Photosynthetic action spectrum: estimation from phytoplankton absorption spectrum

摘要

Abstract: A method is presented for constructing the carbon-based photosynthetic action spectrum which is simple and more economical than conventional methods. The approach uses the shape of the phytoplankton absorption spectrum and the initial slope of the photosynthesis-irradiance curve, determined in board-band illumination. This method assumes that the shape of the absorption spectrum is similar to that of the corresponding action spectrum, when non- photosynthetic pigments are absent, or negligible. The method was tested by constructing action spectra at different stations sampled across the North Atlantic, in five biogeochemical provinces. To assess the performance of the method, the constructed action spectra were compared with the results of measurements made at the same stations. The agreement between the measured and the constructed action spectra was good. Both the measured and constructed action spectra were partitioned into their respective provinces. In each province, a representative spectrum was estimated as the average of all the action spectra measured in the province. Again, the agreement between measured and constructed action spectra was good. It is concluded that the simplified procedure developed here provides an efficient way of estimating the photosynthetic action spectrum for natural phytoplankton populations, and could be used in the computation of primary production at local or large spatial scales. !6