Red algae

Red algae
Temporal range: Mesoproterozoic–present[1][2]
A-D : Chondrus crispus Stackhouse,
E-F : Mastocarpus stellatus J.Ag.
Scientific classification Edit this classification
Domain: Eukaryota
Clade: Diaphoretickes
Clade: CAM
Clade: Archaeplastida
Division: Rhodophyta
Wettstein, 1922
Clades

Red algae, or Rhodophyta (/roʊˈdɒfɪtə/, /ˌroʊdəˈfaɪtə/; from Ancient Greek ῥόδον (rhódon) 'rose' and φυτόν (phutón) 'plant'), make up one of the oldest groups of eukaryotic algae.[3] The Rhodophyta comprises one of the largest phyla of algae, containing over 7,000 recognized species within over 900 genera[4] amidst ongoing taxonomic revisions.[5] The majority of species (6,793) are Florideophyceae, and mostly consist of multicellular, marine algae, including many notable seaweeds.[5][6] Red algae are abundant in marine habitats.[7] Approximately 5% of red algae species occur in freshwater environments, with greater concentrations in warmer areas.[8] Except for two coastal cave dwelling species in the asexual class Cyanidiophyceae, no terrestrial species exist, which may be due to an evolutionary bottleneck in which the last common ancestor lost about 25% of its core genes and much of its evolutionary plasticity.[9][10]

Red algae form a distinct group characterized by eukaryotic cells without flagella and centrioles, chloroplasts without external endoplasmic reticulum or unstacked (stroma) thylakoids, and use phycobiliproteins as accessory pigments, which give them their red color.[11] Despite their name, red algae can vary in color from bright green, soft pink, resembling brown algae, to shades of red and purple, and may be almost black at greater depths.[12][13] Unlike green algae, red algae store sugars as food reserves outside the chloroplasts as floridean starch, a type of starch that consists of highly branched amylopectin without amylose.[14] Most red algae are multicellular, macroscopic, and reproduce sexually. The life history of red algae is typically an alternation of generations that may have three generations rather than two.[15] Coralline algae, which secrete calcium carbonate and play a major role in building coral reefs, belong there.

Red algae such as Palmaria palmata (dulse) and Porphyra species (laver/nori/gim) are a traditional part of European and Asian cuisines and are used to make products such as agar, carrageenans, and other food additives.[16]

  1. ^ N. J. Butterfield (2000). "Bangiomorpha pubescens n. gen., n. sp.: implications for the evolution of sex, multicellularity, and the Mesoproterozoic/Neoproterozoic radiation of eukaryotes". Paleobiology. 26 (3): 386–404. Bibcode:2000Pbio...26..386B. doi:10.1666/0094-8373(2000)026<0386:BPNGNS>2.0.CO;2. ISSN 0094-8373. S2CID 36648568.
  2. ^ T.M. Gibson (2018). "Precise age of Bangiomorpha pubescens dates the origin of eukaryotic photosynthesis". Geology. 46 (2): 135–138. Bibcode:2018Geo....46..135G. doi:10.1130/G39829.1.
  3. ^ Lee, R.E. (2008). Phycology (4th ed.). Cambridge University Press. ISBN 978-0-521-63883-8.
  4. ^ Frey, Wolfgang; Engler, Adolf; Jaklitsch, Walter M.; Kamiya, Mitsunobu; Begerow, Dominik; McTaggart, Alistair; Agerer, R.; Fischer, Eberhard; Müller, Kai, eds. (2017). Syllabus of plant families: Adolf Engler's Syllabus der Pflanzenfamilien. Part 2/2: Photoautotropic eukaryotic algae, Rhodophyta (13th ed.). Berlin: Gebr. Borntraeger Verlagsbuchhandlung. ISBN 978-3-443-01094-2. OCLC 911004269.
  5. ^ a b Guiry, M.D.; Guiry, G.M. (2016). "Algaebase". www.algaebase.org. Retrieved November 20, 2016.
  6. ^ D. Thomas (2002). Seaweeds. Life Series. Natural History Museum, London. ISBN 978-0-565-09175-0.
  7. ^ Dodds, Walter Kennedy; Whiles, Matt R. (7 May 2019). Freshwater ecology : concepts and environmental applications of limnology (Third ed.). London, United Kingdom: Academic Press. ISBN 9780128132555. OCLC 1096190142.
  8. ^ Sheath, Robert G. (1284). "The biology of freshwater red algae". Progress Phycological Research. 3: 89–157.
  9. ^ "Huan Qiu Red Algae DEENR at Rutgers SEBS". deenr.rutgers.edu.
  10. ^ Azua-Bustos, A; González-Silva, C; Arenas-Fajardo, C; Vicuña, R (2012). "Extreme environments as potential drivers of convergent evolution by exaptation: the Atacama Desert Coastal Range case". Front Microbiol. 3: 426. doi:10.3389/fmicb.2012.00426. PMC 3526103. PMID 23267354.
  11. ^ W. J. Woelkerling (1990). "An introduction". In K. M. Cole; R. G. Sheath (eds.). Biology of the Red Algae. Cambridge University Press, Cambridge. pp. 1–6. ISBN 978-0-521-34301-5.
  12. ^ Reece, Jane B.; Meyers, Noel; Urry, Lisa A.; Cain, Michael L.; Wasserman, Steven A.; Minorsky, Peter V. (May 20, 2015). Campbell Biology Australian and New Zealand Edition. Pearson Higher Education AU. ISBN 978-1-4860-1229-9 – via Google Books.
  13. ^ Morrissey, John; Sumich, James (June 11, 2012). Introduction to the Biology of Marine Life. Jones & Bartlett Publishers. ISBN 978-0-7637-8160-6 – via Google Books.
  14. ^ Viola, R.; Nyvall, P.; Pedersén, M. (2001). "The unique features of starch metabolism in red algae". Proceedings of the Royal Society of London B. 268 (1474): 1417–1422. doi:10.1098/rspb.2001.1644. PMC 1088757. PMID 11429143.
  15. ^ "Algae". autocww.colorado.edu. Archived from the original on 2012-03-15. Retrieved 2012-11-30.
  16. ^ M. D. Guiry. "Rhodophyta: red algae". National University of Ireland, Galway. Archived from the original on 2007-05-04. Retrieved 2007-06-28.