Measurement of Phytobenthos Fluorescence

Unique - an in situ tool for the quick and easy measurement of phytobenthic concentrations

The bbe BenthoTorch is a cost-effective tool which enables real-time measurement of benthic algal concentrations. It can help to improve ecological status assessment (EU WFD criteria) and optimise field sampling by eliminating the need for random sample-taking and testing, and even lengthy microscopic observation.

It is a portable field instrument for the in situ quantification of chlorophyll-a fluorescence on different substrates such as stones and sediment, thus, no sample preparation is necessary. The bbe BenthoTorch can complement sampling by showing the biomass data results on the internal display immediately after measurement. A measurement takes up to only 20 seconds to perform.

Measurement of algal concentrations via fluorescence

The bbe BenthoTorch uses the in vivo fluorescence of algal cells: the cell pigments are excited by LEDs of different colours (wavelngths) and emit red fluorescence light as a natural phenomenon with high sensitivity. The intensity of the chlorophyll fluorescence is used to calculate the different algae as chlorophyll-a, namely green algae, blue-green algae (cyanobacteria) and diatoms.

The calculation is carried out internally using optimised algorithms. The results are shown on the display and stored in the internal memory. An encapsulated USB port enables the data to be transfer to a PC. The PC software is supplied free of charge.

Innovative operating concept - fast measurement

The instrument is robust and completely sealed thus allowing deployment in rough conditions. It is operated through the transparent housing using capacity keys located below the display. The key actions are confirmed by a vibration signal. In this way it is possible to ensure safe operation of the instrument even in a wet environment. The instrument can be deployed down to a depth of 10 m. No power cable is needed for operation due to the internal rechargeable batteries.

Now with GPS sensor for exact location recording

Features & Informations

Advantages of BenthoTorch fluorescence measurements

  • simultaneous determination of green algae, blue-green and diatoms
  • no sampling or preparation
  • rapid, portable operation
  • result displayed on the instrument, with internal memory for storage


  • EU WFD ecological status assessment
  • restoration / rehabilitation projects
  • environmental monitoring
  • limnological work
  • research and education


Instrument functions

  • start / stop of instrument
  • access to all stored values
  • online display of measurement results
  • input of parameter: measuring time, interval, GPS on/off
  • (re-)calibration of instrument

PC software functions

  • data retrieval and management
  • display and storage of measurement data
  • graphic display of measuring time
  • data export to EXCEL and ASCII files
  • GPS data export to e.g. Google Earth

Technical specification of our BenthoTorch

Description Value
  • concentration of green algae [µg chl-a/cm²]
  • concentration of cyanobacteria [µg chl-a/cm²]
  • concentration of diatoms [µg chl-a/cm²]
  • GPS coordinates
Measuring range 0 - 15 µg chl-a/cm²
Resolution 0.1 µg chl-a/cm²
Weight 1.3 kg
Size (H x Ø) 500 x 60 mm
Power supply 110/230 V - 50/60 Hz - 12V DC
Power input 10 W
Protection class IP68
Depth range 10 m
Interface USB
  • carrying case
  • mains unit
  • manual
  • software
  • hand loop
  • telescopic rod
  • nylon shoulder bag
  • SDI-12 with bbe converter

Subject to alteration!

Available variants of the BenthoTorch


Itemnumber: BG0367.0000

A rapid, handheld spectrofluorometer for the measurement of chlorophyll-a on substrates (green algae, cyanobacteria and diatoms), internal datalogger, internal rechargeable batteries.

Submersible to 10 m.

Measurement range:

  • 0-10 µg chlorophyll-a/cm2
  • resolution 0.2 µg/cm2


  • handheld
  • internal software
  • data transfer to laptop or PC via USB
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Available accessories for the BenthoTorch

Shoulder Bag (ATo/BTo)

Itemnumber: E16156

A handy, lightweight, nylon shoulder bag.

Telescopic Rod (ATo/BTo)

Itemnumber: BG0036.0030

A telescopic rod to operate the AlgaeTorch at a distance (extendable from 0.95 - 2.80 m).

Downloads & Information about the BenthoTorch

Manuals, software and further informations for this product may be available in the internal area for registered users.