Comparison of methods for measuring light absroption by algae and their application to the estimation of the package effect
J. Mercado, C. Jiménez, F.X. Niell and F.L. Figueroa

In the present work three different methods of estimation of light absorption used for the calculation of light absorption efficiency by algae are compared. The use of absorption meters for the estimation of total absorption of a microalgal culture is proposed. It has been found that flat sensors (2π sensors) over estimate light attenuation and a combined use of sensors with different acceptance angles (4π sensors) is proposed. On the other hand, total absorption (TA) of the thalli of Porphyra leucosticta and Ulva rigida estimated by integrating sphere is correlated with the absorptance peaks of the main pigments. The linear equations TA = -0.046+0.894A678 and TA = -0.057+0.735A678 for P. leucosticta and U. rigida respectively, are proposed to estimate the total absorption of the thalli from chlorophyll a absorption peak(678 nm). An over estimation of absorptance by opal glass is obtained. Spectrally averaged in vivo absorption cross section, normalized to chlorophyll a(so-called a* values) decreased when pigment content increased, which isdue to an increase of the packaging of the pigments, leading to a decrease of the efficiency of light absorption.

Keywords: Light absorption, package effect, macroalgae, Dunaliella.
Contents of this volume Sci. Mar. 60(Suppl.1) : 39-45 Back PDF
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