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Thalassiosira nordenskioeldii Cleve 1873

SEM images of the marine diatom Thalassiosira nordenskioeldii (Castracane) Hasle 1983.

Phylum: Bacillariophycophyta, Subphylum: Bacillariophytina,
Class: Mediophyceae,
Order: Thalassiosirales,
Family: Thalassiosiraceae,
Genus: Thalassiosira.

Girdle view. Thalassiosira nordenskioeldii cells are cylindrical to discoid and usually joined together in long chains. Cell diameter is recorded between 8.6-50 µm in diameter. In girdle view T. nordenskioeldii cells appear as octagonal discs. They have a pronounced concavity at the valve center from which a thick mucilage tube connects to the centre of a neighbouring cell. Areolation delicate, hexagonal areolae in sectors; 14 to 18 areolae in 10 µm. Central strutted process close to central areola (annulus). Marginal processes prominent with long external tubes, with a collar at the end;
three processes in 10 µm. Location of labiate process variable within the ring of strutted processes. Mantle edges are beveled. Long radiating mucilage threads exit from the prominent marginal strutted processes at the bend between the valve face and the mantle.

Methods:

Abundant, especially during the spring bloom in the Trincomali Channel. Collected by a 60 µm plankton net April 25, 2022 from Porlier Pass, Trincomali Channel, Galiano Island, Southern Gulf Islands, British Columbia, Canada. Thanks to Andrew Simon for collecting the sample.

Cleaning by nitric acid on a coverslip and rinses in lab grade water. Cover slip mounted on to SEM stubs. Imaging with a Hitachi TM4000 Plus SEM at the AMF at UVIC. Thank you Elaine Humphrey for SEM support. Adjusted in PhotoShop. Preparation, imaging and taxonomy by Mark Webber.

References:

Cupp, E. E. 1943. Marine Plankton Diatoms of the West Coast of North America. University of California Press. Berkeley, California.

Hoppenrath, M., Elbrachter, M., Drebes, G. (2009) Marine Phytoplankton, Selected microphytoplankton species from the North Sea around Helgoland and Sylt. pp. 59, figure 5. Plate 24, page 58:fig. f-k. E. Schweizerbart’sche Verlagsbunchhandlung, Stuttgart, Germany.

Horner, R. A. (2002), A Taxonomic Guide to Some Common Marine Phytoplankton. p. 31. Biopress Ltd., Bristol.

Hasle, G.R. & Syvertsen, E.E. (1996). Marine Diatoms. In: Identifying Marine Phytoplankton. (Tomas, C.R. Eds). San Diego: Academic Press.

Guiry, M.D. & Guiry, G.M. 2007, AlgaeBase version 4.2. World-wide electronic publication, National University of Ireland, http://algaebase.org, searched April 10, 2022.

Round, F.E., Crawford, R.M. and Mann, D.G. (1990). The Diatoms, Biology & Morphology of the Genera. Cambridge University Press, Cambridge, UK. pp. 132-133.

Fryxell, G.A. and Hasle, G.R. (1979). The genus Thalassiosira: species with internal extensions of the strutted processes. Phycologia. vol. 18 (4), 378-393.

Pienitz, R., Fedje, D. and Poulin, M. (2003) Marine and Non-Marine Diatoms from the Haida Gwaii Archipelago and Surrounding Coasts, Northeastern Pacific, Canada In Bibliotheca Diatomologica (H. Lange-Bertalot and P. Kociolek, eds.), Band 48, J. Cramer, Stuttgart, 146 pp.

Shim, J. H. (1976). Distribution and Taxonomy of Planktonic Marine Diatoms in the Strait of Georgia, B.C. Phd. Thesis, UBC. Plate VII, fig. 2a & b.

Waters, R. E., Brown, L.N., and MG Robinson, M.G. (1992). Phytoplankton of Esquimalt Lagoon, British Columbia: comparison with west Vancouver Island coastal and offshore waters. Canadian Technical Report of Hydrography Ocean Sciences 137.

@earely_bird I went back to find the gall but somehow could not track down the one I had this morning. Found this other one that I think is the same species as it can’t have been more than 15 feet from the original. I have it with me now, wanted to know if I should dissect or put it in a jar for you. If it’s that species you mentioned with no obs would rather rear it I figure. Let me know