algal bloom

Snowella

Taxonomy

Order
Synechococcales
Family
Coelosphaeriaceae
Genus
Snowella

Examples of Snowella


snowella

400X total magnification; 10 μm scale bar.

snowella

400X total magnification; 10 μm scale bar.

snowella

400X total magnification.

Morphology

Microscopic colonies, spherical to oval in shape; sometimes composed of subcolonies; surrounded by a fine, diffuse mucilage. Cells are held at the ends of thin gelatinous stalks, which radiate from the colony center; stalks are nearly pseudodichotomously branched (each stalk branches into two more stalks, each roughly equal in length and thicknes); stalks usually widened towards the colony center, and may be confluent. Cells are held by the stalks at the periphery of the colony; are often somewhat radially displaced from one another, rather than forming one uniform peripheral layer; usually distant from one another, but if densely arranged on the colony periphery, then at least with small spaces between cells (compare to Gomphosphaeria, whose cells remain joined together for a long period following division). Cells spherical to slightly radially elongated; 0.6-4.2 μm in length or diameter; pale blue-green, olive-green, or yellowish; two species have one to several central aerotopes.

Ecology

Free-floating colonies, planktic in temperate fresh and brackish waters, especially in cold mesotrophic lakes.

References

  • Johansen, J. R., & Komárek, J. (2015). Coccoid Cyanobacteria. In J. D. Wehr, R. G. Sheath, & J. P. Kociolek (Eds.), Freshwater Algae of North America: Ecology and Classification (2nd ed., pp. 91-101). Waltham, MA: Elsevier.
  • Komárek, J. & Anagnostidis, K. (2008). Cyanoprokaryota-1. Teil/Part 1: Chroococcales. In H. Ettl, G. Gärtner, H. Heynig, & D. Mollenhauer (Eds.), Süßwasserflora von Mitteleuropa (Vol. 19/1, p. 204). Heidelberg, Germany: Spektrum.