The FIBER Version is a four-wavelength instrument and provides differential analysis of the photosynthetic performance of up to three algae groups in one sample.

The Emitter Detector Fiberoptics Unit PHYTO-EDF is an emitter-detector housing 4 different LED measuring light sources (470 nm, 520 nm, 645 nm and 665 nm), the actinic LED light source (655 nm) and a photomultiplier detector. The special (9-armed) fiberoptic forms the optical link between PHYTO-EDF and the sample.

The FIBER version is well-suited for highly sensitive assessment of photosynthetic activity on surfaces, as e.g. periphyton, microphytobenthos and microbial mats. Due to the use of a photomultiplier, large signals are obtained even at low sample densities. On the other hand, at high gain the photomultiplier has to be protected from ambient light. For this purpose, as well as for dark-acclimation of the sample, a darkening-box is provided which covers the sample and encloses the fiberoptics endpiece.

A basic system of the PHYTO-PAM FIBER version consists of the following components:

  • Power-and-Control-Unit PHYTO-C with internal battery and USB-RS 232 port for communication with an external PC
  • Emitter-Detector-Fiberoptics Unit PHYTO-EDF consisting of a 9-armed fiberoptics (length 105 cm) with 4 mm Ø Perspex rod, LED array:  measuring light sources (470 nm, 520 nm, 645 nm and 665 nm), actinic LED light source (655 nm) and a photomultiplier detector

The  4 mm Ø Perspex rod at the fiber tip is in contact with the sample surface via a thin layer of water. The Perspex rod serves the purpose of mixing the different types of light and to guide the fluorescence to the detector fiber (1.5 mm Ø, in center of fiber bundle). While measurements are possible with the Perspex rod being submerged in algae suspensions, the sensitivity of PHYTO-PAM FIBER version is distinctly lower than the sensitivity of PHYTO-PAM-II instruments. For toxicological work, a 4 mm Ø quartz glass rod (EDF-Q) is available.