Influence of climate and environmental variability on phytoplankton dynamics in the spring reproductive area of Engraulis anchoita (Southwestern Atlantic Ocean)

M. MARRARI; S. SIGNORINI; C. MCCLAIN; M. PÁJARO; M.D VIÑAS; DIMAURO, R; CEPEDA, G. C.

Venecia

Simposio; Ocean from Space Venice 2010; 2010

IWWG - International Waste Working Group

The main spring reproductive area of the Argentine anchovy, Engraulis anchoita includes a coastal thermal front established in the vicinity of the 50m  isobath characterized by elevated spring phytoplankton abundances. We use a 12-year time series of SeaWiFS ocean color data to investigate chlorophyll  a dynamics in relation to climate and other environmental influences. During spring, chlorophyll concentrations were most influenced by the Southern Annular Mode (SAM) and sea surface temperature (SST), with negative phases of SAM and colder surface waters resulting in above-average chlorophyll a concentrations. In addition, interannual variability in chlorophyll a concentrations had a significant effect on zooplankton populations and reproductive success of E. anchoita. We discuss the mechanisms by which large scale climate phenomena may influence local populations in the Southwestern Atlantic Ocean.