Land-sea interface features of four estuaries on the South America Atlantic coast/Caracteristicas da interface continente-oceano de quatro estuarios da zona costeira da America do Sul

• Published in: Brazilian journal of biology Vol. 72; no. 3(SUPPL); pp. S761 - 761
• Main Authors: Bernardes, M.C, Knoppers, B.A, Rezende, C.E, Souza, W.F.L, Ovalle, A.R.C
• Format: Journal Article
• Language: English
• Published: São Carlos Association of the Brazilian Journal of Biology 01.08.2012; Instituto Internacional de Ecologia
• Subjects: anthropogenic impacts; biomas da zona costeira; Brackish; Budgets; Carbon dioxide emissions; Climate change; climate changes; Coastal zone; coastal zone biomes; Dams; Dry season; Estuaries; Freshwater; geomorfologia; geomorphology; Hydrologic cycle; impactos antrópicos; mudanças climáticas; Nitrogen; Plankton; Rainy season; river discharge; Rivers; Seasonal variations; vazão hidrológica; Brasil; ASW, Brazil, Paraiba; South America, Amazon R
• ISSN: 1519-6984; 1678-4375
• DOI: 10.1590/S1519-69842012000400011

The Brazilian coastal zone extends from 4°N to 34°S latitude and because of its long extension, the interface zone from continent to ocean includes a high diversity of geomorphologic and oceanographic characteristics. The rivers from the Northeast and East regions are marked by a typical unimodal seasonal flux patterns but with different amplitudes. As the climate indicates, the rivers from the Northeast are subject to an accentuated seasonal variability with an elevated input and flood pulses during the rainy season and low to negligible fluxes during the dry season. Small-scale rivers usually present typical torrential behaviour. In the humid eastern region, the unimodal seasonal cycle is dampened with a more constant input supply. Recently, some studies have shown that the material supply from rivers along the Northeast and Eastern coasts is diluted by surface tropical waters of oceanic currents and that the estuarine plume dispersal is restricted to a narrow coastal belt. However, human impacts of course mask or even override both natural hydrological cycles and C[O.sub.2] emissions from terrestrial biomes, or depending on the nature of the human impact, can even increase extreme events. Henceforth this contribution addresses the typological, hydrological and biome diversity of the four estuarine systems fed and affected by the respective Amazon, Sao Francisco, Paraiba do Sul and Plata watersheds.