Sesional Variatios in the metabolism of a pampean Shallow Lake

MARIA LUZ PADULLES; ADONIS GIORGI; EDUARDO ZUNINO; ANA TORREMORELL

Silber Bay

Workshop; Global Lake Ecological Observatory Network; 2022

National Science Foundation

The shallow lakes in a pampean region has importance to the local economics activities and represent the typical “postcard picture” of the Pampas landscape. Pampean region has 10500 shallow lakes with a size around 0.5 and 10 h. We analyze the metabolism, the effects of nutrients dynamics and picoplankton and phytoplankton composition in a typical pampean shallow lake, Laguna de Lobos. Free-water metabolism were estimated using an optical sensor and the data were recorded every 5 minutes for 6 days during 20 months. Nutrients and other physical and chemical parameters was measured once every mont. Where taken quantitative samples of planckton too and employed Dapi techniques for picoplackton.Metabolic variables (GPP, NME y R) have significant differences between autumn and summer. The principal correlation for GPP with SRP and the principal correlation of the R was negative with pH. The variables that significant difereces we used to carried out a discriminant analized. This analysis could classify adequately the variables in the differents seasons. The variables that where used in this differentiation were: hydrometric level, SRP and SPIM the first function and TN, R and SPOM at the second ones. The predominance algae are filamentous cyanobacteria.The partial conclusions in this shallow lake dominance the autotrophic metabolism in spring and heterotrophy metabolism at the other seasons. In the annual cycle predominance the heterotrophic metabolism. The principal variables which drive the metabolism responses are SRP and SPIM in the case of GPP and organic matter, chlorophyll and TN in the R case.