The predecessor of the DIVING-PAM-II (the DIVING-PAM) has been proven as reliable and robust chlorophyll fluorometer for studying photosynthesis in and under water. To date, about 500 scientific papers containing measurements with the DIVING-PAM have been published.

The DIVING-PAM-II continues the proven and trusted design of its predecessor but advances data acquisition and instrument control by employing the latest progress in LED technology, optics and electronics.

DIVING-PAM-II and Universal Sample Holder DIVING-II-USH

The DIVING-PAM-II fluorometer permits examinations of photosynthesis down to 50 m water depth. All functions of the instrument can be controlled by 10 infrared reflection switches situated inside a transparent, cylinder-shaped housing. A new feature is the energy-saving B/W screen which displays instrument status and measured data. The transflective screen is readable even under sunlight. For long-term assessment of photosynthesis, the instrument can also be operated by a computer via a special underwater cable.

The innovative Miniature Spectrometer MINI-SPEC, being part of the basic DIVING-PAM-II system, adds a new level of information to studies of photosynthesis. The MINI-SPEC measures spectra of PAR, which are known to vary significantly with water depth. The device also permits spectral analyses of reflectance and fluorescence emission of a sample. Also new is an internal PAR sensor which continuously records the intensity of the internal light source of the DIVING-PAM-II.

In situ investigations of cyanobacterial photosynthesis using a Walz DIVING-PAM fluorometer has been released. The video was recorded during a research campaign in Greenland (2013) which was targeted to photosynthesis of algae on surfaces of submarine mineral formations (ikaide columns). This research campaign was sponsored in part by Walz.


Miniature spectrometer for PAR measurement, spectral information on PAR and reflectance

Wireless LAN for convenient data download at experimental site

Graphical and alphanumerical display by low-power consuming transflective B/W screen

High power LED for actinic light and saturation pulses. Far red LED for PS I excitation.

Advanced pressure and temperature sensor

High capacity battery for more than 1,300 PS II yield measurements. Flash memory for more than 27,000 saturation pulse analyses

Continuous monitoring of internal light intensity by built-in PAR sensor

Automatic calculation of all relevant parameters of saturation pulse analysis

Accessories included in the basic system:
1.5 m flexible fiber optics, miniature spectrometer, distance clip, dark leaf clips, surface holder, PC Interface Box, battery charger, USB cable, 5 m underwater cable, WinControl-3 software packed in a rugged outdoor transport case


The color of light emitted by the primary LED distinguishes the BLUE from the RED version of the DIVING-PAM-II fluorometer (Fig. 1). The BLUE version (DIVING-PAM-II/B) possesses a blue LED emitting maximally around 475 nm which is replaced by a red LED emitting maximally around 655 nm in the RED version (DIVING-PAM-II/R). Both versions have a second LED providing far red light for specific excitation of photosystem I.

The second difference between the two versions is the spectral window for fluorescence detection. The BLUE version detects fluorescence at wavelengths > 630 nm but the RED version detects fluorescence at wavelengths > 700 nm (Fig. 2).

Figure 1: Typical LED emission spectra normalized to their maxima. The blue curve corresponds to the spectrum of the blue LED of the DIVING-PAM-II/B, the orange curve represents the red LED in the DIVING-PAM-II/R. Both DIVING-PAM-II versions possess a far red LED which emits maximally above 700 nm (rightmost curve). Max, peak wavelength in nm. FWHM, full width at half maximum in nm.


Universal Sample Holder DIVING-II-USH

The DIVING-II-USH sample holder is designed for the specific requirements of underwater investigations of samples like sea grass, macroalgae, and corals. The sample holder permits single-hand operation of the DIVING-PAM-II by triggering measurements via a release button integrated in the handhold. A special mount positions the Miniature Spectrometer MINI-SPEC parallel to the sample level. The robust trigger and spectrometer cables as well as the fiberoptics are bundled by a nylon-mesh-cover so that harmful bending of the fiberoptics can be largely avoided.


Adapters for DIVING-II-USH

The broad range of applications of the DIVING-II-USH sample holder includes measurements using ambient light or light derived from the internal DIVING-PAM-II light source.
Further, the underwater clips for dark-acclimation (DIVING-MLC and DIVING-LC) can be readily connected to the fiber optics alone or held by the DIVING-II-USH holder.


Surface Holder DIVING-SH

The DIVING-SH accessory has a central port to accommodate the DIVING-PAM-II fiberoptics. For long-term measurements of bulky objects, the DIVING-SH can be attached to the sample by three rubber bands equipped with end hooks.


Underwater Cables DIVING-K25/-K50

For remote-control of the DIVING-PAM-II, reliably performing underwater cables either 25 m (DIVING-II/K25) or 50 m (DIVING-II/K50) long are available. The 50 m cable is supplied with the charger DIVING-II/L15 which delivers an increased voltage to efficiently charge the DIVING-PAM-II in the presence of the elevated resistance of the DIVING-II/K50.


Magnet Sample Holder DIVING-MLC

Clip for dark-acclimation of flat samples consisting of two magnetic parts. One part has a fiberoptics port which is closed by a flexible black rubber cap with a central slit. For measurements of dark-acclimated samples, the fiberoptics is pushed through the cap’s slit so that natural light does not arrive at the sample and the dark-acclimated state is maintained.