INALI   02622
INSTITUTO NACIONAL DE LIMNOLOGIA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Spatiotemporal gradients in the Paraná River-Floodplain System from a plankton functional approach
Autor/es:
DEVERCELLI, M.; JOSÉ DE PAGGI, S.; PAGGI, J.C.; GARCÍA DE EMILIANI, M.O.
Lugar:
Natal
Reunión:
Congreso; XIII Congreso Brasileiro de Limnologia; 2011
Resumen:
The
plankton of the Middle Paraná River System was studied in order to analyse the
community driving forces and the ecological effects of different hydrological periods
in the lateral dimension using a functional approach. Phytoplankton and zooplankton biomass and limnological variables
(hydrological, physical and chemical parameters) were studied at the mainstem,
secondary channel and two floodplain lakes during the periods 1974-1975,
1986-1988, 1997-1998 and 1999-2000, covering ordinary and extreme hydrological
phases.
A
spatial gradient with an increasing phytoplankton and zooplankton biomass from the
mainstem to the more isolated water bodies was observed. In the mainstem and
secondary channel, a predominance of P and C phytoplankton functional groups,
adapted to the turbulent and turbid conditions of the rivers, was found. A high
diversity of functional groups, and coda composed by species with low growth
rate (H1, W1, W2) were observed at the floodplain lakes. The zooplankton was
characterised by the progressive increase
of the larger species (cladocerans and copepods) along with the environmental
gradient from low to high water residence time. The temporal gradient indicated structural
changes and an inverse relationship between plankton biomass and water discharge.
Drought periods favoured plankton development, except at the mainstem where the
exchanges of organisms with the floodplain are essential for plankton
maintenance.
In
conclusion, the spatiotemporal changes of the plankton community are associated
to the hydrosedimentological regime. As the lentic habitats are isolated from
the lotic influence, zooplankton increases its role as phytoplankton control
factor, so that biotic interactions became progressively more important in the
community dynamics.
FINANCTIAL
SUPPORT: Proyecto PICT Bicentenario (ANPCyT-FONCyT) y Proyecto SECTeI
2010