Act2 Laboratory-Based System

The Act2 Laboratory System is a highly automated system for probing oxygenic photosynthesis by phytoplankton and assessing primary productivity by running fluorescence light curves.
The system combines the FastOcean Fast Repetition Rate fluorometer (FRRf) and Act2 System A to create a powerful laboratory tool. The Act2 system increments incident photon irradiance in small incremental steps to cover a wide dynamic range - up to and above full sunlight. The Act2 FLC sample chamber provides full spectrum actinic illumination from filtered white LEDs, with the option to swap in 450 nm LED units. This allows for a spectral match to be made between the FRRf and actinic illumination, allowing for direct comparison of FRRf and FLC-derived data.

The Act2 system provides an unparalleled level of automation, including real-time derivation of relative photosynthesis – photon irradiance (rPE) parameters (including alpha and Ek) from FLC data. These data can be used, by the controlling software, to

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Features & Applications


  • Fully programmable protocol design for fluorescence light curves (FLCs) including sample exchange between successive runs
  • Options to duplicate the FLC protocol as oxygen light curves (OLCs) and estimate PSII reaction centre concentration through flash O2 measurements, when combined with a Hansatech Oxygraph system
  • Fine control of photon irradiance(E) during FLCs and OLCs (down to 1 µmol photons m-2 s-1 at low E values)
  • Up to full sunlight intensity during FLCs and OLCs (>2,000 µmol photons m-2 s-1)
  • Saturating, single turnover flashes of 160 µs duration at 20,000 µmol photons m-2 s-1 for flash O2 measurements
  • Fully automated changes to FLC protocol design within long-term experiments
  • Optional solenoid system allows for programmable switching between sample sources
  • High level of automation and operational stability, making it suitable for use in autonomously deployed systems


  • Continuous running of fluorescence light curves (FLC) with automated sampling from one or more phytoplankton cultures
  • Replacement of 14C-based photosynthetron systems for generating primary productivity data
  • Oxygen light curves (OLCs) and estimation of PSII concentration (when combined with Hansatech Oxygraph system)


FastOcean FRR fluorometer

Excitation LED Channels 3 x 6 custom-made LEDs, centred at 450, 530 and 624 nm.
LED filtering 630 nm short-pass filter (>OD6 between 655 and 750 nm).
Signal detection NIR-enhanced PMT with stabilised power supply
Detection filtering 2 x 3 mm RG665 glass filters plus 682 nm, 30 nm half bandwidth interference filter
Dynamic range 16-bit ADC provides an effective 15-bit range at each PMT eht setting. The total dynamic range is at least five orders of magnitude
Power requirements 18 to 36 VDC operating range
Protected to 72 VDC
4.8 W continuous, 5 W peak
Ambient temperature -10 ° C to 50 ° C
Dimensions Ø 88 mm x 284mm (excluding connectors)

Act2 Controller

Dimensions 198 mm (w) x 108 mm (d) x 62 mm (h)
PC Connection USB (cable supplied)
Environmental rating IP68 (main unit only)
Power input 28 V (power brick supplied)
Outputs 1 x USB to PC, 1 x FastOcean, 4 x LED units, 2 x peristaltic pumps, 3 x solenoid valves

LED units (white or blue)

Increments <4 µmol photons m-2 s-1
Maximum output (FLCs/OLCs) >2,000 µmol photons m-2 s-1
Maximum output (Flash O2) >20,000 µmol photons m-2 s-1
Environmental rating IP68

Accessories and Related Products

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