Underwater Fluorometer with Miniature Spectrometer
The DIVING-PAM-II is the successor of the DIVING-PAM which 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 DIVING-PAM have been published.
The DIVING-PAM-II continues the manifold tested design of its predeccessor, but it possesses significant advanced data aquisition and instrument control by employing state-of-the-art optical and electronic components.

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). 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.
  • 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
  • In dry environment, accessories of the MINI-PAM-II fluorometer can be operated in conjunction with the DIVING-PAM-II.

BLUE & RED Version


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.

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 red curve represents the red LED in the DIVING-PAM-II/R. Both DIVING-PAM-II versions can be a far-red LED which emits maximally above 700 nm (rightmost curve). Peak wavelength and full width at half maximum (in brackets) are indicated.

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

Figure 2: Transmittance spectra of detection filters in the DIVING-PAM-II/B (blue line) and DIVING-PAM-II/R (red line).

BLUE or RED Version?

In the case of high chlorophyll contents, a large part of the short wavelength fluorescence, which potentially can be detected by the BLUE version, is reabsorbed by chlorophyll. In such samples the sensitivity of the BLUE version is only slightly better than that of the RED one.
The MINI-PAM-II can be used to investigate cyanobacteria. Cyanobacteria often absorb poorly in the blue., and the studies of cyanobacteria the RED version is normally preferred over the BLUE version which shows low signal to noise ratios with cyanobacteria.
The blue actinic light source of the MINI-PAM-II/B excites the broad short wavelength band of the major light-harvesting complex of photosystem II in higher plants and green algae (LHC II). Red light of the MINI-PAM-II /R excites the comparably minor long-wavelength band of the LHC II. Hence, if LHC II excitation is important, the BLUE version might be superior.
Blue is absorbed by blue light photoreceptors which can stimulate responses like chloroplast relocation in higher plants. Chloroplast relocation can affect the fluorescence signal by changing the efficiency of light absorption. This effect is difficult to distinguish from other fluorescence quenching mechanisms. Choosing the RED version excludes Such blue light effects.



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 A particular mount positions the Miniature Spectrometer MINI-SPEC parallel to the sample level. The robust trigger and spectrometer cables as well as the fiber optics are bundled by a nylon-mesh-cover so thatFyre bending of the fiberoptics can be Basic 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, a singularly rearing cable, 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

One part has a fiber optics 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.