Abstract

ZAPLARA, Virginia S; SOLARI, L. C; BENITEZ, Hernán H  and  GABELLONE, N. A. Microorganismos consumidores en suelos de la llanura de inundación del arroyo El Pescado (Buenos Aires): Experiencia en microcosmos. Rev. Mus. Argent. Cienc. Nat. [online]. 2018, vol.20, n.2, pp.311-322. ISSN 1853-0400.

The periodic flooding in large rivers basin favors that the organisms colonize the floodplain. Colonization events can occur in days or weeks and many species through their resistance structures can remain in the soil after a flood event. The objective of this work was to analyze the succession of microconsumers from soil samples taken from the floodplain of the El Pescado stream (Buenos Aires). Five treatments were performed with three replicates each exposed to different waterlogging times. Temperature, conductivity, dissolved oxygen, pH and turbidity were measured in each experimental unit. Likewise, the concentration of total phosphorus, total dissolved phosporus, chlorophyll “a” were estimated and the quantitative analysis of the organisms was carried out. Thirty taxa were recorded and ciliates (9), testate amoebas (8) and rotifers (8) were better represented. The ciliates had their maximum density in the initial stage with Urocentrum turbo as dominant. The testate amoebas dominated in the final stage with Arcella and Difflugia species. The bdelloid rotifers were always present and the monogononta reached their maximum density (Lecane lunaris and Plationus patulus) towards the end of the experiment. The copepods were observed from the initial stage with larval stages and, in the final stage, with cyclopoid and harpacticoid adults (Attheyella sp. and Cletocamptus sp.). Bacterivores predominated in the initial stage, filter feeders and grazers intermediate, and detritivores to the end. The presence of the different groups in the treatments was related to their generational times and to the simulated hydroperiod.

Keywords : Pampean stream; Floodplain; Waterlogged soil; Microorganisms; Colonization; Microcosms.