CECOAL   02625
CENTRO DE ECOLOGIA APLICADA DEL LITORAL
Unidad Ejecutora - UE
artículos
Título:
Phytoplankton of the Paraná River Basin
Autor/es:
DEVERCELLI, MELINA; YOLANDA ZALOCAR DE DOMITROVIC; FORASTIER MARINA E.; NORMA MEICHTRY DE ZABURLIN
Revista:
FUNDAMENTAL AND APPLIED LIMNOLOGY
Editorial:
E SCHWEIZERBARTSCHE VERLAGS
Referencias:
Lugar: Stuttgart; Año: 2014 vol. 65 p. 39 - 65
ISSN:
1863-9135
Resumen:
We summarize the information on the phytoplankton of the Paraná River in the Argentinestretch, comparing the density, biomass, functional groups and diversity studies of the mainstemand fl oodplain since the 70?s. We described the Yacyretá Reservoir and its impact downriver sinceit started operating in 1994. The spatio-temporal changes of the phytoplankton are associated to thehydrosedimentological regime. Regular variations in the hydrological phases and shorter permanentfl uctuations are essential for phytoplankton maintenance, since they allow the lateral exchange withzones of higher algal accumulation in the main channel and with the fl oodplain. During ordinaryhydrological cycles, the mainstem shows a typical potamoplankton, dominated by Aulacoseiragranulata and, alternatively, with sub-dominance of Chlorococcales, Cryptophyceae at the Middleand Lower Stretch, Cyanobacteria abound at Yacyretá Reservoir and downriver at the High and thebeginning of the Middle Stretch. The disruption of Yacyretá Reservoir produces profound changesin the High Paraná phytoplankton evidenced in increased density and replacement of dominantspecies; Cryptophyceae replaced the Bacillariophyceae. Since 2001, water transparency increasedand phosphorus concentration decreased, as well as the density and diversity of phytoplankton. Since2004, an increase in Cyanobacteria was observed with bloom of Microcystis aeruginosa that extended220 km downstream of the dam. Anomalous hydrological cycles, related to the ENSO phenomenonproduced changes in phytoplankton density and structure. During El Niño, the system maintains arelative homogeneous phytoplankton assemblage, although mean density values are signifi cantly lowerthan those registered in ordinary hydrological periods. La Niña provokes a more drastic change inthe community, due to the disruption in the exchange with the alluvial valley. The river-fl oodplainconnectivity is essential for the maintenance of phytoplankton diversity.