Phytoplankton from the Southern Coastal Fringe of the Río de la Plata (Buenos Aires, Argentina)

摘要: Structural characteristics of spring phytoplankton from the Southern Coastal Fringe Rio de la Plata between 58°32′ and 57°41′ W, up to 10 km coast line are analysed. From 126 recorded taxa, 69 had a relative frequency above 5%. Main frequencies coincided with main quantitative abundances, corresponding centric diatoms genus Aulacoseira – A. granulata var. augustissima especially Stephanodiscus hantzschii coccal green Dictyosphaerium pulchellum D. subsolitarium; exception was Cyanophyceae Microcystis aeruginosa, which showed greatest abundance, but not among most frequent species. Centric accounted for biovolume. Average density 259 cells ml-1 (11–3700 ml-1). Diversity index (H′) varied 0.51 2.78 bits ind-1. Phytoplankton size structure was: 43% picoplankton, 56% nanoplankton 1% microplankton. Quantitative data on selected species were assessed similarity stations, 74% joined in group dominated by sp. pl. codominated algae. The groups aeruginosa included stations affected pollution. Algal patchiness following low tide river currents. eutrophic, oligohalophilous mesosaprobic, composition agreement some true potamoplankton.