Thorea

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Thorea
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Thorea

Thorea is a genus of freshwater algae in the Phylum Rhodophyta (red algae). [1] Thorea is a small alga with filaments up to 200 cm long, dark green in colour and not red as are marine Rhodophyta. The filaments have only as few secondary branches.

Fresh water Naturally occurring water with low amounts of dissolved salts

Fresh water is any naturally occurring water except seawater and brackish water. Fresh water includes water in ice sheets, ice caps, glaciers, icebergs, bogs, ponds, lakes, rivers, streams, and even underground water called groundwater. Fresh water is generally characterized by having low concentrations of dissolved salts and other total dissolved solids. Though the term specifically excludes seawater and brackish water, it does include mineral-rich waters such as chalybeate springs.

Red algae division of algae, red algae

Red algae, or Rhodophyta, are one of the oldest groups of eukaryotic algae. The Rhodophyta also comprises one of the largest phyla of algae, containing over 7,000 currently recognized species with taxonomic revisions ongoing. The majority of species (6,793) are found in the Florideophyceae (class), and mostly consist of multicellular, marine algae, including many notable seaweeds. Approximately 5% of the red algae occur in freshwater environments with greater concentrations found in warmer areas. Except for two coastal cave dwelling species in the asexual class Cyanidiophyceae, that diverged from other red algae about 1.3 billion years ago, there are no terrestrial species, which may be due to an evolutionary bottleneck where the last common ancestor lost about 25% of its core genes and much of its evolutionary plasticity.

Thorea is distributed throughout temperate and tropical regions. [2]

There is only one species of Thorea in the British Isles: Thorea hispida (Thore) Desvaux (Synonyms: Thorea anadina Lagerheim et K.Mobius, T. lehmannii Horneman and T. ramosissima Bory). [1]

British Isles Group of islands in northwest Europe

The British Isles are a group of islands in the North Atlantic off the north-western coast of continental Europe that consist of the islands of Great Britain, Ireland, the Isle of Man, the Hebrides and over six thousand smaller isles. They have a total area of about 315,159 km2 and a combined population of almost 72 million, and include two sovereign states, the Republic of Ireland, and the United Kingdom of Great Britain and Northern Ireland. The islands of Alderney, Jersey, Guernsey, and Sark, and their neighbouring smaller islands, are sometimes also taken to be part of the British Isles, even though, as islands off the coast of France, they do not form part of the archipelago.

The first record of Thorea ramosissima in the British Isles is in Harvey's Manual (1841): [3] Found in a pool in a bog in the Co Donegal Mountains, going from Letterkenny to Dunfanaghy; July. These specimens are in the Ulster Museum (BEL: F42–F47), but proved to have been incorrectly identified and were specimens of Batrachospermum . [4]

Ulster Museum part of the National Museum of Northern Ireland

The Ulster Museum, located in the Botanic Gardens in Belfast, has around 8,000 square metres of public display space, featuring material from the collections of fine art and applied art, archaeology, ethnography, treasures from the Spanish Armada, local history, numismatics, industrial archaeology, botany, zoology and geology. It is the largest museum in Northern Ireland, and one of the components of National Museums Northern Ireland.

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References

  1. 1 2 R. G. Sheath & A. R. Sherwood (2002). "Phylum Rhodophyta". In D. M. John, B. A. Whitton & A. J. Brook (ed.). The Freshwater Algal Flora of the British Isles. Cambridge University Press. Cambridge. ISBN   0-521-77051-3.
  2. D. M. John, L. R. Leslie & J. A. Moore (1989). "Observations on Thorea ramosissima Bory (Batrachospermales, Thoraceae), a freshwater red alga rarely recorded in the British Isles". Br. Phycol. J. 24: 99–102. doi:10.1080/00071618900650091.
  3. W. H. Harvey (1841). A Manual of the British Algae:... John van Voorst, London.
  4. D. M. John, J. A. Moore & L. R. Johnson (1990). "The red alga Thorea in the British Isles". Br. Phycol. Newsletter. 28: 11–12.