Limnological changes in two shallow lakes from an urban reserve troughout a complete hidrological cycle: proposals for restauration and management

RODRIGO SINISTRO; BUITRAGO GIRALDO S.; RENNELLA A.; MAMANI A.; IRINA IZAGUIRRE

International Journal of Environment and Health

Inderscience Publishers

Lugar: Olney; Año: 2012 p. 1 - 27

1743-4963

We analysed the fluctuations of the limnological variables and phytoplankton structure in two shallow lakes located in an urban ecological reserve from Buenos Aires city (Reserva Costanera Sur) during a complete hydrological cycle. The studies started at the end of a dry period when the water levels of the shallow lakes were extremely low, and we analysed the changes throughout the period of rising waters and posterior water decrease until the complete drought of the lakes. The results of this investigation showed that the changes in the water level strongly affect the limnological variables and the structure of the phytoplankton communities. In both shallow lakes the water level was inversely correlated with conductivity (p < 0.05). During the rising waters, a progressive colonization by floating macrophytes was observed, but with different percentage of coverage in both lakes; the macrophyte-cover affected the dissolved oxygen concentrations, registering very low values under profuse plant coverage. With respect to phytoplankton, we analysed the fluctuation of the algal groups and dominant species, evaluating the changes in the structure in the context of the phytoplankton functional groups, and we observed that the water level was one of the main variables explaining the variations in the community. We propose some alternatives for the management and restoration of the shallow lakes of this reserve.