Cross-frontal distribution of inorganic nutrients and chlorophyll-a on the Patagonian Continental Shelf of Argentina during summer and fall

Oceanographic data collected during 2001-2003 on the Patagonian Continental Shelf of Argentina were analyzed in order to study the main chemical features of this large shelf. The variation of inorganic nutrients and chlorophyll-a during summer and fall in an area within 40 to 60 km from the coast are presented. Nitrate is the limiting nutrient in the region and is negatively correlated to chlorophyll-a. All variables show localized variations in summer, which can be related to tidal fronts through the comparison of our data with the critical Simpson parameter of stability (50 J m^-3). In fall, nutrient concentrations on the continental shelf were more uniform and generally higher than in summer due to the disruption of these fronts.