IWRA Proceedings

AbstractThe Laguna del Plata is located in the Southwestern zone of the Mar Chiquita Lagoon, to the northeast of the province of Cordoba in the Argentine Republic. The Laguna del Plata is part of the most complex hydrological closed system and of the major salty lake of South America, constituting an area of important biological value, declared a Reserve of Multiple Uses by the province of Cordoba. In the international level, it has been denominated ”Site of Hemispherical Value” by the Western Hemisphere Shorebird Reserve Network, it is part of Living Lakes’ international network and it has been declared "Wetland of International Importance" by the RAMSAR convention. Nevertheless in spite of its importance, its study degree or its level of knowledge is quite limited. The clear existence of a deficit in the knowledge of the hydrodynamic behavior and in the water quality of the proposed system; together with its importance as a regional, environmental and economic resource, justifies the selection of this case of investigation, and the special interest on the evaluation of the water quality in this system. The Laguna del Plata has a surface of approximately of 20 km²; in dry periods is connected through a channel to the Mar Chiquita lagoon, whereas in humid periods it is transformed into a bay. In 1970, they did not have any hydrological connection, and among them existed significant differences in salinity terms. At the present time, in the lagoon is only allowed sport fishing and recreational activities. The aim of the present work is to evaluate the water quality of the Laguna del Plata, considering the inflow of nutrients that receives from its tributary, the Primero river (also named Suquía), and the influence that the Mar Chiquita Lagoon has on it. Nowadays seasonal monitorings are carried out in five points on lagoon and two on the Primero river (Suquía), selected according to the morphologic characteristics of the system in study. The measured physical-chemical parameters are Majority Ions, salinity, Total Phosphorus (TP) and Soluble Reactive Phosphorus (SRP), Suspended Material, Turbidity, Chlorophyll-a and Phytoplankton. The analyzed parameters were interesting for the chemical characterization of the lagoon’s water, which was classified as salty, sodium chlorinated. The inflow of TP and SRP from the Primero river (Suquía) are important, lowering considerably their concentration in the lagoon due possibly to the chemical properties of the above mentioned compounds in saline water. In the slow-flowing water mass, certain variability was observed when evaluating the spatial and temporary distribution of the TP, SRP, Chlorophyll-a, and the Phytoplankton’s composition.