The WATER-PAM is the PAM fluorometer of choice when very low chlorophyll contents of samples require outstandingly sensitive fluorescence detection. The three different types of the WATER-PAM are designed to analyze suspension samples, surfaces, or a continuous water flow, respectively.

The parameters measures are chlorophyll content and photosynthetic activity. All WATER-PAM chlorophyll fluorometers can be operated in the stand-alone mode which facilitates measurements in the field.

The WATER-PAM chlorophyll fluorometers achieve outstanding sensitivity by fluorescence detection with a particularly red-sensitive photomultiplier combined with special preamplifier electronics. In this way, detection limits for suspensions down to 0.1 µg chlorophyll/liter are achieved.

Damage to the susceptible photomultiplier tube by external radiation is averted by an automatic switch-off circuit. Consequently, the photomultiplier tube is shielded from external light during measurements.


PAM-CONTROL unit with data lines from WATER-PAM emitter-detector unit.

A further feature of WATER-PAM chlorophyll fluorometers is that they can be operated independently from line connection and computer by the battery-powered PAM-CONTROL unit.

The same PAM-CONTROL unit functions as a physical interface between measuring unit and computer for operation of the WATER-PAM by the WinControl software.
 

The emitter-detector unit, of the CUVETTE version features a cylindrical holder for a 15 mm diameter quartz glass cuvette (WATER-K). The cuvette is surrounded by light-emitting diodes (LED) delivering PAM measuring light and actinic illumination to the sample.

Detection of fluorescence at wavelengths longer than 710 nm occurs at the bottom of the cuvette. Best results are achieved using sample volumes between 2 and 3 ml.


WATER-ED, the emitter-detector unit of WATER-PAM CUVETTE version with round fluorescence cuvette and cover of measuring chamber (black cylinder).

The emitter detector unit is available with two different LED colors. The blue LED version (WATER-ED/B) exhibits lowest stray light interference. This WATER-ED/B has additional far-red LEDs light source for fast PS I-driven opening of PS II reaction centers required for evaluations of Fo’ fluorescence levels.

The red LED version (WATER-ED) is frequently used to analyze cyanobacteria which tend to absorb inefficiently in the blue: this version is available with far-red or blue photosystem I light.
 

The FIBER version probes surfaces of solid objects by using an optical fiber. Typically the FIBER version is employed to examine photosynthetic layers on various submerged surfaces (periphyton, microphytobenthos) and soil crusts but also to screen samples on microwell plates.

The FIBER version is less sensitive than the CUVETTE and FLOW THROUGH version so that for toxicity biotest systems a chlorophyll concentrations around 100 - 500 µg chlorophyll/liter is recommended.


WATER-EDF, the emitter-detector unit of WATER-PAM FIBER version mounted on stand ST-101.

As in the case of the CUVETTE version, the emitter-detector unit of the FIBER version can be equipped with different-colored LEDs: the WATER-EDF1.5R uses red measuring and actinic light but these light sources are replaced by blue LEDs in the WATER-EDF1.5B.
WATER-EDF, the emitter-detector unit of WATER-PAM FIBER version

The WATER-EDF1.5R is configured with an additional blue light source to selectively excite the photosystem I in cyanobacteria or, alternatively, with a far-red light source for photosystem I excitation in many other photosynthetic organisms.


Probing photosynthesis of a soil crust using the FIBER version of the WATER-PAM


WATER-EDF, the emitter-detector unit of WATER-PAM FIBER version examining traces of photosynthetic cells.


WATER-EDF, the emitter-detector unit of WATER-PAM FIBER version mounted on stand ST-101.
 

The FLOW THROUGH version of the WATER-PAM has a water-proof emitter-detector unit exhibiting a transparent window through which measuring and actinic light is emitted.

 

Fluorescence detection occurs through another transparent window at right angles with the window for light emission. The optical windows are positioned within a black cylinder with inlet and outlet connections.
WATER-FT, the emitter-detector unit of FLOW THROUGH version of the WATER-PAM mounted on metal stand. The front face shows the two metal ports for water flow and another port for the spherical PAR sensor, US-SQS/WB.

 

The two connections permit continuous fluorescence monitoring when a commercial water pump is connected to the outlet and a sampling hose placed in the reservoir to be examined.

Because of its capacity for continuous analysis, the major applications of FLOW THROUGH version are in the field of limnology, oceanography, water management and drinking water monitoring.


Measuring chamber of WATER-FT emitter-detector unit.

 

The FLOW THROUGH version is equipped with either red (WATER-FT/R) or blue LEDs (WATER-FT). The former configuration is suited for detection of cyanobacteria with weak absorption in the blue, the latter one exhibits particularly low background signals and can be used when green algae or diatoms are to be analyzed.

Additional light sources for specific excitation of photosystem I are omitted because of too short residence times of samples in front of the emission detection window.

The PAM-CONTROL unit can conduct independently PAM fluorescence measurements but it can also act as physical interface between fluorometer and computer using WinControl-3 software.

The PAM-CONTROL unit is specialized to operate various extremely sensitive setups for chlorophyll fluorescence measurements: the MICROSCOPY-PAM, the MICROFIBER-PAM and the WATER-PAM.


Universal control unit for ultrasensitive chlorophyll fluorescence measurements in a variety of specialized optical geometries


Schematic representation of Universal Control Unit PAM-CONTROL

 

Common to these three setups is the use of the same light-emitting-diodes (LED) as sources of measuring and actinic light, as well as for saturation pulses. Also, all setups use ultrasensitive photomultipliers: as a consequence, they are not suited for operation in the presence of non-modulated background light which would interfere with chlorophyll yield determinations.

The capacity of data storage comprises 4000 data sets. An extensive menu provides full control of instrumental settings and a variety of measuring protocols.

 

CUVETTE Version

Stirring Device WATER-S

To prevent settling of particles, a battery-driven stirring motor can be mounted on top of the emitter-detector box of CUVETTE version. Stirring of suspensions occurs by replaceable flattened rod consisting of Perspex.

Spherical Micro Quantum Sensor

US-SQS/WB

The submersible sensor serves for PAR measurements under actual experimental conditions and for calibrations of internal actinic light lists. A sensor holder is supplied for mounting the sensor on the emitter-detector box. PAR data are acquired by the PAM-CONTROL unit. For detailed sensor information see US-SQS/L.

 

FIBER Version

Mini Quantum Sensor US-MQS/WB

The cosine-corrected US-MQS/WB serves for PAR measurement at sample level and for calibration of the internal actinic light list. PAR data are collected by the PAM-CONTROL unit. For detailed information on sensor properties see MQS-B.

 

FLOW THROUGH Version

Spherical Micro Quantum Sensor
US-SQS/WB

Submersible PAR sensor for calibration of the internal actinic light list. The sensor can be inserted through a special port of the optical compartment of the FLOW THROUGH unit. For measurements, the data line of the sensor is connected to the PAM-CONTROL unit. For detailed sensor information see US-SQS/L.

 

Benchtop Adapter WATER-FT/SK

The FLOW THROUGH version of the WATER-PAM can be converted in a benchtop fluorometer using the WATER-FT/SK accessory. The emitter-detector unit of the FLOW THROUGH version can be fixed in upright orientation using the base cylinder of the WATER-FT/SK accessory. The top cylinder of the WATER-FT/SK encircles the measuring chamber containing the emission and detection windows. The measuring chamber is closed by a special cover. A holder mounted above the emission window of the emitter-detector unit permits easy positioning of a round fluorescence cuvette (WATER-K).