INSTITUTO DE LIMNOLOGIA "DR. RAUL A. RINGUELET"
Unidad Ejecutora - UE
A quick and effective estimation of algal density by turbidimetry developed with Chlorella vulgaris cultures
FERRANDO, N.; BENÍTEZ, H. H.; GABELLONE, N. A.; CLAPS, M. C.; ALTAMIRANO, P. R.
ASOC ESPAN LIMNOL-MISLATA
Lugar: Barcelona; Año: 2015 vol. 34 p. 397 - 397
The use of Chlorella vulgaris Beijerinck as food for zooplankton implies the need to optimize the algal culture to maintain its growth over time. In this paper, a methodology that relates the algal density and culture turbidity was developed to estimate the culture biomass. This technique was improved by applying the digital analysis for algal counting that promotes accuracy, low culture disturbance, easy repetition and rapid obtainment of results. Two cultures of C. vulgaris were obtained in 3 l containers with continuous lighting (eight Light-emitting diodes (LEDs), each of 1100 mCd and 660 nm) and aerators to prevent algae sedimentation. Incubation was continued for two weeks, after which culture 1 reached a turbidity of 214 NTU, and culture 2 of 280 NTU. The sample counting was performed by means of digital images taken in an inverted microscope. Aliquot sedimentation was performed applying direct sedimentation and sedimentation with previous homogenization. In order to compare the fit of both sedimentation methodologies, photographs were taken in the central, intermediate and peripheral sectors of the sedimentation chamber. The data dispersion found using the technique of direct sedimentation determines low reliability of the estimation. Detailed statistical analysis suggested that the sedimentation heterogeneity responds to a settled algal pattern, with increasing density from the periphery to the centre of the sedimentation chamber. The inclusion of a previous homogenization process promotes a better model fitting and determines the increase of the consistency of the technique.