algae are examples of algae that have primary chloroplasts derived from endosymbiotic cyanobacteria. Diatoms and brownalgae are examples of algae with...
chrysophytes, chrysomonads, golden-brownalgae or golden algae, are a large group of algae, found mostly in freshwater. Golden algae is also commonly used to refer...
color. But despite their name, red algae can vary greatly in color from bright green, soft pink, resembling brownalgae, to shades of red and purple, and...
belong to one of several groups of multicellular algae: the red algae, green algae, and brownalgae. Seaweeds are also harvested or cultivated for the...
apicomplexans, most ciliates, some green algae (the Klebsormidiales), choanoflagellates, oomycetes, brownalgae, yellow-green algae, Excavata (e.g., euglenids). Some...
diverse lineages of eukaryotes, containing ecologically important algae such as brownalgae and diatoms. They are classified either as phylum Ochrophyta or...
single-celled, but some are multicellular including some large seaweeds, the brownalgae. The group includes a variety of algal protists, heterotrophic flagellates...
occurred in the red and brownalgae). Diplobiontic green algae include isomorphic and heteromorphic forms. In isomorphic algae, the morphology is identical...
Kelps are large brownalgae or seaweeds that make up the order Laminariales. There are about 30 different genera. Despite its appearance, kelp is not...
Fucus is a genus of brownalgae found in the intertidal zones of rocky seashores almost throughout the world. The thallus is perennial with an irregular...
Macrocystis is a monospecific genus of kelp (large brownalgae) with all species now synonymous with Macrocystis pyrifera. It is commonly known as giant...
It is a herbivore that feeds on brownalgae, but its close relative A. californica feeds almost exclusively on red algae. This difference in food sources...
In archaeplastidans: some green algae (e.g., Cladophora glomerata, Acetabularia) In stramenopiles: some brownalgae (the Fucales, however, their life...
non-photosynthesizing plants are heterotrophic. In contrast, green plants, red algae, brownalgae, and cyanobacteria are all autotrophs, which use photosynthesis to...
normal population regulation and result in the overgrazing of kelp and other algae. This can rapidly result in transitions to barren landscapes where relatively...
filamentous or genuinely multicellular Phaeophyta (2,000 species), known as brownalgae; and the Chrysomonadea (>1,200 species). The heterotrophic stramenopiles...
brownalgae Giffordia mitchelliae. When their food algae (red and green algae) disappears during El Niños, the areas may be taken over by this brown algae...
events transferred it (with the arabinogalactan proteins) further into brownalgae and oomycetes. Plants later evolved various genes from CesA, including...
contributors to primary production in the ocean, including green algae, brownalgae and red algae, and a diverse group of unicellular groups. Vascular plants...
of macroscopic, multicellular, marine algae. The term includes some types of Rhodophyta (red), Phaeophyta (brown) and Chlorophyta (green) macroalgae. Seaweed...
an accessory pigment in the chloroplasts of brownalgae and most other heterokonts, giving them a brown or olive-green color. Fucoxanthin absorbs light...
biological processes by which photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into...
species are known to eat red slime algae, green film algae, hair algae, diatoms, cyanobacteria, brown film algae, detritus, and microalgae. There are...
strong preference for brownalgae in Benthic ecosystems, but due to removal of mesograzers by predators such as fish, brownalgae is able to dominate these...
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