Environmental evaluation of the Northern Argentine Sea (South-Western Atlantic Ocean, 35°-42°S).

JORGE MARCOVECCHIO; SILVIA DE MARCO; ANDREA GAVIO,; MAITE NARVARTE; SANDRA FIORI; MARCELA GERPE; DIEGO RODRÍGUEZ; MARÍA CELESTE LÓPEZ ABATTE; NOELIA LA COLLA; ANA LAURA OLIVA; SERGIO ZALBA; MARÍA CIELO BAZTERRICA; VALERIA GUINDER; CARLA SPETTER; MELISA FERNANDEZ SEVERINI; ANDRES ARIAS; SANDRA BOTTE

World Seas: An Environmental Evaluation, Vol I: Europe, The Americas and West Africa

ELSEVIER SCIENCE BV

Lugar: Londres; Año: 2019; p. 759 - 781

The Northern Argentine Sea is part of the Southwestern Atlantic Ocean, extending from ~35°S to 42°S (Fig. 33.1). The continental shelf is with a very low relief and a general slope of less than 0.01 degree (Cavallotto, Violante, & Hernández- Molina, 2011). Argentina?s continental margin is longer than 3500 km, with an average width of ~400 km (Preu, Hernández- Molina, Violante, Piola, et al., 2013). It originated during the Late Jurassic-Early Cretaceous (c.140 My ago), when the opening of the South Atlantic took place (Marcovecchio, De Marco, & Melo, 2017). The width of the shelf within this area varies from ~140 km in the northern area of Río de La Plata outfall, to ~540 km at San Matías Gulf (SMG), with maximum depth of 70?80 m, reaching ~200 m at the shelf edge, to ~160 m within the SMG (Mouzo, 2014).The main oceanographic features are the encounter of the Brazil and Malvinas/Falkland currents (MCs), producing the Brasil-Malvinas/Falkland Confluence Zone (BMCZ), a complex of mixed waters located between 35°S and 40°S. This re- gion is marked by a strong front formed by the warm, high saline, and low productivity waters of the Brazil Current (BC), and the cold, less saline, and highly productive waters of the MC, and is characterized by intense horizontal and vertical mixing and a seasonal pattern of current intensification and latitudinal instability (Piola, Campos, Möller Jr., Charo, & Martinez, 2000). In the confluence zone, the subantarctic and subtropical waters mix, forming vortices, meanders, and strong vertical and horizontal temperature and salinity gradients, as well as restricted areas of enhanced chlorophyll build-up, isolated up- welling cells, tongues, and patches of cold or warm waters partly or completely isolated from their water mass of origin, and so on. South of 37°S, three water masses are identified: shelf break (outer shelf) water of relatively high salinity (33.7?34), middle shelf water with relatively low values (33.4?33.6), and coastal (inner shelf) waters with values relatively higher (>34).