Composition and abundance of the mesozooplancton in Sauce Grande shallow lake (Buenos Aires Province, Argentina)

Abstract

El objetivo del estudio fue analizar la composición y abundancia del mesozooplancton en la laguna Sauce Grande (Provincia de Buenos Aires, Argentina) durante el invierno y primavera (Hemisferio Sur) de 2010. Las muestras se colectaron mensualmente en tres estaciones, utilizando una red cónica de 200 μm de poro. El zooplancton estuvo representado por siete taxa. La abundancia varió entre 15,9±0,15 (agosto) y 71,7±31,77 ind/L (noviembre). Los grupos mejor representados fueron Copepoda y Cladocera, siendo Boeckella poopoensis y Moina micrura las especies dominantes respectivamente. Copepoda dominó en los meses más fríos del año mientras que Cladócera, lo hizo sobre fines de primavera. Esto último, podría asociarse a la marcada estacionalidad que experimenta la región.Palabras clave: Mesozooplancton, Laguna Sauce Grande, Argentina. AbstractComposition and abundance of the mesozooplancton in Sauce Grande shallow lake (Buenos Aires Province, Argentina)

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

“…According to [1] this could be explained by the relatively rapid respiration by bacteria and zooplankton of the newly produced organic matter within the lakes. This could be the case in both lakes as high abundances of zooplankton for LS (up to 1300 ind L −1 ), bacteria (up to log 10 3.89 colony formation units (CFU)), and mesozooplankton (up to 100 ind L −1 ) for SG are cited in previous studies [13,35,37]. In other studies, GPP and R were are also coupled and positively correlated as in this case [6,8,16].…”

“…Finally, according to Scheffer's stable states theory [31], LS is in a clear state during the whole study period and dominated by the presence of charophytes which prevent the resuspension of sediments [13], whereas SG is in a turbid state during the whole study period and dominated by phytoplankton [36,37,67]. It is well known that solar light promotes primary production (GPP) and the later the respiration processes (R) that occur within a lake ecosystem [68].…”

“…Water is released downstream only when the dam is full [41]. The SG lake is polymictic, rich in dissolved oxygen, turbid, and eutrophic, with an average concentration of Chl a of 171 µg L −1 [37,39]. It is a large and elongated depression, with low coasts with smooth slopes (usually muddy and with reeds on the northern side), while a coastal dune system controls the southern coast.…”

“…La Salada (LS) is an endorreic, mesosaline, mesotrophic to eutrophic lake that has been studied in recent years for its ecosystem metabolism [7], plankton community [13], and ecosystem services [33]. Sauce Grande (SG) is a flushing, hyposaline, and eutrophic lake that has been studied for its hydrology [34], water quality [35], and plankton community [36,37]. Therefore, we hypothesized that (1) water management will influence ecosystem metabolism with the increment of GPP and R rates through nutrients, DOC, and organic matter loadings from the catchment in both lakes, and (2) that the different salinity, trophic status, and hydrological functioning will result in contrasting metabolism conditions for both lakes.…”