UC San Diego UC San Diego Previously Published Works Title Diversity of the diatom genus Fragilariopsis in the Argentine Sea and Antarctic waters: morphology, distribution and abundance Permalink https://escholarship.org/uc/item/5p2517zr Journal Polar Biology, 33(11) ISSN 1432-2056 Authors Cefarelli, Adrián O. Ferrario, Martha E. Almandoz, Gastón O. et al. Publication Date 2010-11-01 DOI 10.1007/s00300-010-0794-z Peer reviewed eScholarship.org Powered by the California Digital Library University of California Polar Biol (2010) 33:1463–1484 DOI 10.1007/s00300-010-0794-z ORIGINAL PAPER Diversity of the diatom genus Fragilariopsis in the Argentine Sea and Antarctic waters: morphology, distribution and abundance Adria´n O. Cefarelli • Martha E. Ferrario • Gasto´n O. Almandoz • Adria´n G. Atencio • Rut Akselman • Marı´a Vernet Received: 9 October 2009 / Revised: 2 March 2010 / Accepted: 12 March 2010 / Published online: 16 October 2010 Ó The Author(s) 2010. This article is published with open access at Springerlink.com Abstract Fragilariopsis species composition and abun- Drake Passage and twelve in the Weddell Sea. F. curta, dance from the Argentine Sea and Antarctic waters were F. kerguelensis, F. pseudonana and F. rhombica were analyzed using light and electron microscopy. Twelve present everywhere. species (F. curta, F. cylindrus, F. kerguelensis, F. nana, F. obliquecostata, F. peragallii, F. pseudonana, F. rhombica, Keywords Phytoplankton Á Diatom Á Fragilariopsis Á F. ritscheri, F. separanda, F. sublinearis and F. vanheurckii) Antarctica Á Argentine Sea are described and compared with samples from the Frengu- elli Collection, Museo de La Plata, Argentina. F. peragallii was examined for the first time using electron microscopy, Introduction and F. pseudonana was recorded for the first time in Argentinean shelf waters. New information on the girdle The Argentine Sea, the Polar Front and the Weddell Sea are view is included, except for the species F. curta, F. cylindrus characterized by high primary productivity and rich phy- and F. nana, for which information already existed. In the toplankton communities (Longhurst 1998; Romero et al. Argentine Sea, F. pseudonana was the most abundant 2006; Schloss et al. 2007). Phytoplankton are the main Fragilariopsis species, and in Antarctic waters, F. curta was source of organic carbon in the ocean and are subject to high most abundant. Of the twelve species of Fragilariopsis spatial variability and strong seasonality (Fischer et al. documented, four occurred in the Argentine Sea, nine in the 2002). The abundance, composition and cell size distribu- tion of phytoplankton communities influence the flow of organic carbon in pelagic waters (Schloss and Estrada A. O. Cefarelli (&) Á M. E. Ferrario Á G. O. Almandoz Á 1994). Large phytoplankton organisms (microplankton, A. G. Atencio [20 lm) are commonly associated with productive areas in Departamento Cientı´fico Ficologı´a, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Paseo del the Southern Ocean, while smaller flagellates (nanoplank- Bosque s/n, 1900 La Plata, Argentina ton, 2–20 lm) dominate areas of lower productivity (Fryxell e-mail: [email protected] 1989; Kang and Fryxell 1993). Diatoms in chains and Phaeocystis antarctica Karsten are found at the ice edge in M. E. Ferrario Á G. O. Almandoz Á A. G. Atencio CONICET, Consejo Nacional de Investigaciones Cientı´ficas y the spring as well as at oceanic fronts (Kang et al. 2001; Te´cnicas, Av. Rivadavia 1917 (1033), Buenos Aires, Argentina Krell et al. 2005). Diatoms such as Fragilariopsis curta (van Heurck) Hustedt and F. cylindrus (Grunow ex Cleve) R. Akselman Frenguelli can dominate the water column, sea ice and ice- Instituto Nacional de Investigacio´n y Desarrollo Pesquero, V. Ocampo 1, Escollera Norte, B7602HSA Mar del Plata, edge communities (Garrison et al. 1987; Garrison and Buck Argentina 1989; Kang and Fryxell 1993; Socal et al. 1997; Hegseth and von Quillfeldt 2002). Nanoplankton is usually charac- M. Vernet terized by cryptomonads, single cell Phaeocystis antarc- Integrative Oceanography Division, Scripps Institution of Oceanography, University of California San Diego, tica, Pyramimonas spp. and small diatom species (Garibotti La Jolla, CA 92093-0218, USA et al. 2003). 123 1464 Polar Biol (2010) 33:1463–1484 The predominance of diatoms in the Southern Ocean has elliptical-linear-lanceolate, and isopolar or heteropolar in been well documented and was first described in early valve view. The canal raphe is markedly eccentric, not research expeditions (Hooker 1844). Productive areas, such raised above the level of the valve and without poroids in as the Western Antarctic Peninsula (Walsh et al. 2001; the outer wall (Hasle 1965, 1993; Round et al. 1990). The Garibotti et al. 2003; Pre´zelin et al. 2004), the Weddell Sea valve striae are separated by robust interstriae and gener- (Fryxell and Kendrick 1988), Prydz Bay (Kopczyn´ska et al. ally have two rows of poroids (rarely more than two and 1995), the Bellingshausen Sea (Barlow et al. 1998; van sometimes only one). In general, the striae are parallel, Leeuwe et al. 1998) and the Ross Sea (Arrigo et al. 1999), except near the poles (Round et al. 1990; Hasle and tend to be rich in diatoms (Kopczyn´ska et al. 2007; Syvertsen 1997). The valve mantle can be unperforated or Kozlowski 2008). Productive waters of the Argentine Sea can have striae with one or more rows of poroids. Girdle (Southwestern South Atlantic) are also rich in diatoms bands are unperforated or show one or more rows of por- (e.g., Carreto et al. 1981; Akselman 1996; Almandoz et al. oids (Hasle 1965; Medlin and Sims 1993). In general, there 2007). Diatoms can be identified by microscopy, pigment is little information on the girdle view of the different content or genetic analyses. The need for improved meth- Fragilariopsis species. The cells have two chloroplasts, ods to identify diatoms as well as additional information to one at each side of the median transapical plain (Hasle and improve the use of existing techniques is an ongoing Syvertsen 1997). research effort. Diatom samples from Antarctica and Argentina, col- Fragilariopsis Hustedt is a marine diatom genus that lected by Dr. Joaquı´n Frenguelli (1883–1958) and others, includes planktonic, a few benthic and some ice-associated are catalogued and compiled as the ‘‘Coleccio´nde species (Hasle and Medlin 1990; Round et al. 1990). Many Diatomeas Argentinas Dr. J. Frenguelli’’. The collection is of them are well preserved in marine sediments and are located at the Museo de La Plata, La Plata, Argentina. used in paleoceanography for past productivity estimates Permanent slides (2,435) are catalogued and organized by (e.g., Zielinski and Gersonde 1997; Abelmann et al. 2006). sample (Ferrario et al. 1995). With 459 new taxa (genera, Fragilariopsis has a wide geographical distribution but is species, varieties and forms) and 38 type materials from mainly found in polar waters, especially Antarctica, where Antarctica, Frenguelli’s collection is frequently consulted many species can be found, usually in great abundance for taxonomic studies (e.g., Hasle 1964, 1965; Simonsen (Frenguelli 1943; Frenguelli and Orlando 1958, 1959; 1974; Ferrario et al. 2008; Fernandes and Sar 2009). As Hasle and Medlin 1990; Round et al. 1990). However, the collection includes multiple Fragilariopsis species, F. pseudonana (Hasle) Hasle is a cosmopolitan species, we consulted it for this study (Frenguelli 1943, 1960; and F. doliolus (Wallich) Medlin and Sims is restricted to Frenguelli and Orlando 1958, 1959). warm waters (Hasle 1976; Medlin and Sims 1993; Hasle The objective of this study was to identify and describe and Syvertsen 1997). Some Fragilariopsis species are the Fragilariopsis diatom species found in neritic and found in the Southwestern Atlantic Ocean (Brandini et al. oceanic surface waters of the Argentine Sea, Drake Passage 2000; Romero and Hensen 2002; Olguı´n et. al 2006), but and Weddell Sea by light and electron microscopy. Twelve their occurrence in Argentine shelf waters is poorly docu- species were documented. Previous descriptions on Frag- mented (Ferrario and Galva´n 1989; Vouilloud 2003). ilariopsis species were expanded, and important details on The genus Fragilariopsis was established by Hustedt in girdle view were provided for the first time. F. peragallii 1913 by separating Fragilariopsis from the genus Fragi- (Hasle) Cremer was examined for the first time using laria Lyngbye. In 1972, Hasle reduced Fragilariopsis to a electron microscopy. Species relative abundance and con- section of the genus Nitzschia Hassall, arguing that a real centration were given and compared with abundance of difference between these genera did not exist. In 1990, other diatom species and total phytoplankton. Round et al. preferred to give Fragilariopsis generic status in view of the enormous diversity already present in Nitzschia and considering that Fragilariopsis appeared to Materials and methods be a natural group. Later, in 1993, Hasle recognized Fragilariopsis to generic status, emending its diagnosis and The present work is based on the analysis of phytoplankton making new combinations. However, the molecular anal- samples collected in the South Atlantic and Antarctic yses indicated that Fragilariopsis and Pseudo-nitzschia are waters. During the expedition ARGAU I Project ‘‘Coop- very closely related genera and they might be congeneric eration Program between France and ARGentina for the (Lundholm et al. 2002). The cells in Fragilariopsis are study of the AUstral Atlantic Ocean’’ (19–26 February usually united by the whole or the majority of the valve 2001), 36 quantitative and qualitative samples were col- face into flat, ribbon-like colonies; single cells appear only lected onboard the icebreaker ARA Almirante Irizar along occasionally. The frustules are rectangular in girdle view, three north–south transects: (1) continental shelf of the 123 Polar Biol (2010) 33:1463–1484 1465 Argentine Sea (AS), (2) Drake Passage (DP) and (3) Quantitative samples from ARGAU I were collected Weddell Sea (WS) (Fig.