Fluorometer | Flanders Marine Institute

Flanders Marine Institute

Platform for marine research


A fluorometer measures the intensity of fluorescence characteristic for certain substances. Fluorescence is the phenomena of some compounds to absorb specific wavelengths of light and almost instantaneously emit longer wavelengths of light. On board of the RV Simon Stevin, VLIZ has installed two fluorometers. One fluorometer is deployed in the drylab and executes measurements of chlorophyll a. The other, located in the bow thruster room, measures besides chlorophyll a also turbidity. Chlorophyll a fluorescence is one of the simplest ways to determine the concentrations of phytoplankton in water.

How does a fluorometer work?

Fluorescence is the phenomenon of some compounds to absorb specific wavelength of light and almost instantaneously emit longer wavelengths of light. Chlorophyll a naturally absorbs blue light and emits, or fluoresces, red light. A fluorometer transmits an excitation beam of light in the blue range and detects the fluorescent red light emitted by the chlorophyll. In general, the intensity of fluorescence is directly proportional to the concentration of chlorophyll a.

Note! The fluorometers, which VLIZ puts at the disposal, measure the relative values of chlorophyll a. To investigate the absolute values, a calibration of the water is needed.


Usefulness of the fluorometer?

  • Simplest method to monitor phytoplankton

Some studies:

  • Spatial variation in phytoplankton dynamics in the Belgian coastal zone of the North sea studied by microscopy, HPLC-CHEMTAX and underway fluorescence recordings:

Muylaert, K. et al. (2006)

The VLIZ fluorometer is also used in the LifeWatch project and the JERICO-next project.

Technical details

Fluorometer in the drylab:

  • Chlorofyl a:
    • 470EX/695EM
    • Sensitivity: 0,02 µg/l
    • Range: 0-125 µg/l

The fluorometer installed in the bow propeller room combines measurements of chlorophyll a and turbidity:  

  • Turbidity:
    • Wavelength: 700 nm
    • Sensitivity: 0,013 NTU
    • Range, typical: 0-25 NTU
  • Fluorescence:
    • Sensitivity: 0,025 µg/l Chl
    • Range, typical: 0-50 µg/l Chl
    • Wavelength: ex/em 470/695 nm

How to use a fluorometer?

For more information about our rental service, please contact VLIZ

Use and conditions

Note: if you use a fluorometer of VLIZ as a scientist, please refer to it in your publications as: 'This work was supported by data & infrastructure provided by the Flanders Marine Institute (VLIZ)'.