In the COMPACT version of the PHYTO-PAM-II all components including the measuring chamber are contained in a single compact housing. Hence, except for the USB-cable for communication with the PC, normal operation does not involve connection of external cables, so that this device is particularly suited for on-deck and field applications. It features five wavelengths of fluorescence excitation and actinic illumination (440, 480, 540, 590 and 625 nm). In addition, also white light for actinic illumination and far-red light for preferential excitation of photosystem I is provided.

Due to its innovative optoelectronical design with 60 LED power-chips on 10 x 10 mm active COB-area (metal core Chip-on-Board) the PHYTO-PAM-II provides determination of the wavelength-dependent light-saturation characteristics but also determination of the wavelength-dependent absorption cross-section of photosystem II, σII(λ), can be measured. σII(λ) varies considerably between different types of phytoplankton and knowledge of σII(λ) is essential for estimation of electron transport rates from fluorescence parameters.


The COMPACT version of the PHYTO-PAM-II features a 15 mm (outer Φ) round cuvette, which is illuminated from the bottom, with fluorescence being detected at right angle. In this way, the whole sample is illuminated homogeneously and a representative part of the sample is monitored.

Reference spectra measured with dilute suspensions of pure cultures, corresponding to 5-point fluorescence excitation spectra, serve for automated online deconvolution of up to 4 different pigment types of phytoplankton (green algae, diatoms/dinoflagellates, cyanobacteria and phycoerythrin containing organisms, like cryptophytes).