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Genus: Grammatophora Ehrenberg, C.G. (1840).
The type species (lectotype) of the genus Grammatophora is Grammatophora angulosa Ehrenberg (Guiry and Guiry 2023)

Taxonomic notes on the genera:

Phylum Bacillariophyta
Subphylum Bacillariophytina
Class Bacillariophyceae
Subclass Fragilariophycidae
Order Rhabdonematales
Family Grammatophoraceae

Found on Z. marina at Montague Harbour Marine Provincial park (MHMPP)

Taxonomic characteristics of the genus:

1. An araphid genus, they often form zig-zag colonies attached to marine substrates
2. In girdle view the cells appear rectangular to square
3. In valve view the cells are elongate with rounded apices and no distinct central area
4. The girdle bands, closet to the valves (valvocopula) display distinctive undulating septa
5. The septa, either highly undulate or straight run from the apex of the girdle band nearest the valve (valvocopula) and terminate close to the cell centre. Towards the centre, the septa sometimes hooks back towards the valve. As the cell decreases in size the septa change shape and become less undulate, except for the hooked end which is morphologically stable (Sato et al. 2010)
6. Apical pore fields, where there are generally small spines
7. Pseudosepta located at the apices
8. Areolae are fine, poroid, uniserate and transverse, linearally arranged or five poroids arranged in a cross (quincunx pattern)
9. Chloroplasts are four per cell, filling the space in the septa
10. Two rimoportulae located close to the apices (Round et al. 1990, Sato et al. 2010, Spaulding et al. 2021)

Methods:
Collected by brushing or scrapping leaf sections of Z. marina from MHMPP, August 3, 2020, October 16, 2020, March 7, 2021 and July 2021. Cells were cleaned with concentrated hydrogen peroxide or nitric acid at 100 C for 3-5 hours to remove organics, then rinsed multiple times in ddH20 to a neutral pH. Mounted on SEM stubs or in Naphrax on slides for light microscopy. Imaging with a Nikon TE300 and Tuscen DigiRetna16 MP camera or Nikon E800.
Live specimens were imaged with either a Nikon TE300 or Nikon E800 with either bright-field or DIC. In-situ, environmentally prepared samples were made using minimal contact of 8-10 mm leaf section, soaked in ddH2O to remove salts and dried through an EtOH series (50%-100%) and finished off with 100% Hexamethyldisilane HMDS (Hazrin-Chong and Manefield 2012). Mounted on carbon stickies onto aluminum SEM stubs and imaged with either the Hitachi s4800 or TM4000 at AMF, at University of Victoria, B.C. My thanks to Siobhan Schenk and Laura Parfrey in the Parfrey Lab at UBC for molecular data from the eelgrass and a collaboration with IMERSS. Also thanks go to Elaine Humphrey of the AMF, UVIC, imaging by Ron Read, Melanie Quenneville and Arjan van Asselt. Imaging, taxonomy and identifications by M. Webber.

References:

Al-Yamani, F., and M. A. Saburova, M. (2011). Illustrated Guide on the Benthic Diatoms of Kuwait’s Marine Environments,” Kuwait Institute for Scientific Research, Lucky Press. p. 148. Plate 156. a-b.

Siqueiros Beltrones D. A., U. Argumedo Hernández and C. Landa Cancigno. 2015. Uncommon species diversity values in epiphytic diatom assemblages of the kelp Eisenia arborea. Hidrobiológica 26 (1): 61-76.

Guiry, M.D. in Guiry, M.D. & Guiry, G.M. 2020. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 4 November 2023.

Hazrin-Chong NH, Manefield M. (2012 ). An alternative SEM drying method using hexamethyldisilazane (HMDS) for microbial cell attachment studies on sub-bituminous coal. J Microbiol Methods. 90(2):96-9. doi: 10.1016/j.mimet.2012.04.014.

Mather et al. (2010). A Checklist of Diatom Species Reported (and Presumed Native) from Canadian Coastal Waters. Fisheries and Oceans Canada (https://publications.gc.ca/collections/collection_2010/mpo-dfo/Fs97-6-2881-eng.pdf).

Plinski, M. & Witkowski, A. (2020). Diatoms from the Gulf of Gdansk and surrounding waters (the southern Baltic Sea). pp. [1]-442, incl. 31 SEM pls, 16 photo pls. Gdansk: Gdansk University Press.

Rao, V.N.R. and Levin, J. 1976. Benthic marine diatom flora of False Bay, San Juan Island, Washington. Syesis, 9:173–213.

Round, F.E.,Crawford, R.M. & Mann, D.G. (1990), The Diatoms, Biology & Morphology of the Genera, pp. 436-437. Cambridge University Press, Cambridge, UK.

Sato, S., Nagumo, T. & Tanaka, J. (2003). Morphology and Taxonomy of Five marine attached diatoms in the genus Grammatophora Ehrenberg (Bacillariophyceae) in Japan. Japanese J. of Phycology 51 (supplement): 183-187.

Sato, S., Nagumo, T. and Tanaka, J. (2010): Morphological Study of Three Marine Araphid Diatom Species of Grammatophora Ehrenberg, with special reference to the septum structure
, Diatom Research, 25:1, 147-162. http://dx.doi.org/10.1080/0269249X.2010.9705835

Saunders, K., Lane, C., Cook, S., McMinn, A., & Hallegraeff, G. Benthic Diatoms: in Jameson, I. & Hallegraeff, G.M. (2010). Planktonic diatoms. In: Algae of Australia. Phytoplankton of temperate waters. (Hallegraeff, G.M., Bolch, C.J.S., Hill, D.R.A., Jameson, I, LeRoi, J.-M., McMinn, A., Murray, S., de Salas, M.F. & Saunders, K. Eds), pp. 122-123. fig 3.3A. Canberra & Melbourne: ABRS; CSIRO Publishing.

Shim, J. H. (1976). Distribution and Taxonomy of Planktonic Marine Diatoms in the Strait of Georgia, B.C. Phd. Thesis, UBC. p. 186. p. 246 Plate XXIV. FIG. 11.

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. [2], 1-601, incl. 290 pls. Bristol: Biopress Ltd.

Tynni, R. (1986). Observations of diatoms on the coast of the state of Washington. Geological Survey of Finland, Report of Investigation 75.

Witkowski, A., Lange-Bertalot, H. & Metzeltin, D. (2000). Diatom flora of marine coasts I. Iconographia Diatomologica 7: 1-925, incl. 219 pls with 4504 figs.

Mag. 100x (1,3,5), 400x (2,4,6)
Very large pennate diatom (common in this water sample); 3 specimens were photographed with lengths 520µ, 540µ, and 575µ. Images 1 and 2 suggest a clash of Titans; the 230µ long Pinnularia (perhaps P. pulchella) is less than half the length of its rival. Images 3-6 record the 2nd & 3rd specimens (dead; frustules more exposed) of this huge pennate diatom. roman_romanov speculates these giants belong to the genus Nitzschia or Tribonella (https://www.inaturalist.org/observations/124342691).

• After gently pushing aside the cover of lily pads, a pond side water sample was taken on 07/16/2022 using a 10µ dip net to enrich for microbes. Air temp. 79°F.

Composite epiphytic and epilithic sample from the edge of the Trinity River.

Length: 116 um, Breadth: 35 um.

Characteristics: 3 inflations in larger specimens, a single rimoportula, and transapical bars that look like music notes in girdle view.

Mag. 400x
Freshwater, asymmetric diatom. The 3 photos in image 1 depict a small rotation around its longitudinal axis. Based on its uniquely large size (180µ L x 50µ W), apiculate and capitate apices, striae count per 10µ (7 at the valve center and 9 near the apices), this specimen (to my eyes) looks like Cymbopleura inequalis. For more information and reference photos see https://diatoms.org/species/cymbopleura_inaequalis and https://www.algaebase.org/search/species/detail/?species_id=q6409a9e46e8376c6.

• A water sample was taken on 11/08/2022, from the shore of Lantern Hill Pond, using a 10µ dip net to enrich for microbes. Air temp. 55°F.

Images 1-7

1. Algae sampled just below pontoon water line.
2. Filament structure.
3. Filament structure.
4. Cell structure.
5. Filaments structure.
6. Cell structure.
7. Matted strands forming tufts.

NOT N. bisulcatum, except maybe the first 3. N. bisulcatum sensu strictu has a width range of 8-9 microns. The majority of the specimens here are a similar taxon that has been erroneously lumped into the species concept of N. bisulcatum by many authors over the course of the last century.

Scale bar = 10 µm.

Found alive and well in a culture in our incubator neglected since the onset of the pandemic. Interestingly enough, some cultures contained dead tardigrades and live rotifers. Source material was antarctic algal mats. Photo taken using darkfield.

Featureless transparent disks under PPL, but black interference crosses which maintain their orientation when the stage is spun appear under cross polarized light. The interference crosses may separate in some (typically larger) loricae forming patterns like the stitches on a baseball as the stage is rotated.