Drivers of Ecosystem Metabolism in Two Managed Shallow Lakes with Different Salinity and Trophic Conditions: The Sauce Grande and La Salada Lakes (Argentina)

ALFONSO, MARÍA; BRENDEL, ANDREA; VITALE, ALEJANDRO J.; SEITZ, CARINA; PICCOLO, MARÍA; PERILLO, GERARDO

Water

MOLECULAR DIVERSITY PRESERVATION INTERNATIONAL-MDPI

Año: 2018 vol. 10

Understanding the drivers and how they affect ecosystem metabolism is essential fordeveloping effective management policy and plans. In this study, net ecosystem production (NEP),ecosystem respiration (R), and gross primary production (GPP) rates were estimated in relation tophysicochemical, hydrological, and meteorological variables in La Salada (LS) and Sauce Grande(SG), two shallow lakes located in an important agricultural region with water management.LS is a mesosaline, mesotrophic-eutrophic lake, whereas SG is a hyposaline and eutrophic lake.GPP and R showed daily and seasonal variations, with R exceeding GPP during most of thestudy period in both lakes. Net heterotrophic conditions prevailed during the study period (NEPLS: −1.1 mmol O2 m −2 day −1 and NEP SG: −1.25 mmol O2 m −2 day −1). From data analysis,the temperature, wind speed, and lake volume are the main drivers of ecosystem metabolismfor both lakes. Despite the significant differences between the two lakes, the NEP values were similar.The different hydrological characteristics (endorheic vs. flushing lake) were crucial in explaining whythe two different systems presented similar ecosystem metabolic rates, emphasizing the importanceof water management.