The Emitter Detector Fibre-optics Unit PHYTO-EDF is connected to the standard Power-and-Control-Unit PHYTO-C of the PHYTO-PAM Phytoplankton Analyser. All electro-optical components are contained in a single compact housing, with special fibre-optics (9-armed) forming the optical link to the sample. The fibre-optics can be mounted on a stand with base plate.
The compact emitter-detector box houses 4 different LED measuring light sources (470 nm, 520 nm, 645 nm and 665 nm), the actinic LED light sources (655 nm) and a photomultiplier detector. All LED light sources are equipped with miniature fibre couplers and short-pass filters (λ < 695 nm). The detector is protected by a special long-pass filter set (λ > 710 nm) which is optimised for low background signal.
|Power-and-Control Unit PHYTO-C|
|User interface:||Computer with Windows XP or Vista operating system and PhytoWin software; connection via RS 232 or separate USB to RS232 adapter (hardware provided)|
|Data output:||Display and print-out via PC; analogue output of four channels (original fluorescence data), 0 to 5 V|
|Power supply:||Built-in rechargeable sealed lead-acid battery 12 V/7.2 Ah; Battery Charger MINI-PAM/L (100 to 240 V AC)|
|Power consumption:||Basic operation 350 mA; with all LED light sources turned on, max. 800 mA|
|Dimensions:||31 cm x 16 cm x 33.5 cm (W x H x D), with carrying handle|
|Emitter-Detector-Fiberoptics Unit PHYTO-EDF|
|Design:||Metal housing with cables connecting to the Power-and-Control-Unit PHYTO-C; containing measuring and actinic/saturation pulse LEDs, miniature fibre couplers with SMA-fibre connectors, photomultiplier and pulse preamplifier; separate 9-armed fibre-optics|
|Dimensions:||115 mm x 90 mm x 95 mm (L x W x H)|
|Weight:||Approx. 600 g|
|Measuring LEDs:||Total of 4 LEDs for pulse modulated measuring light peaking at 470, 520, 645 and 665 nm, focused on entrance of 1 mm Ø single plastic fibres with SMA-connectors|
|Actinic LEDs:||Total of 4 LEDs for actinic light/saturation pulses peaking at 655 nm focused on entrance of 1 mm Ø single plastic fibers with SMA-connectors; actinic intensity up to 1800 μmol m-2 s-1 of photosynthetically active radiation (PAR); Saturation Pulse intensity up to 3500 μmol m-2 s-1|
|Signal detection:||Photomultiplier detector based on a photosensor module by Hamamatsu with high red sensitivity; featuring pulse preamplifier and automatic overload switch-off; fluorescence detection at λ>710 nm; optimised for low background signal by special filter combination|
|Fibre optics:||8 arms with 1 mm Ø single plastic fibres with SMA-adaptors to be connected to measuring light and actinic light connectors on top side of emitter-detector box; central 1.5 mm Ø fibre with adapter to detector input; length 105 cm; joint end with special endpiece featuring 4 mm Ø perspex light mixing rod, length 50 mm|
|Stand with Base Plate ST-101|
|Heavy base plate made from laminated wood (39.5 cm x 30 cm x 2 cm); with stand bar Ø 15 mm, height 76.5 cm (dividable in two parts; weight 2.8 kg; featuring special holder for fibreoptics endpiece, dark-box for shielding sample from ambient light|
|Mini Quantum Sensor US-MQS/B|
|Design:||Cylindrical housing with 14 mm diameter, height 16 mm. Diffusor diameter 5 mm, 3 m cable and BNC connector|
|Sensor:||Cosine corrected selective PAR sensor for measuring range 0 to 20000 μmol m-2 s-1. Shipped together with the Adapter Set MQS-B/A for the calibration of the internal light list of the PHYTO-PAM FIBRE version and WATER-PAM FIBRE version. The sensor part (MQS-B) can be directly connected to the Universal Light Meter ULM-500|
The FIBRE 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 fibre-optics end piece.
The latter consists of a 4 mm Ø perspex rod, the front of which 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 centre of fibre bundle). While measurements are possible with the perspex rod being submerged in algae suspensions, the sensitivity is distinctly lower than with the MODULAR version or the PHYTO-PAM-II COMPACT version. For toxicological work , a 4 mm Ø quartz glass rod (EDF-Q) is available.
Functionally the four wavelength PHYTO-PAM Fibre version displays the same features as the MODULAR version. Chlorophyll fluorescence is excited by microsecond LED-light pulses alternating between four different wavelengths (measuring light) and the photosynthetic activity is assessed using red actinic light and saturation pulses.
The differently coloured measuring light is absorbed to different extents by the three major types of phytoplankton (green algae, diatoms/dinoflagellates and cyanobacteria) leading to characteristic differences in the fluorescence responses.
After system calibration with the separate phytoplankton groups, the relative contents of these groups can be determined in unknown samples by computer-aided de-convolution using the PhytoWin software. The photosynthetic properties of these groups are characterised by their effective PSII quantum yields, relative electron transport rates (ETR) and light response curves.