nutrients flux in a pampean shallow lake, Argetina

PADULLES M. L.; GIORGI, ADONIS; ZUNINO, E.; TORREMORELL, A. M.

Foz do Iguazú

Congreso; SIL International Congress of Limnology; 2024

Society International of Limnology

The shallow lakes of the Pampas plain, Argentina, have been suffering from eutrophication for several years. With the intensification of agriculture in the region, most of the shallow lakes are in an organic turbid state. With the purpose of describing a balance of inputs and outputs of nutrients in a typical Pampas shallow lake, we study inputs: runoff, upstream inflows and groundwater; and outputs: downstream outflows in “Laguna Lobos” for two years. “Laguna Lobos” acts as a nutrient sink, where the most important nutrient input is from the main upstream “Las Garzas”. In one year, 85 tons of P, more than 700 tons of organic particulate matter, 10 tons of N-NH4, and 3.7 tons of NO2 accumulate in the shallow lake, but exports 20 tons of NO3. The data show the imminent clogging that the shallow lakes of the Pampas could suffer, causing the disappearance of shallow lakes, more than 10,000. The largest contributor to eutrophication is the “Las Garzas” stream, which collects runoff from its banks. It is important to prevent future nutrient inputs coming from Las Garzas stream than those coming from surrounding fields. By improving the quality of the streams in the Pampas region, the eutrophication rates of the shallow lakes would be reduced.