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


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)