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Estimating the photosynthetic and detrital fractions of seston: A comparison of methods. Working Group 5 Report
Antonio Bode, Félix L. Figueroa, Javier Ruiz

Light absorption by total seston and methanol extractable pigments was studied in samples of coastal waters in the Southern Mediterranean Sea. Several indicators of the relative concentrations of phytoplankton and detritus in the euphotic zone indicated an increase of the detritus fraction with depth. Estimate using total pigments gave a vertical distribution pattern of phytoplankton not directly related to chlorophyll-a. Despite methodological differences, the estimate of detritus based on light absorption analysis and particle and cell size-distribution analysis, were comparable. The ratio between absorbance coefficients at 400 nm before and after methanol extraction was a good estimator of detritus concentrations. No significant differences were found between absorbance ratios computed with a standard spectrophotometer and with an integrating sphere connected to an spectroradiometer, indicating that the pigment absorption technique may be easily implemented in routine field studies.

Keywords: seston, pigment composition, phytoplankton, detritus, light absorption.
Contents of this volume Sci. Mar. 58(1-2) : 59-65 Back PDF
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