Published 4 issues per year
ISSN Print: 1521-9429
ISSN Online: 1940-4328
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Species diversity of phytoplankton in waters of the Argentine Islands (Antarctic regions)
ABSTRACT
Results of studies on species diversity of phytoplankton are presented for the waters of Argentine Islands. Seasonal variations in the community species composition have been described; the dominant species and taxa, and the time periods of their vegetation were identified for the first time in the waters of Argentine Islands. In total, 151 microalgal species (157 infraspecific taxa) referring to eight taxonomic divisions were recorded. Bacillariophyta 95 (101 infr. taxa) and Dinophyta (34) were the most species-rich divisions, while the others were represented by 1 to 8 taxa only. The highest species diversity was registered in spring and early summer. Three main peaks of the phytoplankton abundance occurred annually during the spring-summer period, which included the populations of Phaeocystis pouchetii (Chrysophyta) in October, the diatom genera Fragilariopsis, Achnanthes and Corethron in November and early December, and bloom of Cryptomonas sp., Pyramimonas sp. and other small flagellates in the middle of January. Changes in the list of the dominant species as well as their abundance and size distribution corresponded to the 1st- 3rd stages of the spring-summer succession. In autumn and early polar winter, when the phytoplankton vegetation gradually disappears, the quantity of plant cells in plankton and their species diversity are indeterminant.