Distribution of spring phytoplankton (mainly diatoms) in the upper 50 m of the Southwestern Atlantic Ocean (30-61 S)

Seasonal change of phytoplankton (spring vs. summer) in the southern Patagonian shelf

“…These diatom species are also found in Antarctic waters (Gonçalves-Araujo et al, 2015), indicating that Antarctic and subantarctic communities have an important influence on the southern Patagonian region, through advection of subantactic water from the shelf-break region (Olguín et al, 2006;Olguín and Alder, 2011;Gonçalves-Araujo et al, 2012;Olguín Salinas et al, 2015). Such predominance of diatoms in spring has been described for other domains across the Argentine Sea such as the northern shelf, in the La Plata outflow region (Carreto et al, 2008), shelfbreak (Olguín et al, 2006;Garcia et al, 2008;Segura et al, 2013), farther offshore (Olguín et al, 2006;Olguín Salinas et al, 2015) and in subantarctic waters at the Brazil-Malvinas Confluence (Gonçalves-Araujo et al, 2012). Moreover, it is a tenet of phytoplankton ecology that the dominance of fast growing diatoms in temperate latitudes is mainly related to water column structure, through the establishment of sunlit surface waters containing winter-accumulated nutrients, which triggers massive spring phytoplankton blooms (Sverdrup, 1953).…”

Diversity of the diatom genus Fragilariopsis in the Argentine Sea and Antarctic waters: morphology, distribution and abundance

“…F. ritscheri has been reported as a marine planktonic diatom restricted to the southern cold water region (Hasle and Syvertsen 1997). Romero and Hensen (2002) reported this species in high concentration in surface sediments of the Southwestern Atlantic Ocean at 37853 0 S-51841 0 W and at 47896 0 S-56818 0 W. Moreover, it was observed as one of the dominating species during a peak in chlorophyll a concentration recorded in this area (37815 0 S-51823 0 W, Olguín et al 2006). In our samples, F. ritscheri was associated with water temperature and salinity ranges of -1.60 to -0.09°C and 33.17-34.24 psu, respectively.…”

“…F. kerguelensis is a marine planktonic diatom present in the southern cold water region (Hasle and Syvertsen 1997) and is considered an important contributor in the global silicon cycle of the iron-limited Southern Ocean (Cortese and Gersonde 2007). In the Southwestern Atlantic Ocean, the species has been found to dominate diatom assemblages in both water column and sediments (Romero and Hensen 2002;Olguín et al 2006). Frenguelli and Orlando (1959 = F. antarctica/ F. antarctica var.…”

“…However, F. pseudonana (Hasle) Hasle is a cosmopolitan species, and F. doliolus (Wallich) Medlin and Sims is restricted to warm waters (Hasle 1976;Medlin and Sims 1993;Hasle and Syvertsen 1997). Some Fragilariopsis species are found in the Southwestern Atlantic Ocean (Brandini et al 2000;Romero and Hensen 2002;Olguín et. al 2006), but their occurrence in Argentine shelf waters is poorly documented (Ferrario and Galván 1989;Vouilloud 2003).…”

Transformation of iodate to iodide in marine phytoplankton driven by cell senescence

“…For full taxonomic names see Table 1 senescence and cell permeability, and we speculate that it may be linked to internal sulphur species. If, for example, 10 5 diatom cells l -1 -these organisms being present in a range from 10 4 to 10 6 cells l -1 in the Southern Ocean (Kopczynska et al 1986, Olguin et al 2006 -produced iodide at a rate we measured for our Antarctic species (average rate: 3.2 × 10 -7 nmol l -1 cell -1 d -1 ), their total iodide contribution would be 0.0316 nmol l -1 d -1 .…”