Fragilariopsis cylindrus (Grunow ex Cleve) Helmcke et Krieger

Al-Handal, Adil Y., Torstensson, Anders & Wulff, Angela, 2022, Revisiting Potter Cove, King George Island, Antarctica, 12 years later: new observations of marine benthic diatoms, Botanica Marina (Warsaw, Poland) 65 (2), pp. 81-103 : 95

Fragilariopsis cylindrus (Grunow ex Cleve) Helmcke et Krieger ( Figures 91, 92 , 115, 116 )

Literature: ( Hasle 1965, p. 34, fig. 12:6–12; Snoeijs and Vilbaste 1994, p. 50, fig. 138; Witkowski et al. 2000, p. 360, pl. 213, figs. 8–14).

Description: Length 5–11 µm, width 2–3 µm, striae 15–20 in 10 µm, fibulae 15–20 in 10 µm.

Ecology and distribution: A common bipolar sea-ice diatom, particularly in summer and autumn ( Kang and Fryxell 1992) but also found in brackish-water of the Baltic Sea, forming ribbon-like colonies (Snoeijs and Vilbaste 1994). Fragilariopsis cylindrus has been used as an indicator species for sea-ice movement in both polar regions (von Quillfeldt 2004). It was not observed in Potter Cove during the previous collection. Rare in the material examined.

Figures

Figures 79–92: Marine benthic diatoms in Potter Cove, King George Island, Antarctica, summer 2015. (79) Gyrosigma arcuatum. (80) Gyrosigma fasciola. (81) Gyrosigma cf. obscurum. (82) Pleurosigma eudon var. kerguelensis. (83) Pleurosigm diversestriatum. (84) Pleurosigma strigosum. (85) Amphora gourdonii. (86) Amphora marina. (87, 88) Amphora sp. 1. (89) Amphora sp. 2. (90) Cylindrotheca closterium. (91, 92) Fragilariopsis cylindrus.

Figures 113–118: SEM images of the marine benthic diatoms in Potter Cove, King George Island, Antarctica, summer 2015. (113, 114) Cocconeis orbicularis, external and internal faces of sternum valve. (115, 116) Fragilariopsis cylindrus, internal valve sides. (117) Entomoneis paludosa. (118) Nitzschia australis.