Multiple Excitation Wavelength Phytoplankton & Photosynthesis Analyzer

PHYTO-PAM instruments facilitate measurements of mixed algae populations for analysis of chlorophyll content and photosynthetic performance of variously pigmented phytoplankton.
Deconvolution of the fluorescence responses of these phytoplankton groups is based on differences upon excitation with multiple excitation wavelengths. In contrast to the MULTI-COLOR-PAM fluorometer, where one of five colors can be applied at the time, with PHYTO-PAM devices different excitation wavelengths are applied quasi-simultaneously in form of µsec measuring light pulses with rapidly alternating colors.

PHYTO-PAM-II MODULAR Version with connected Miniature Magnetic Stirrer US-SQS/WB.
Multi-Wavelength Analysis for the simultaneous assessment of photosynthetic performance of mixed phytoplankton samples.


Miniature photomultiplier detectors enable extremely sensitive fluorescence detection down to a concentration of 0.1 µg Chl/l as it can be found in natural surface waters or coastal seawater for standard PAM measurements like saturation pulse quenching analysis, determination of effective PS II quantum yield, light response curves and induction curves. The PHYTO-PAM-II additionally features a fast kinetics mode for assessment of the wavelength-dependent absorption cross section of PS II, σII(λ), from evaluation of the O-I1 kinetics and consequent estimation of wavelength-dependent absolute electron transport rates, ETRII(λ).

PHYTO-PAM-II COMPACT version for the simultaneous assessment of photosynthetic performance of up to four differently pigmented algae groups in natural surface water


PHYTO-EDF with special 9-armed fiberoptics for laboratory or field use


PHYTO-PAM-II chlorophyll fluorometers feature five measuring light wavelengths (440, 480, 540, 590 and 625 nm) for simultaneous excitation of four pigment groups of phytoplankton. The same five colors plus white are provided for actinic illumination and determination of wavelength-dependent absorption cross-section and wavelength-dependent electron transport rate. 

Two versions presently are available:

 COMPACT version: The complete measuring system contained in a single compact housing. Including Spherical Micro Quantum Sensor US-SQS/WB, which is prerequisite for calibration of the multi-color photosynthetically active radiation (PAR) and reliable quantification of electron transport parameters from fluorescence measurements.

Accessory: Stirring Device WATER-S.

  MODULAR version: Emitter- and detector-units mounted on a separate optical unit with the possibility of exchanging detector filters.

Requires Spherical Micro Quantum Sensor US-SQS/WB.

Accessories : Miniature Magnetic Stirrer PHYTO-MS and the Temperature Control Unit US-T


A FIBER version of the PHYTO-PAM is available with four wavelengths of excitation (470, 520, 645 and 665 nm) and one actinic light source (655 nm)

 FIBER version Control unit and compact emitter-detector box with a special fiberoptics forming the link to the sample. For periphyton and microphytobenthos measurements.

A cosine corrected Mini Quantum Sensor US-MQS is available to measure photosynthetically active radiation (PAR) at the fiberoptics exit to calibrate the light list of the PHYTO-PAM


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.

PHYTO-PAM-II COMPACT version for the simultaneous assessment of photosynthetic performance of up to four differently pigmented algae groups in natural surface water


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.

Multiple Excitation Wavelength Phytoplankton & Photosynthesis Analyzer


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.

PHYTO-PAM-II/ED compact design featuring one single instrument


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).



The Emitter Detector Fiberoptics Unit PHYTO-EDF is connected to the standard Power-and-Control-Unit PHYTO-C of the PHYTO-PAM Phytoplankton Analyzer. All electro-optical components are contained in a single compact housing, with special fiberoptics (9-armed) forming the optical link to the sample. The fiberoptics can be mounted on a stand with base plate.

PHYTO-EDF with special 9-armed fiberoptics for laboratory or field use

The compact emitter-detector box houses 4 different LED measuring light sources (470 nm, 520 nm, 645 nm and 665 nm), the actinic LED light sources (655 nm) and a photomultiplier detector. All LED light sources are equipped with miniature fiber couplers and short-pass filters (λ < 695 nm). The detector is protected by a special long-pass filter set (λ > 710 nm) which is optimized for low background signal.

The FIBER version is well-suited for highly sensitive assessment of photosynthetic activity on surfaces, as e.g. periphyton, microphytobenthos and microbial mats. Due to the use of a photomultiplier, large signals are obtained even at low sample densities. On the other hand, at high gain the photomultiplier has to be protected from ambient light. For this purpose, as well as for dark-acclimation of the sample, a darkening-box is provided which covers the sample and encloses the fiberoptics endpiece.

The latter consists of a 4 mm Ø perspex rod, the front of which is in contact with the sample surface via a thin layer of water. The perspex rod serves the purpose of mixing the different types of light and to guide the fluorescence to the detector fiber (1.5 mm Ø, in center of fiber bundle). While measurements are possible with the perspex rod being submerged in algae suspensions, the sensitivity is distinctly lower than PHYTO-PAM-II instruments. For toxicological work, a 4 mm Ø quartz glass rod (EDF-Q) is available.

The four wavelength PHYTO-PAM Fiber version excites chlorophyll fluorescence by microsecond LED-light pulses alternating between four different wavelengths measuring light. The photosynthetic activity is assessed using red actinic light and saturation pulses.

The four colored measuring lights are absorbed to different extents by the green algae, diatoms / dinoflagellates and cyanobacteria leading to characteristic differences in the fluorescence responses of these three types of phytoplankton.

After system calibration with the separate phytoplankton groups, the relative contents of these groups can be determined in unknown samples by computer-aided deconvolution using the PhytoWin software. The photosynthetic properties of these groups are characterized by their effective PSII quantum yields, relative electron transport rates (ETR) and light response curves.

Special 9-armed fiber optics for the PHYTO-EDF emitter-detector unit with optional light mixing rod shown in the middle

PHYTO-PAM-II Operation Software
General Features and Graphical User Interface

PhytoWin-3 Software operates PHYTO-PAM-II instruments in conjunction with a Windows PC.

PhytoWin-3 software features nine different windows for analysis and display of measured and calculated data as well as script file operation for automation of experimental protocolls.

Slow Kinetics recording of online deconvoluted responses of the four pigment groups. Consecutive addition of 2x5µl Phaeodactylum, 10 µl Chlorella, 2.5 µl Synechococcus and 2x10µl Cryptomonas to cuvette filled with growth medium.

Reference Spectra are readily measured with single species cultures. Being independent of variations between individual instruments they are universally valid and can be exchanged between users.

Script files allow to program the time sequence of all commands that can be carried out manually. In this way, complex measuring routines can be automated.


Channels: Original, unbiased fluorescence information at 5 different excitation wavelengths

Settings: Controls for instrument settings, like measuring pulse frequency, actinic intensity, saturation pulse width and intensity, clock interval, number of averages, etc.

Algae: Deconvoluted fluorescence information for cyanobacteria, green algae, diatoms/dinoflagellates and phycoerythrin-containing organisms (e.g. cryptophytes) based on previously recorded reference excitation spectra; user surface for Chl determination

Light Curve: Graphic display of light response curves; effective quantum yield and relative electron transport rate (ETR) as a function of PAR, Curve fitting on the basis of a modified Eilers & Peeters model (1988) or Platt (1980)

Slow Kinetics: Graphic display of slow kinetics recorded in the SP-Analysis mode

Report: File in which all measured data and instrument settings are stored, can be edited by the user and exported into other programs

Reference: Recording and display of reference excitation spectra of cyanobacteria, green algae, diatoms/dinoflagellates and phycoerythrin-containing organisms

Fluo Spec: Display of measuring light characteristics and non-normalized reference excitation spectra

Fast Kinetics: Control and graphical display of fast kinetics analysis providing information on the wavelength-dependent absorption cross-section of PS II, σII(λ)

Free software updates will keep your instrument always up-to date on latest developments.
PhytoWin-3 cannot be used for operation of first generation PHYTO-PAM instruments.


Operation Software for the four wavelength PHYTO-PAM
General Features and Graphical User Interface

Instruments of the four wavelength PHYTO-PAM version are operated by PhytoWin Software in conjuction with a Windows PC. Four wavelength PHYTO-PAM versions can not be operated by PhytoWin-3.

The PhytoWin software features seven different tabs (Channels, Algae, Report, Light Curve, Settings, Reference, Delta F) for the analysis and display of measured and calculated data.

Light curve tab: Light curves give information on the light adaption state and the photosynthetic capacity of a sample. With increasing quantum flux density the effective quantum yield of PSII decreases, as PSII reaction centers progressively close and an increasing amount of energy is dissipating as heat.

The derived fit curves are calculated on the basis of a modified Eilers & Peeters model (1988) or Platt (1980).

Channels tab: Original and unbiased fluorescence information from the four different excitation wavelengths (470, 520, 645 and 665 nm).

The current signals of the four different excitation channels are displayed in the Ft line and additionally in four indicator bars. Besides the individual Ft-signals, also the mean (average of the four signals) is depicted

Algae tab: In the algae tab the deconvoluted fluorescence information for green algae cyanobacteria and diatoms is shown. The data are based on previously recorded reference excitation spectra.

In analogy to the channels window, the deconvoluted fluorescence parameters Ft, F, Fm, dF and Yield are displayed for the different algae groups detected in the sample. In addition also the fitted chlorophyll concentrations of the three types of phytoplankton are shown.

Report tab: The Report is organized in terms of separate “records” each of which contains a number of measurements, normally defined by application of a saturation pulse.

Other types of measurements are documented in the report as well, are Chl determination and the determination of a new reference spectrum.



Stirring Device WATER-S

Miniature stirring device (battery powered) that can be mounted on top of the PHYTO-PAM-II COMPACT version. It is equipped with disposable perspex stirring paddles. A potentiometer allows the adjustment of the stirring rate. The part is shipped with a set of ten Stirring Paddles WATER-R.


Stirring Paddles WATER-R

Spare stirring paddles (10 pieces) for the Miniature Stirring Device WATER-S. Already included in the WATER-S scope of delivery.


Quartz Glass Cuvette WATER-K

15 mm diameter round quartz glass cuvette for the PHYTO-PAM-II COMPACT version. (Two cuvettes are part of the purchased parts package of PHYTO-PAM-II COMPACT version.)


Miniature Magnetic Stirrer

Based on rotating magnetic field; connecting to Power-and-Control Unit PHYTO-II-C; with special adapter plug to be mounted in bottom port of Optical Unit ED-101US/MP controlled by the Power-and-Control Unit PHYTO-II-C.


Temperature Control Unit US-T

The US-T unit consists of a heat-transfer head with a cooling/heating Peltier element, and a separate power-and-control unit. The heat-transfer head is mounted on top of a Walz optical unit (ED-101US-type) so that the dip of the rod is in touch with the suspension investigated. The achievable temperature spread in suspensions is about 30 K; absolute temperatures depend on ambient temperature.

Download the manual for detailed information.


Quartz Glass Cuvette US-K1/US-K0

The standard 10 x 10 mm cuvette US-K1 is already provided in the Optical Unit ED-101US/MP of the MODULAR version. For very difficult samples it might be beneficial to use the US-K1 cuvette with one side mirrored.


Quartz Glass Mixing Rod EDF-Q

Quartz glass mixing rod (4 x 50 mm) substitutes for the standard Perspex Mixing Rod EDF-P. Suited e.g. for toxicological investigations.


Perspex Mixing Rod EDF-P

Set of three perspex mixing rods (4 x 50 mm). Already included in the PHYTO-EDF scope of delivery.


Mini Quantum Sensor US-MQS/B

Consisting of the cosine corrected Mini Quantum Sensor US-MQS/B together with the Adapter Set MQS-B/A for the calibration of the internal light list of the PYHTO-PAM FIBER version and WATER-PAM FIBER version.