LabSTAF Portable Phytoplankton Primary Productivity Instrument

Single Turnover Active Fluorometry (STAF) for measuring phytoplankton primary productivity (PhytoPP)

LabSTAF Is the next generation of STAF-based instrumentation to measure phytoplankton primary productivity. The system incorporates unparalleled sensitivity with a wide dynamic range, allowing for measurements in all environments: from reservoirs and lakes to open ocean.

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Revolutionising primary productivity measurements in the field

LabSTAF Overview

Single Turnover Active Fluorometry (STAF) is widely accepted for non-invasive primary productivity assessment in the field. LabSTAF is the next generation of STAF-based primary productivity instrumentation for measuring phytoplankton primary productivity in all water environments from coastal waters and lakes to the open ocean.

Chelsea’s LabSTAF monitors phytoplankton using the latest in STAF technology. The system combines unparalleled sensitivity with a wide dynamic range, allowing for measurements in extreme oligotrophic waters, open oceans, coastal waters and lakes. The highly automated platform runs continuous Fluorescence Light Curves (FLCs), improving the accuracy of STAF-based PhytoPP assessment for greater precision at low biomass, correction of spectral errors, baseline fluorescence and the package effect.

LabSTAF’s compact and robust unit is ideal for deployment on research vessels and in the lab. A number of features have been specifically incorporated to minimise errors associated with the conversion of STAF data to Phytoplankton including: Seven waveband excitation, dual fluorescence waveband measurement and baseline subtraction.

LabSTAF Features

  • Benchtop instrument to measure primary productivity using fluorescence, giving data for over 50 useful parameters within 15 minutes
  • Ability to generate 2-6 full fluorescent light curves per hour at 8-12 irradiance levels
  • Recognised method of measuring primary productivity in the oceans over wide dynamic ranges including coastal areas and oligotrophic zones
  • Instrumentation validated on many research cruises and mesocosm experiments
  • Full system and accessories supplied as standard to permit automated data generation from an underway system
  • LabSTAF includes a peristaltic pump, solenoid unit and flow-through stirrer unit to provide for mixing, sample exchange and a periodic cleaning cycle.
  • Also included is a Surface Go 2 laptop, pre-installed with the regularly updated RunSTAF software.
  • Data from LabSTAF is interpreted and analysed internally in the included Surface Go
  • Scientific support available from our in house team of scientists

Technical Features

  • Integration of the absorption method for quantifying photosynthesis (Oxborough et al. 2012)
  • Seven measurement wavebands to allow for routine spectral correction based on variable fluorescence (Fv)
  • Dual narrow waveband fluorescence measurement, centered at 685 nm and 730 nm, for automated package effect correction (Boatman et al. 2019)
  • Dual Single Turnover pulse method for the measurement of relaxation phase kinetics
  • Full spectrum blue-enhanced actinic illumination providing up to 2500 µmol photons m-2 s-1
  • Circulating water jacket for the sample chamber, which avoids intersection with optical paths
  • Potential replacement for 14C based photosynthetron measurements
  • Three acquisition modes: automated FLC, manual control and dark flow


  • Analysis of the biochemistry and ecology of aquatic systems
  • Verification of satellite data
  • Facilitates measurement at scales from mesoscale eddies to oceanic fronts
  • Climate change research and modelling
  • Plankton counting
  • Monitoring of algal bloom development and community structure
  • Ecological monitoring to manage water catchments
  • Identify and mitigate sources affecting water quality in catchments
  • Quantitative assessment for the fundamental systems driving the global carbon cycle
  • Measurement of PSII photochemical flux per unit volume (JVPII) to provide an upper limit to PhytoPP at high spatiotemporal scales

LabSTAF Specifications

Power supply 140 – 400 mA at 24 V (3.4 – 9.7 W)
Dimensions (mm) 235 (H) x 320 (W) x 420 (D)
Mass (approx.) 8.1 kg
Sample Chamber 20 mL sample volume with fused silica vertical cylinder, BK7 base
Excitation wavebands (wavelength) 452, 472, 505, 417, 534, 594, 622 nm
Actinic light source Collimated output from 10 – 2400 μmol photons m² s¹ at 12 bit resolution
Detection limit Can resolve Fwith an amplitude equivalent to 0.001 mg m-3 of chlorophyll a
IP rating IP65
" Phytoplankton primary productivity represents ~half of the carbon fixed by photosynthesis on a planetary scale. Reliable measurements are critical for understanding the carbon cycle and tackling climate change.  "

LabSTAF Users

LabSTAF References

Primary production assessment on eco-engineering infrastructures: English Channel case study
P Claquin, B Vivier, M Navon, AM Rusig… – IOP Conference …, 2022 –
Complex Drivers of Primary Production Along a Dystrophic Anthropised Estuary (Seine Estuary–France)
L Serre-Fredj, L Chasselin, O Jolly… – Available at SSRN … –
Optimising Multispectral Active Fluorescence to Distinguish the Photosynthetic Variability of Cyanobacteria and Algae
E Courtecuisse, E Marchetti, K OxboroughPD Hunter… – Sensors, 2023 –
AMT29 Cruise Report
Nina Schuback, Mark Moore, Kevin Oxborough, Alan Wright – Plymouth Marine Science Electronic Archive, 2022 –
Single-Turnover Variable Chlorophyll Fluorescence as a Tool for Assessing Phytoplankton Photosynthesis and Primary Productivity: Opportunities, Caveats and Recommendations
Nina Schuback, Philippe D. Tortell, Ilana Berman-Frank, Douglas A. Campbell, Aurea Ciotti, Emilie Courtecuisse, Zachary K. Erickson, Tetsuichi Fujiki, Kimberly Halsey, Anna E. Hickman, Yannick Huot, Maxime Y. Gorbunov, David J. Hughes, Zbigniew S. Kolber, C. Mark Moore, Kevin Oxborough, Ondřej Prášil, Charlotte M. Robinson, Thomas J. Ryan-Keogh, Greg Silsbe, Stefan Simis, David J. Suggett, Sandy Thomalla and Deepa R. Varkey – Frontiers in Marine Science, 2022 –
Improving the Accuracy of Single Turnover Active Fluorometry (STAF) for the Estimation of Phytoplankton Primary Productivity (PhytoPP)
Tobias G. Boatman, Richard J. Geider and Kevin Oxborough – Frontiers in Marine Science, 2019 –

LabSTAF Applications


The LabSTAF is a portable system designed for use in the laboratory field or on research vessels. You can either run the system with discrete samples or use the flow through accessories to take automated continuous samples (up to 6 per hour), such as an underway system on a research ship. However, our customers have been more innovate and deployed their LabSTAF on buoys and USVs! We are happy to help you set up your system and provide advice, whatever the application!

STAF measurements provide an estimate of electron flux through photosystem II whereas 14C measurements directly estimate carbon fixation. It is generally assumed that four electrons are required to fix one carbon, but this can vary depending on environmental conditions. Further work is being conducted to better understand this relationship and enable more accurate estimation of carbon fixation from electron flux.

The relationship between 14C and STAF measurements can be established within your measurement zone by a dual incubation method, that takes both measurements from the same sample.  Full details of the method are contained within the LabSTAF handbook .

LabSTAF represents a significant update to the well-established combination of FastOcean Fast Repetition Rate fluorometer (FRRf) and Act2 laboratory system. The list of advantages that LabSTAF has over FastOcean plus Act2 includes:

  • More than ten times the sensitivity
  • Much lower optical filter breakthrough
  • Two fluorescence detection wavebands instead of one
  • Seven fluorescence excitation LED wavebands instead of three
  • DC actinic light source providing 10 to > 1600 μmol photons m-2 s-1
  • A circulating water jacket that avoids intersection with all optical paths
  • Increased FLC automation
  • Extended data analysis
  • Improved access to primary data

The increased sensitivity is the result of a switch from 1 μs FRRf 'flashlets' on a 2 μs pitch to a solid excitation pulse from the excitation LEDs, plus a more efficient optical arrangement. An added advantage of the switch from FRRf to a solid pulse is that the same number of data points can be collected in half the time. Consequently, the default Single Turnover (ST) pulse has been shortened from 200 μs (FastOcean) to 100 μs (LabSTAF). The much lower filter breakthrough is the result of the change in optical configuration and the use of better optical filters. The most obvious benefit is lower and more consistent blank values when sampling within extreme oligotrophic regions.

The optical filtering within LabSTAF is much better than it is in FastOcean. Consequently, it can be expected to do a much better job of handling high turbidity and DOC. Turbidity generally increases filter breakthrough by scattering the measuring LED light towards the PMT. Protection against this type of filter breakthrough is at least an order of magnitude better in LabSTAF than FastOcean.

STAF measurements can be adopted to enable higher spatial and temporal resolution of primary productivity estimates with continuing reference back to lower resolution 14C measurements to ‘calibrate’ those estimates.

Single Turnover Fluorometry (STAF) was designed and developed by ocean scientists to make Single Turnover (ST) measurements from optically thin samples, allowing reliable flow through and profiling measurements from oligotrophic waters.  PAM based systems, that use Multiple Turnover (MT) measurements, were designed for working with high optical density terrestrial plants. The long saturation pulse of MT prevents its use in situations where the sample is being exchanged rapidly (e.g. flow-through or profiling systems) while the long interval between saturation pulses severely limits the signal to noise ratio, severely compromising the detection limit of MT based systems.

If you would like to book a demonstration, please contact us. Alternatively, please visit us at a variety of ocean conferences and exhibitions throughout the year.

LabSTAF Training, Service and Support

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