The Continental Shelf of the South-Western Atlantic Ocean

Abstract

The continental shelf of the South-Western Atlantic Ocean (SWAO), which includes the area between 33 and 55◦S adjacent to the southeast South American continent (Fig. 5.4.1), is a wide, open shelf highly impacted by two major western boundary currents: the Malvinas (Falkland) Current and the Brazil Current. Strong winds blowing off the continent are also important in the nearshore region. The SWAO is a very important oceanographic region with significant exchange of materials between ocean and continent passing through coastal and estuarine systems. This continental shelf has an extreme variability not only due to the responsiveness to the passage of weather systems but also because river runoff, the meandering boundary currents and synoptic mesoscale eddies from the open ocean impinge on the continental margin entraining waters from the coastal ocean (Piccolo,1998). Little is known about the circulation, dynamics, physical and biogeochemical processes, because of the varied time and space scales over which processes occur (Piccolo, 1998). The goal of this review is to provide an updated knowledge on the nutrient distributions within the SWAO continental shelf, as well as their transport and transformation, and the nutrient input from land sources. The environmental characteristics of the region (e.g. geomorphology, sedimentology, hydrography) are summarized. In addition, a description of the nutrient and chemical environment, as well as data on primary productivity and carbon transfer within the area are included. Finally, the riverine transfer of carbon and nutrients to the S.W.Atlantic is also considered.