INVESTIGADORES
RODRIGUEZ patricia laura
congresos y reuniones científicas
Título:
State shifts in a shallow lake subject to marked water level changes
Autor/es:
O´FARRELL, I.; IZAGUIRRE, I.; CHAPARRO, G.; UNREIN, F.; SINISTRO, R.; PIZARRO, H.; RODRÍGUEZ, PATRICIA; DE TEZANOS PINTO, P.; LOMBARDO, R.; TELL, GUILLERMO
Lugar:
Cape Town, Southafrica
Reunión:
Congreso; 31st Congress of the International Limnological Society, Cape Town, South Africa; 2010
Institución organizadora:
SIL
Resumen:
We explore the relevance of water level fluctuations in driving the shift from a free-floating plant to a phytoplankton turbid state dominated by Cyanobacteria in a shallow South American nutrient rich floodplain lake. The multi-year natural floodpulse pattern in the Lower Paraná River led the ecosystem from a dominance of native free-floating plants during very high waters (1998-1999) to total phytoplankton supremacy during extreme low waters (2008-2009). Phytoplankton at the initial phase was characterised by small Chlorococcales, Chroococcales and centric diatoms, Cryptophyta, Dinophyta and Euglenophyta. At the late drought stage, which coincided with an ENSO event (La Niña), Cyanobacteria dominated the phytoplankton assemblage strongly decreasing the typically high phytoplankton diversity of this lake. The final replacement of shade adapted colonial and filamentous blue-green algae by a bloom of actively nitrogen fixing Nostocales is analysed.