Red algae
Scientific classification
Domain: Eukaryota (unranked) Archaeplastida Phylum: Rhodophyta Wettstein, 1922
Possible classes
Florideophyceae Bangiophyceae Cyanidiophyceae

The red algae (Rhodophyta, IPA: /ˌroʊdəˈfaɪtə, roʊˈdɒfɨtə/, from Greek: ῥόδον (rhodon) = rose + φυτόν (phyton) = plant, thus red plant) is a large group, about 5,000–6,000 species ^[1] of mostly multicellular, marine algae, including many notable seaweeds. Animals Plants fungi, and Protists are eukaryotes (juːˈkærɪɒt or -oʊt Organisms whose cells are organized into complex The Archaeplastida or Primoplantae are a major line of Eukaryotes comprising the land plants green and Red algae and a small Richard Wettstein ( June 30, 1863 - August 10, 1931) was an Austrian Botanist. Florideophyceae is a class of Red algae They were once thought to be the only algae to bear Pit connections but these have since been found in the filamentous Bangiophyceae is a class of Red algae The Bangiophyceae as defined traditionally are Paraphyletic. Greek (el ελληνική γλώσσα or simply el ελληνικά — "Hellenic" is an Indo-European language, spoken today by 15-22 million people mainly Multicellular organisms are Organisms consisting of more than one cell, and having Differentiated cells that perform specialized functions An ocean (from Greek, ''Okeanos'' (Oceanus) is a major body of saline water, and a principal component of the Hydrosphere. Algae ( sing. alga are a large and diverse group of simple typically Autotrophic organisms ranging from Unicellular to Multicellular forms Seaweed is a loose colloquial term encompassing macroscopic Multicellular, benthic marine Algae. Other references indicate 10,000 species.  ^[2] Most of the coralline algae, which secrete calcium carbonate and play a major role in building coral reefs, belong here. Coralline algae are Red algae in the Family Corallinaceae of the order Corallinales. Calcium carbonate is a Chemical compound with the Chemical formula Ca[[Carbon C]] O 3 Coral reefs are Aragonite structures produced by living organisms found in marine waters with little to no nutrients in the water Red algae such as dulse (Palmaria palmata) and laver (nori/gim) are a traditional part of European and Asian cuisine and are used to make other products like agar, carrageenans and other food additives. Palmaria palmata (L Kuntze also called dulse, dillisk, dilsk or creathnach, is a Red alga ( Rhodophyta) previously Laver is an edible Seaweed that has a high Mineral salt content particularly Iodine and Iron. Nori (海苔 ( 김 kim or gim) is the Japanese name for various edible Seaweed species of the Red alga Porphyra Gim ( 김) sometimes spelled kim, is a Korean -style edible Seaweed in the genus Porphyra, similar Agar or agar agar is a Gelatinous substance derived from Seaweed. Carrageenans or carrageenins (ˌkærəˈgiːnənz are a family of linear sulphated Polysaccharides extracted from red Seaweeds The name is derived from Food additives are substances added to food to preserve flavour or improve its taste and appearance  ^[3]

A red alga in a California tide pool displaying some iridescence when not covered with water

Fossil record

The oldest fossil identified as a red alga is also the oldest fossil eukaryote that belongs to a specific modern taxon. California ( is a US state on the West Coast of the United States, along the Pacific Ocean. Tide pools (also tidal pools, rock pools or rock and roll pools) are rocky pools by Oceans that are filled with Seawater. Iridescence is an Optical phenomenon in which Hue changes with the angle from which a surface is viewed Animals Plants fungi, and Protists are eukaryotes (juːˈkærɪɒt or -oʊt Organisms whose cells are organized into complex A taxon (plural taxa) or taxonomic unit, is a name designating an organism or a group of Organisms In Biological nomenclature according to Bangiomorpha pubescens, a multicellular fossil from arctic Canada, strongly resembles the modern red alga Bangia despite occurring in rocks dating to 1200 million years ago. Country to "Dominion of Canada" or "Canadian Federation" or anything else please read the Talk Page  ^[4]

Red algae are important builders of limestone reefs. The earliest such coralline algae, the solenopores, are known from the Cambrian Period. Coralline algae are Red algae in the Family Corallinaceae of the order Corallinales. The Cambrian is a geologic period and system that began about Ma (million years ago at the end of the Proterozoic eon and ended about Ma with Other algae of different origins filled a similar role in the late Paleozoic, and in more recent reefs. The Paleozoic or Palaeozoic Era (from the Greek palaio (παλαιο "old" and zoe (ζωη "life" meaning "ancient life"

Taxonomy

The red algae are classified in the Archaeplastida, along with the glaucophytes and Viridiplantae (green algae and land plants). The Archaeplastida or Primoplantae are a major line of Eukaryotes comprising the land plants green and Red algae and a small The glaucophytes, also known as glaucocystophytes or glaucocystids, are a small group of freshwater microscopic Algae. Plants are living Organisms belonging to the kingdom Plantae.

Below are two valid published taxonomies of the red algae, although neither necessarily has to be used, as the taxonomy of the algae is still in a state of flux (with classification above the level of order having received little scientific attention for most of the 20th century). This article is about the taxonomic rank for the sequence of species in a taxonomic list see Taxonomic order In scientific classification used ^[5] If one defines the kingdom Plantae to mean the Archaeplastida, the red algae will be part of that kingdom; but if Plantae are defined more narrowly, to be the Viridiplantae, then the red algae might be considered their own kingdom^[5] or part of the kingdom Protista. Protists (ˈproʊtɨst are a diverse group of eukaryotic Microorganisms Historically protists were treated as the kingdom Protista but this The two classification systems below place the red algae in the plant kingdom.

Species of red algae

There are around 6,500 to 10,000 known species, ^[2][3] nearly all of which are marine, with about 200 that only live in fresh water. Plants are living Organisms belonging to the kingdom Plantae. The red algae (Rhodophyta ˌroʊdəˈfaɪtə roʊˈdɒfɨtə from Greek: ῥόδον (rhodon = rose + φυτόν (phyton = plant thus red plant are Bangiophyceae is a class of Red algae The Bangiophyceae as defined traditionally are Paraphyletic. Florideophyceae is a class of Red algae They were once thought to be the only algae to bear Pit connections but these have since been found in the filamentous Plants are living Organisms belonging to the kingdom Plantae. The red algae (Rhodophyta ˌroʊdəˈfaɪtə roʊˈdɒfɨtə from Greek: ῥόδον (rhodon = rose + φυτόν (phyton = plant thus red plant are Bangiophyceae is a class of Red algae The Bangiophyceae as defined traditionally are Paraphyletic. Florideophyceae is a class of Red algae They were once thought to be the only algae to bear Pit connections but these have since been found in the filamentous Freshwater is a word that refers to bodies of water such as Ponds lakes rivers and streams containing low concentrations of dissolved Salts and other Total dissolved However estimates of the number of real species vary by 100%.  ^[2]

Some examples of species and genera of red algae are:

• Atractophora hypnoides
• Gelidiella calcicola
• Lemanea, a freshwater genus
• Palmaria palmata, dulse
• Schmitzia hiscockiana
• Chondrus crispus, Irish moss
• Mastocarpus stellatus

Pit connections and pit plugs

Pit connections

Pit connections and pit plugs are unique and distinctive features of red algae that form during the process of cytokinesis following mitosis. Atractophora hypnoides PL Crouan & HMCrouan is a rare red alga ( Rhodophyta) found in the British Isles, France Gelidiella calcicola Maggs and Guiry is a rare seaweed species in the Rhodophyta, described for the first time in 1987 Lemanea is the generic name for an Alga of which occurs in the British Isles Palmaria palmata (L Kuntze also called dulse, dillisk, dilsk or creathnach, is a Red alga ( Rhodophyta) previously Schmitzia hiscockiana Maggs & Guiry is a small rare red Seaweed or marine Alga of the Rhodophyta or red algae Chondrus crispus, known under the common name Irish moss, or carrageen moss ( Irish carraigín, "little rock" is a species Mastocarpus stellatus, also called Clúimhín Cait Puff Carragheen or Carrageen Moss is closely related to Irish Moss, or Chondrus crispus Cytokinesis is the process whereby the Cytoplasm of a single Eukaryotic cell is divided to form two daughter cells In red algae, cytokinesis is incomplete. Typically, a small pore is left in the middle of the newly formed partition. The pit connection is formed where the daughter cells remain in contact.

Shortly after the pit connection is formed cytoplasmic continuity is blocked by the generation of a pit plug, which is deposited in the wall gap that connects the cells.

Connections between cells having a common parent cell are called a primary pit connections. Because apical growth is the norm in red algae, most cells have two primary pit connections, one to each adjacent cell.

Connections that exist between cells not sharing a common parent cells are labeled secondary pit connections. These connections are formed when an unequal cell division produced a nucleated daughter cell that then fuses to an adjacent cell. Patterns of secondary pit connections can be seen in the order Ceramiales.

Pit plugs

After a pit connection is formed, tubular membranes appear. A granular protein, called the plug core, then forms around the membranes. The tubular membranes eventually disappear. While some orders of red algae simply have a plug core, others have an associated membrane at each side of the protein mass, called cap membranes. The pit plug continues to exist between the cells until one of the cells dies. When this happens, the living cell produce a layer of wall material that seals off the plug.

Function

It is thought that the pit connections function as structural reinforcement, and as an avenue for cell to cell communication and/or symplastic transport in red algae. While the presence of the cap membrane could inhibit this transport between cells, it has been hypothesized that the tubular plug cores serve as a means of transport.

Human Consumption

Several species are used as food. Dulse (Palmaria palmata)^[7] and Porphyra are the best known in the British Isles. Palmaria palmata (L Kuntze also called dulse, dillisk, dilsk or creathnach, is a Red alga ( Rhodophyta) previously Palmaria palmata (L Kuntze also called dulse, dillisk, dilsk or creathnach, is a Red alga ( Rhodophyta) previously Porphyra is a foliose Red algal genus of laver, comprising approximately 70 species  ^[8]

In East and Southeast Asia, agar is most commonly produced from Gelidium amansii. Gelidium amansii is an economically important species of Red algae commonly found in the shallow coast of many East and Southeast Asian countries

See also

• Brown algae
• Green algae
• Red tide (red tides are caused by algae from the phylum Dinoflagellata, and not red algae [Rhodophyta])
• Françoise Ardré (namesake of the red alga known as Pterosiphonia ardreana)

References

External links

• Monterey Bay Flora
• Life cycle of red algae