METODOLOGÍA DE RECUENTO DIGITAL DE CHLORELLA VULGARIS, UNA EXPERIENCIA EN LABORATORIO

FERRANDO, NOELIA SOLEDAD; BENITEZ, HERNAN; CLAPS, M. CRISTINA; GABELLONE, NESTOR

Aguas Calientes

Congreso; XVIII REUNIÓN NACIONAL DE LA SOCIEDAD MEXICANA DE PLANCTOLOGÍA, A. C. ; XI INTERNATIONAL MEETING OF THE MEXICAN SOCIETY OF PLANKTOLOGY, A. C.; 2014

Universidad Autónoma de Aguas Calientes

The unicellular alga Chlorella vulgaris common in phytoplankton from pampásic environments in Argentina, is one of the most used experimentally. Among the various proposed methodologies for algal cell counts are automated methods using electronic meters, turbidity measurements that allow to infer the cell number and direct microscope counts in Neubauer chambers. This study presents an alternative methodology for counting using digitized images for determining accurately and quickly the number of individuals in a given volume. This was done in the laboratory with an experiment to observe the effect of grazing from the rotifer Brachionus plicatilis on C.vulgaris under controlled conditions (23 ° C and photoperiod 14/10 h with orbital shaking). The treatments (presence / absence of grazer rotifer) were performed in triplicate and aliquots were removed daily for algal count. The experiment ended after five days. Rotifer density was determined by counting under the microscope. For the algal count digital images were taken under inverted microscope from the aliquotes, previously fixed with Lugol and sedimented in Utermöhl cameras. These images were processed with Image J free software (v 1.47) that allows both count and measurement of each particle in an automated manner. Average grazing varied 6.2 x 104 and 80 x 104. The effect of grazing was evident and statistically significant throughout the experiment. The methodology presented was accurate for assessing the algal density, allowing very low levels of error in the cell count. The population of the rotifer and the presence of eggs increased over time. The method proved to be easy to study grazing by rotifers.