Photos / Sounds

Observer

lamawebber

Date

March 28, 2022 09:35 PM PDT

Description

Asterionella bleakeleyi W.Smith 1856

LM images of the marine diatom Asterionella bleakeleyi W. Smith 1856. Phylum: Bacillariophycophyta, Subphylum: Bacillariophytina, Class: Bacillariophceae, Order: Rhabdonematales, Family: Tabellariaceae.

Girdle view of the typical radiate colony of four cells. Asterionella bleakeleyi cells in girdle view have unequally inflated ends and are slightly inflated in the middle of the frustule. The proximal end of the valve (foot pole), attached to other cells in the colony, is slightly larger and distinctively capitate than the distal valve end. Pseudoraphe is narrow and the striae are very fine (Guiry and Guiry 2022, Patrick and Reimer, 1966).

The circular organism with a white halo on the proximal end of a cell (lower right side) appears to be fungal, likely a chytrid.

Cell length is reported between 45-65 µm (Patrick and Reimer, 1966). The length of cells in this specimen are 48 µm long.

Live, non-fixed. Rare. This is the first and so far, only record of A. bleakeleyi in the Trincomali Channel. Shim (1976) reported it as occasional in the Strait of Georgia. Collected by Arjan van Asselt with a 20 µm plankton net March 29, 2022 from the Spanish Hills Wharf (N48˚ 59.688’, W123˚ 35.064’), Trincomali Channel, Galiano Island, Southern Gulf Islands, British Columbia, Canada.

Imaging with a Nikon E800, 60x Apo NA 1.40 oil, and a MU2003 BI 20 MP camera, images stacked with HeliconSoft and adjusted in PhotoShop.

References:

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.

F.E. 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.

Patrick, R.M. and Reimer, C.W. (1966) The Diatoms of the United States exclusive of Alaska and Hawaii, V. 1 Monographs of the Academy of Natural Sciences of Philadelphia 13. p. 180 Plate 9, Fig. 6.

Shim, J. H. (1976). Distribution and Taxonomy of Planktonic Marine Diatoms in the Strait of Georgia, B.C. Phd. Thesis, UBC. P. 165, Plate 21, fig. 1.

Sims, P.A. (ed.) (1996). An atlas of British diatoms arranged by B. Hartley based on illustrations by H.G. Barber and J.R. Carter. pp. 72-73, Fig. 1. Bristol: Biopress Ltd.

Smith, W. (1856). A synopsis of the British Diatomaceae; with remarks on their structure, functions and distribution; and instructions for collecting and preserving specimens. The plates by Tuffen West. In two volumes. Vol. II. A-E. London: John van Voorst, Paternoster Row.

Photos / Sounds

Observer

lamawebber

Date

July 14, 2005 09:00 PM PDT

Description

Asterionellopsis glacialis (F. Castracane) Round 1990

Light microscope (LM) and Scanning Electron Microscope (SEM) images of the diatom Asterionellopsis glacialis (Castracane) Round 1990.

Phylum: Bacillariophycophyta, Class: Bacillariophyceae, Subclass: Urneidophycidae, Order: Rhaphoneidales, Family: Fragilariaceae. Girdle view. A cosmopolitan, sometimes highly abundant marine diatom in coastal cold to temperate waters. Heteropolar cells. Cells are attached by mucilage secreted from oval ocelli, with elongate openings, at the valve faces of the basal poles (see SEM images), forming stellate and spiral colonies. Basal end is triangular in girdle view and rounded in valve view with spines along the margin. A. glacialis has a labiate process at the valve end of the thin, slightly expanded extension (apex) (visible by SEM), it can be found near to the ocellus of the apex. Two chloroplasts found in the basal pole. Specimen from Spanish Hills Wharf, Trincomali Channel, North Galiano Island, Southern Gulf Islands, British Columbia, Canada, November 23, 2008, January 24, 2006, SEM images from December 17, 2009 and July 14, 2005.

Hitachi s4700 SEM at the BioImaging Facility at UBC, Vancouver. Many thanks to Elaine Humphrey for SEM assistance.

References:

M.D. Guiry in Guiry, M.D. & Guiry, G.M. 2021. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 20 October 2021. http://www.algaebase.org/search/species/detail/?species_id=37056

Hoppenrath, M., Elbrachter, M., Drebes, G. (2009) Marine Phytoplankton, Selected microphytoplankton species from the North Sea around Helgoland and Sylt. pp. 103-104, figs 44 m-n. E. Schweizerbart’sche Verlagsbunchhandlung, Stuttgart, Germany.

Horner, R. A. (2002), A Taxonomic Guide to Some Common Marine Phytoplankton. p. 93. Biopress Ltd., Bristol.

Hasle, G.R. & Syvertsen, E.E. (1997). Marine Diatoms. In: Identifying Marine Phytoplankton. (Tomas, C.R. Eds.), pp. 241-243. San Diego: Academic Press.

F.E. Round, R.M. Crawford, D.G. Mann, 1990, The Diatoms, Biology & Morphology of the Genera, pp. 392-393. Cambridge University Press, Cambridge, UK.