QUEIMALIÑOS claudia Patricia
congresos y reuniones científicas
Experimental analysis of the effects of climatic variables on microbial communities of a temporary pond (Patagonia, Argentina).
GEREA, M., SOTO CARDENAS, C., REISSIG, M., UNREIN, F. Y QUEIMALIÑOS, C.P.
Congreso; IV Southern Connection Congress; 2010
Temporary ponds are especially sensitive to climatic changes. The gradual increase in mean annual temperature and the variations in rainfall affect water levels and, in consequence, influence on the natural eutrophication processes. In order to analyze the synergic effect of these variables on microbial community dynamics, we simulated two possible climatic scenarios with variations in water levels and nutrient concentrations through the addition of aquatic avian feces. We performed experiments in mesocosms with a 2 x 2 factorial design, where water level (Deep and Shallow) and feces addition (With and Without Feces) represented the principal factors. An equal mass of sediments were added to all mesocosms to allow the colonization of resistance forms. We analyzed nutrient and microbial community dynamics during 10 weeks. A noticeable gradient in nutrient concentration was observed between the four treatments. The development of bacterial community showed a correspondence with phosphorus variations. Bacterivorous nanoflagellates and ciliates presented differential dynamics in the four treatments, with an important prevalence of mixotrophic algae in the Deep one. Meanwhile, heterotrophic nanoflagellates better developed in the treatments With Feces. These results indicate a synergic effect of the forcing variables, with more complex links between competition and predation processes in the enriched treatments.