Una interpretación de los factores que influyen sobre la variabilidad de la alcalinidad en el Río Paraná medio (Argentina)

Abstract

The multinational Paraná River (drainage basin, ~2.6 10<SUP>6</SUP> km<SUP>2</SUP>; annual discharge, ~500 km<SUP>3</SUP> y<SUP>-1</SUP>) has a long (~900 km) and wide (~30 – 50 km) flood valley, which occupies its middle and lower stretches. Most of the valley’s area (estimated area of ~50000 kmkm<SUP>2</SUP>) holds a myriad of ponds, ox-bows, and channels which, following the seasonal variation of the prevailing discharge regime, exchanges water, dissolved species, sediment, and biological materials with the Paraná’s main stem. Exceptional hydrological events (e.g., ENSO-triggered) flood almost totally the expanse of the flood valley. A ten year-long (1965 – 1975) continuous series of alkalinity measurements allowed probing into the mechanisms that determine the observed alkalinity variability -controlled by several biogeochemical processes (e.g., photosynthesis/respiration, nitrification/denitrification, etc.) occurring in the riparian environment-, which are associated with the Paraná’s hydrological stage.