ABSTRACT

Abstract The chlorophyll a specific light attenuation coefficient kc, (in m2mg−1 chl a), is an apparent optical property of the underwater light field, resulting from the interaction between sun-light and the phytoplankton suspended in natural waters. The determination of kc is carried out under the natural light conditions of a water body, whereas the specific light absorption coefficient of chlorophyll a, (in m2mg−1 chl a), is an inherent optical property of the phytoplankton. That parameter, , is determined using a laboratory spectrophotometer. Both kc and are necessary to calculate the quantum requirement of phytoplankton photosynthesis from a, the linear part of the photosynthesis versus irradiation curve. The spectral distribution of kc(φ ) and (φ ) contains information about the species composition of the phytoplankton community.