Phytoplankton of the Río de la Plata estuary

Abstract

The Río de la Plata is an extensive, shallow, and microtidal coastal-plain estuary on the east coast of South America. The river receives freshwater from South America’s second largest watershed. The main tributaries are the Paraná and Uruguay rivers, characterized by fl ows with opposing patterns of seasonal variability. The dynamics of the Rio de la Plata Estuary is controlled by tides, wind-driven waves, and continental runoff. This ecosystem is of great socioeconomic importance since industrial and urban areas throughout the region affect the aquatic habitats. Furthermore, this river is used for several purposes, including drinking water, recreational and navigational activities, but at the same time it receives agricultural runoff and industrial and domestic wastes. The ecology of the phytoplankton of the Rio de la Plata has been only scarcely explored, particularly those organisms relating to the freshwater tidal zone. The work reported here, investigated the principal abiotic conditions that infl uence the composition and distribution of phytoplankton, as well the life-form strategies of the algae along the fl uvial-mixohaline axis. The structural characteristics such as taxonomic groups, species richness, density, biomass, diversity, and size are described. Upon consideration of the availability of nutrients and the residence time of the water within the ecosystem, the risk of the spread of blooms is also analyzed.