river flow Rivers 10 Argentina 8 El Nino-Southern Oscillation 6 Precipitation 6 South America 6 phytoplankton 6 precipitation (climatology) 6 temporal variation 6 Annual rainfall 4 Atmospheric pressure 4 Brazil 4 Cyanobacteria 4 Deforestation 4 Euglenida 4 Evaporation 4 Functional groups 4 Glycine max 4 Hydrological conditions 4 La Nina 4 Land Use 4 Land use 4 Land use change 4 Land-use change 4 Natural forests 4 Nickel Compounds 4 Nickel compounds 4 Northern basins 4 Paraguay 4 Paraguay Basin 4