Home / Chlorophyceae / Filamentous / Unbranched / Planctonema
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Name derivation:
Classification:
Planctonema Schmidle 1903; 1 of 2 species descriptions is currently accepted taxonomically (Guiry and Guiry 2014). Microscopical studies revealed the facultative mucilaginous envelope and, interestingly, the layered character of apical cell wall thickenings bringing the cells within the filaments in a distant position (Skuja 1956; Bourrelly 1962; Heynig 1988). The position in the phylogenetic tree makes Planktonema a candidate to be included into Oocystaceae. The ultrastructural proof showing the fibrillar pattern of cell wall of Planctonema is unaccounted until now (Krienitz and Bock, 2011).
Morphology:
Unbranched, unattached filaments with cylindrical cells in a loose row, united in pairs that are surrounded by a homogenous mucilaginous sheath. Reproduction is done through fragmentation.
Similar genera:
Habitat:
Freshwater ponds and lakes The filamentous alga Planktonema lauterbornii dominated the entire warm period of the year (May–October) of lake Skadar, Albania and Montenegro. This species usually dominates the phytoplankton assemblage in highly eutrophic lakes (Rakočević, 2012). Planctonema lauterbornii is abundant in Lake Tahoe USA that receives atmospheric aerosols with a high ratio of ammonia to phosphate-P (Mackey et al. 2013).
References:
Guiry, M.D. and G.M. Guiry 2014. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 30 May 2014. Jelena Rakočević, J. 2012. Spatial and temporal distribution of phytoplankton in Lake Skadar. Archiv Biologische Science, Belgrade 64(2):585-592. Lothar Krienitz and Christina Bock. Elongatocystis ecballocystiformis gen. et comb. nov., and some reflections on systematics of Oocystaceae (Trebouxiophyceae, Chlorophyta). Fottea 11(2): 271–278, 2011. http://www.fottea.czechphycology.cz/pdfs/fot/2011/02/02.pdf. Mackey, K. R. M., Hunter, D., Fischer, E. V., Jiang, Y., Allen, B., Chen, Y., Liston, A., Reuter, J., Schladow and G., Paytan, A. 2013. Aerosol-nutrient-induced picoplankton growth in Lake Tahoe. Journal of Geophysical Research: Biogeosciences 118(3):1054-1067. http://dx.doi.org/10.1002/jgrg.20084 Schmidle, W. 1903. Bemerkungen zu einigen Süsswasseraigen. Berichte der Deutschen Botanischen Gessellschaft 21: 346-355, pl. XVIII (separately). Wehr, J.D., and R.G. Sheath (Eds.) 2002. The Freshwater Algal Flora of the British Isles. Cambridge University Press.