Home / Cyanobacteria / Filaments / Unbranched / Untapered / No_heterocysts / No_visible_sheath / Romeria |
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Name derivation: |
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Classification: |
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Romeria Koczwara ex Geitler 1932; 15 of 20 species descriptions are currently accepted taxonomically (Guiry and Guiry 2013).Order Pseudanabaenales; Family PseudanabaenaceaeSynonyms according to Komárek (2001):Synonym: Raciborskia Koczwara 1929Synonym: Amalia De Toni 1934Synonym: Campylotropium Hortob. et Hilliard 1965
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Similar genera: |
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Coccoid genera Synechococcus and Rhabdoderma have ‘very similar’ cell morphology and cell division; Aphanothece strains have ’almost identical’ thylakoid arrangement (Komárek 2001).
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Morphology: |
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Filamentous and pseudofilamentous; trichomes solitary or rarely in microscopic colonies, free-floating, fine, few-celled, disintegrating to solitary cells, unbranched, irregularly to screw-like coiled, with sometimes freely connected cells by their ends, without sheaths (but enveloped usually by very fine, diffluent, colorless, slightly visible mucilaginous ‘envelopes’ when stained), always, isopolar, 0.6-3 μm wide, incut (constricted) at the cross walls, end cells not attenuated, immotile. Cells elongated, cylindrical, always longer than wide (usually several times), cut or rounded at the ends, without aerotopes; end cells cut or rounded. Cell content pale blue-green, greyish or yellowish, usually homogeneous. No heterocysts, akinetes, or gas vesicles (Guiry and Guiry 2013). No sheath (Komárek 2001)
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Nitrogen preference: |
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In mesocosms mimicking commercial shrimp ponds, Romeria preferred ammonium but utilized urea (dissolved organic nitrogen) as well as dinoflagellates. Nitrate and bio-available phosphate levels remained low during experiments where either N15-ammonium chloride or N15-urea were added to 1 L incubation bottles (Burford 2005).
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Habitat: |
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Freshwater plankton in meso- to eutrophic lakes, reported only from northern hemisphere to date. One marine species (R. Mexicana) reported from Gulf of Mexico. Also marine plankton.
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References: |
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Burford, M.A. 2005. Relative uptake of urea and ammonium by dinoflagellates or cyanobacteria in shrimp mesocosms. Hydrobiologia 549:297-303. Geitler, L. 1932. Cyanophyceae. In: Kryptogamen-Flora von Deutschland, Österreich und der Schweiz. (Rabenhorst, L. Eds) Vol. 14, pp. 673-1056. Leipzig: Akademische Verlagsgesellschaft. Guiry, M.D. and G.M. Guiry 2013. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 22 May 2013. Komárek, J. 2001. Review of the cyanoprokaryotic genus Romeria. Czech Phycology, Olomouc 1:5-19. |
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Home / Cyanobacteria / Filaments / Unbranched / Untapered / No_heterocysts / No_visible_sheath / Romeria |