Phytoplankton community during a coccolithophorid bloom in the Patagonian Shelf: microscopic and high-performance liquid chromatography pigment analyses

We describe the phytoplankton community and biomass during a summer coccolithophorid bloom sampled over the Patagonian shelf (48.58S– 50.58S). Those phytoplankton species can contribute to the flux of calcium carbonate out of surface waters. Results from both microscope and high-performance liquid c...

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Bibliographic Details
Published in:Journal of the Marine Biological Association of the United Kingdom
Main Authors: Souza, Márcio Silva de, Mendes, Carlos Rafael Borges, Garcia, Virginia Maria Tavano, Pollery, Ricardo Cesar Gonçalves, Brotas, Vanda Costa
Format: Article in Journal/Newspaper
Language:English
Published: 2011
Subjects:
Coccolithophorids
Patagonian shelf
Phytoplankton community
CHEMTAX
Pigments
Taxonomy
Antarc*
Antarctica
Online Access:http://repositorio.furg.br/handle/1/2109
https://doi.org/10.1017/S0025315411000439
Description
Summary:We describe the phytoplankton community and biomass during a summer coccolithophorid bloom sampled over the Patagonian shelf (48.58S– 50.58S). Those phytoplankton species can contribute to the flux of calcium carbonate out of surface waters. Results from both microscope and high-performance liquid chromatography (HPLC) analysis are shown to complement information on the phytoplankton community. From CHEMTAX analysis of HPLC data, the most important organisms and groups identified were the coccolithophorid Emiliania huxleyi, the haptophyte Phaeocystis antarctica, dino- flagellates, diatoms, cryptophytes, prasinophytes and cyanobacteria. Phytoplankton microscope counts were converted into phytoplankton group-specific biovolume estimates. Although some microscope-identified taxa could not be determined by CHEMTAX, e.g. the autotrophic ciliate Myrionecta rubra, cluster analyses from both techniques showed similar results for the main groups. Both Emiliania huxleyi cell concentration and biomass, and the pigment 19 ′ -hexanoyloxyfucoxanthin were the most important biological features during the sampling period. At surface, nitrate was moderately high (0.2 –4.2 mM) in coccolithophorid-dominated samples, whereas phosphate (,0.33 mM) and silicate (,1.35 mM) concentrations were low. Among the environmental factors low Si:N ratios were mainly associated with the dominance of E. huxleyi. Competition and probably differential grazing could also promote a coccolithophorid outgrowth over other photoautotrophs during the summer season in the Patagonian shelf.

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