Bathymetry and Morphometry of Pampean Shallow Lakes: An Approach to the origin and productivity.

VITALE, A. J.; SEITZ, C.; PICCOLO M. C.; PERILLO, G.M.E.

Workshop; GLEON XVIII Global Lake Ecological Monitoring Network; 2016

GLEON

Lake productivity is determined by three principal factors, lake morphology, climatic conditions and watershed?s soil characteristic. In this study, the morphometric characteristic of two Pampean shallow lakes is analyzed. La Salada (39°27'45.27"S - 62°42'10.89"W) and La Barrancosa (37°20'13.17"S - 60° 6'33.95"W) are located in the Buenos Aires Province, Argentina. The objectives were: determine the origin of these shallow lakes based on morphometric characteristic related with regional geomorphology; analyze the dynamics between the morphometric characteristics and the external and internal factors (climatic variability, wind, etc; suspended solids, zonation, etc.); to analyze how slight differences in morphometry drives different responses in these shallow lakes which have a similar origin.A bathymetry was made using an open source acoustic profiler installed over an autonomous small boat. The track and the acoustic profiler were recorded at 5 Hz. The bathymetric maps and morphometric analyses were made using GIS software. The morphometric analyses were made following the Hakånson (1981, 2004, 2012), Timms (1992), and Contreras (2011) criteria. The morphometric parameters indicate an eolic origin for both shallow lakes. The Barrancosa's mean depth euphotic zone is lower than La Salada. Despite this, Barrancosa is less affected by the resuspension of sediment than La Salada. The study shows that the morphologic factor is responsible for changes these shallow lakes. The results show that small depth changes could affect the ET- area and consequently the lake productivity.