INVESTIGADORES
RODRIGUEZ patricia laura
artículos
Título:
Water level variation as the main driver of the alternation between a free-floating plant and a phytoplankton dominated state: a long term study in a floodplain lake
Autor/es:
O`FARREL, I.; IZAGUIRRE, I.; CHAPARRO, G.; UNREIN, F.; SINISTRO, R.; PIZARRO, H.; RODRÍGUEZ, P.; DE TEZANOS PINTO, P.; LOMBARDO, R.; TELL, G.
Revista:
AQUATIC SCIENCES
Editorial:
BIRKHAUSER VERLAG AG
Referencias:
Año: 2011 vol. 73 p. 275 - 287
ISSN:
1015-1621
Resumen:
This 10-year field data study explores the relevance
of water level fluctuations in driving the shift from a
free-floating plant (FFP) to a phytoplankton dominated state
in a shallow floodplain lake from the Lower Parana´ River.
The multi-year natural flood pulse pattern in the Lower Parana
´ River drove the ecosystem regime from a FFP-dominant
state during very high waters (19981999) to absolute phytoplankton
prevalence with blooms of nitrogen fixing
Cyanobacteria during extreme low waters (20082009).
Satellite images support the observed changes over the
decade and show the decrease of the surface lake area covered
by FFP as well as the modification of the spectral firm in
open waters, which documents the significant increases in
phytoplankton chlorophyll a concentrations. We discuss the
possibility that, despite a slow eutrophication in these highly
vegetated systems, water level changes and not nutrients
account for the shift from a floating macrophyte community
to phytoplankton dominance. Cyclic shifts may occur in
response to the seasonal floodpulse, but more strongly, as
indicated by our results, in association to the extreme drought
and flood events related to the El Nino Southern Oscillation,
which is linked to discharge anomalies in the Parana´ River.
possibility that, despite a slow eutrophication in these highly
vegetated systems, water level changes and not nutrients
account for the shift from a floating macrophyte community
to phytoplankton dominance. Cyclic shifts may occur in
response to the seasonal floodpulse, but more strongly, as
indicated by our results, in association to the extreme drought
and flood events related to the El Nino Southern Oscillation,
which is linked to discharge anomalies in the Parana´ River.
possibility that, despite a slow eutrophication in these highly
vegetated systems, water level changes and not nutrients
account for the shift from a floating macrophyte community
to phytoplankton dominance. Cyclic shifts may occur in
response to the seasonal floodpulse, but more strongly, as
indicated by our results, in association to the extreme drought
and flood events related to the El Nino Southern Oscillation,
which is linked to discharge anomalies in the Parana´ River.
a concentrations. We discuss the
possibility that, despite a slow eutrophication in these highly
vegetated systems, water level changes and not nutrients
account for the shift from a floating macrophyte community
to phytoplankton dominance. Cyclic shifts may occur in
response to the seasonal floodpulse, but more strongly, as
indicated by our results, in association to the extreme drought
and flood events related to the El Nino Southern Oscillation,
which is linked to discharge anomalies in the Parana´ River.