| PumpProbe |
PumpProbe Fluorometer is a submersible double-flash pulse fluorometer for continuos measurement of chlorophyll fluorescence parameters in situ and for determination on this chlorophyll concentration and fundamental photosynthesis properties of phytoplankton in the sea.
The double flash fluorometer basically contains two excitation channels and one emission channel provides a weak, probe flash which is used for measuring the fluorescence yield of Photosystem II. Another excitation channel provides a pump flash, which is used for closing the reaction centers of PS II. Both excitation signals are provided by xenon flashlamps. The light from the flashlamps is collected by condensers and by a set of bluegreen excitation filters. The emission signal is collected by the emission condenser and filtered by a red filter before striking the photodetector.
The controller is based on a single board, PC/DOS - compatible computer. It executes programmed experimental protocol, and performs data acquisition and analysis.
The instrument is typically programmed to generate a sequence of probe-pump-probe flashes, where flash intensity and timing can be varied as required by the experimental protocol. The fluorescence signal recorded during the first probe flash is a measure of the constant part of the fluorescence yield. The fluorescence signal measured during the second probe flash is a measure of PSII fluorescence yield that results from closing the traps by the pump flash. If the pump flash has a saturating intensity, and the second probe flash is applied 50-70 microseconds following the pump flash, then the fluorescence signal measured during the second probe flash is a measure of PSII fluorescence yield with all the traps closed. Depending on the experimental protocol, the different photosynthetic parameters can be measured.
Description on the ground of: P.G. Falkowski, Z. Kolber, Measurements of Variable Fluorescence in the Sea with a Pump and Probe Fluorometer
The fluorometer used in our Institute was made in the firm EcoMonitor, Moscow.
Measured parameters:
fluorescence
temperature
underwater PAR irradiation
depth.
Measurement ranges: | |
| Chlorophyll a concentration (based on fluorescence) | 0.03 - 50 mg m-3 |
| Underwater irradiance (PAR range) | 0.03 - 300 W m-2 |
| Temperature | 0 - 30 C |
| Depth | 0 - 200 m |
| Fluorometer: | |
| Excitation wavelength range | 400 - 550 nm |
| Registration wavelength range | > 680 nm |
| Energy of "probe flash" | 0.01 J |
| Energy of "pump flash" | 0.01 - 1 J |
| Duration of "probe flash" | 0.01 ms |
| Duration of "pump flash" | 0.01 ms |
| Interval between "pump and probe" flashes | 0.05 - 1 ms |
| On-board block size | 300 x 300 x 50 mm |
| On-board block weight | 0.5 kg |
| Submerge unit size | sphere, d = 250 mm |
| Submerge unit weight | 10 kg |
| Voltage | 220 V or 12 V |
| Required power | 25 W |