Coastal environments in the Bahia Blanca Estuary, Argentina

CUADRADO, D.; PIOVÁN, M.J.; PRATOLONGO, P.

Sabkha Ecosystem V: The Americas.

Springer

Año: 2016; p. 205 - 224

The Bahía Blanca Estuary is a coastal system placed in a sharp transition between humid subtropical and semiarid climates, shaped by a unique combination of large interanual climatic variations and a transgressive sea level during the Holocene. In the region, the late Holocene marine transgresion resulted in low coastal landforms inherited from the former estuarine dynamics. These environments are commonly occupied by coastal plainsecosystems that can be roughly classified into intertidal and inland (perimarine) wetlands. Within the intertidal zone, most of the area is covered by extensive barren mudflats, and marshes are dominated by Spartina alterniflora or Sarcocornia perennis. A supralittoral zone can be defined in an intermediate position, irregularly inundated by sea water. Vegetation in this zone is sparse, with a mosaic of salt flats, halophytic steppes and shrubs forming mound-intermound complexes. The Old Marine Plain, in the inland limits of the marine transgression is not affected by tidal flooding, but an irregularly humid zone develops due to saline seepage from the uplands. These wetlands are subjected to episodic disappearance, and may get dry for several years, relying on the occurrence of rainy years during humid periods to resurge. Because of their highly dynamic nature, and the particular climatic settings of the area, these wetlands are sensitive indicators of climate change and variations in large scale circulation patterns. This chapter describes climatic patterns , geomorphological settings, and plant communities, as well as the major physical and biological interactions defining landscape structure