The Bahia Blanca estuary in a regional context

Abstract

The aim of this introductory chapter is to provide the readers some insight into the regional context of the Bahia Blanca Estuary. We begin this chapter with a description of the geological settings along the Atlantic coast of South America. Central to this issue is the evolution of the relative sea level during the Holocene, which shaped the landscape structure of major coastal wetland systems. Regarding the regional climate, central east Argentina is characterized by a large interannual rainfall variability and by a strong gradient of decreasing rainfall from the northeast to the southwest. Vegetation types along this area are strongly associated with the regional precipitation gradient, ranging from grasslands in the northeast to xerophytic shrublands and bushy steppes in the southwest. In the marine realm, the Bahia Blanca Estuary belongs to the Large Marine Ecosystem called Patagonian Shelf, characterized by the extensive mixing of the Malvinas and the Brazil Currents. El Rincon, in the coastal zone off the Bahia Blanca Estuary, is a highly productive area due to the occurrence of elevated densities of fish and zooplankton. The availability of adequate food, suitable thermal and salinity ranges, and the oceanic circulation that favors a retention mechanism would facilitate fish larval recruitment and growth of valuable commercial species.