Revisiting Potter Cove, King George Island, Antarctica, 12 years later: new observations of marine benthic diatoms Author Al-Handal, Adil Y. Author Torstensson, Anders Author Wulff, Angela text Botanica Marina 2022 Warsaw, Poland 2022-02-23 65 2 81 103 http://dx.doi.org/10.1515/bot-2021-0066 journal article 10.1515/bot-2021-0066 1437-4323 11000147 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.