Abstract

RAMIREZ-RESTREPO, JOHN J.; MENESES-S., VERÓNICA  and  VERGARA-C., ALEJANDRA. ESTUDIO AUTECOLÓGICO DE SCHROEDERIA SETIGERA EN EL EMBALSE TROPICAL RIOGRANDE II, ANTIOQUIA, COLOMBIA. Caldasia [online]. 2015, vol.37, n.2, pp.359-379. ISSN 0366-5232.  https://doi.org/10.15446/caldasia.v37n2.53558.

The aim of this study is to understand the dynamics of Schroederia setigera in the spatial and temporal scales, to determine what the causes of its population dynamics, and to locate this organism in the system Reynolds' associations system and in the Morph-Functional-Groups. The investigation was conducted in Riogrande II reservoir (6° 35' 57''- 6° 28' 79'' N, 75° 32' 17'' W) whose retention time was 72, 8 days. In it were sampled five stations at fortnightly intervals during one year (July 2002 to July 2003) in which data from three climate variables, five physical and 15 chemicals ones were obtained. For this species, its mean growth rate and renovation, mean time of generation, growing type and spatial and temporal arrangement, were calculated. A redundancy analysis (RDA) was used to establish the relation between the biological and environmental variables. Along the time, the algae adjusted to a pattern of three 'peaks' occurred in the season of the lowest rainfall when the nutrients were indeed concentrated, and the light climate was affected. In the five stations the species was grouped and in the space its disposition was at random. The first four axis of the RDA included NO₃^-, SiO₂, pH, SS y %SO₂, attenuation vertical light coefficient, chlorophyll a, and different competitors. This species is a C-strategist and, as other Chlorococcales, it is a typical taxon of eutrophic systems, with high growth and change rates, short regeneration time, and contagious distribution pattern in temporal scale, therefore, under a non-equilibrium ecology, more density in the seasons of low rainfall when nutrients were concentrated and light climate was affected. In the space, the species showed a random distribution because of the current regimen of this basin. Besides, it is not limited by resources, it responses with an adaptation to the optimal climate of water system with its circular section, and acicular shape attenuated to both ends that places it as a good light-harvester; thus, it can be included in the J or X1 associations and in the Morph- Functional-Group IV.

Keywords : Chlorococcal algae; Schroederia setigera; autecology; tropical reservoir; Colombia.

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