title: Influence of El Niño Southern Oscillation phenomenon on coastal phytoplankton in a mixohaline ecosystem on the southeastern of South America: Río de la Plata estuary.
abstract: The aim of this study was to analyze the density, diversity, biomass and assemblage composition of the phytoplankton in relation to environmental conditions (physical, chemical, hydrological and meteorological variables), measured under the different scenarios caused by the ENSO phenomenon in the period between 2005 and 2012, in six sampling sites in the tidal freshwater zone of the Río de la Plata estuary, covering almost 100km of coastline. The results revealed changes in the structure of the phytoplankton, such as a significant reduction of diversity, and decreases in biomass and phytoplankton density, particularly during El Niño phases. Cyanobacteria were more abundant in the neutral periods, Chlorophyceae dominated La Niña phase while Bacyllariophyceae dominated El Niño. However, no complete replacement of species between cycles was observed. The results obtained were highly variable due to the inherent natural variability of the Río de la Plata, emphasized by the anthropogenic impact in this area.
authors.affiliation: Instituto de Limnología "Dr. Raúl A. Ringuelet", Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Argentina; CONICET-Consejo Nacional de Investigaciones Científicas y Tecnológicas, Argentina.
authors.forename: María Belén
authors.initials: MB
authors.lastname: Sathicq
authors.affiliation: Instituto de Limnología "Dr. Raúl A. Ringuelet", Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Argentina; Comisión de Investigaciones Científicas de la Provincia de Buenos Aires, Argentina.
authors.forename: Delia Elena
authors.initials: DE
authors.lastname: Bauer
authors.affiliation: Instituto de Limnología "Dr. Raúl A. Ringuelet", Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Argentina; CONICET-Consejo Nacional de Investigaciones Científicas y Tecnológicas, Argentina. Electronic address: nora@ilpla.edu.ar.
authors.forename: Nora
authors.initials: N
authors.lastname: Gómez
mesh_terms: D001118:Argentina; D000458:Cyanobacteria / Q000502:physiology; D017753:Ecosystem; D059000:El Nino-Southern Oscillation; D063366:Estuaries; D005618:Fresh Water; D062070:Hydrology; D010839:Phytoplankton / Q000737:chemistry; D013020:South America
keywords: El Niño Southern Oscillation phenomenon; Freshwater tidal zone; Phytoplankton; Río de la Plata estuary; Structural responses