Abstract

VILLABONA-GONZALEZ, Silvia L; BUITRAGO-AMARILES, Robinson F; RAMIREZ-RESTREPO, John J  and  PALACIO-BAENA, Jaime A. Rotifer biomass of two reservoirs with different trophic states (Antioquia, Colombia) and its relationship with some limnological variables. Actu Biol [online]. 2014, vol.36, n.101, pp.149-162. ISSN 0304-3584.

Rotifers biomass was evaluated across longitudinal and vertical axes of the photic zone in the La Fe y Riogrande II reservoirs (Antioquia), Colombia, with different trophic states during periods of high and low precipitation. IN addition, its relationship with temperature, dissolved oxygen, pH, transparency, nutrient availability, and phytoplankton biomass was analyzed. In both reservoirs, rotifer biomass was dominated by Asplanchna girodi De Geurne, 1888, and it was significantly higher in the reservoir with a lower trophic state. Even though rotifers biomass did not exhibit a longitudinal gradient, a vertical zonation in the photic zone was documented, with the greatest biomass at 10% and 1% of light intensity. Patterns of variation in total rotifer biomass and in dominant species biomass appear to be determined primarily by the entry of suspended solids into the reservoir with the higher trophic state, and by phytoplankton biomass and density in the reservoir with lower nutrient levels. Contrary to expectations, rotifer biomass was not favored by increasing trophic state. The most important factor determining rotifer biomass was the quality of food resources in each reservoir.

Keywords : Asplanchna girodi; biomass; phytoplankton; reservoirs; rotifers; suspended solids.

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