AutoSTAF Deployable Primary Productivity

Overview

Single Turnover Active Fluorometry (STAF) is already well established as a method for the non-invasive assessment of phytoplankton photosynthesis. AutoSTAF is the deployable equivalent of Chelsea’s existing LabSTAF system, incorporating fully automated spectral analysis, dual waveband package effect correction and Fluorescence Light Curves (FLCs). This combination of features makes AutoSTAF ideal for the in-situ assessment of primary productivity.

Chelsea’s AutoSTAF combines unparalleled sensitivity with a wide dynamic range, allowing for measurements in extreme oligotrophic waters, open oceans, coastal waters and lakes. AutoSTAF’s compact and robust unit is ideal for deployment on moorings and similar platforms. A number of features have been specifically incorporated to minimise errors associated with the conversion of STAF data to PhytoPP including: seven waveband excitation, dual fluorescence waveband measurement and baseline subtraction.

The combination of AutoSTAF and Deployable Control Unit (DCU) provides a robust system for deploying on moorings and other submerged platforms. A number of features have been specifically incorporated to minimise errors associated with the quantitative evaluation of PSII photochemistry per unit volume, per unit time. This list includes seven waveband excitation, for spectral evaluation, and dual waveband fluorescence measurement for package effect correction. Along with the ability to run FLCs, with automated protocol adjustment, these features greatly increases the value of AutoSTAF for primary productivity assessment.

WHAT ARE THE CURRENT METHODS?

Traditional methods of measuring primary productivity involve a compromise between the accuracy of the data and the temporal and spatial resolution

Satellite remote sensing methodology is the broadest large-scale method, but produces large errors, requires validation and is unable to probe below the surface
Traditional methods such as 14C fixation are slow, expensive laboratory-based processes requiring handling and training protocols for radioisotopes

CHELSEA’S SOLUTION

AutoSTAF builds on the LabSTAF lab-based instrument from Chelsea Technologies enabling in-situ automated analysis. The combination of AutoSTAF and DCU provides a deployable platform for measurements that have historically been restricted to the laboratory environment.

Deployable to 600m
Ideal for use on moorings, large AUVs and similar
Unparalleled sensitivity allowing for measurements in extreme oligotrophic water
Fully automated acquisition for continuous measurements
Wide dynamic range providing reliable measurements in open oceans and lakes
Advanced corrections as standard: seven waveband excitation, dual fluorescence waveband measurement and baseline subtraction

Features & Applications

AutoSTAF Features

In water assessment of phytoplankton photosynthesis using latest STAF technology
Fully automated system includes an optional Spectral PAR (SPAR) sensor for ambient light assessment
Wide dynamic range providing reliable measurements in open oceans and lake
Greatly improved accuracy when compared with satellite data
Greatly improved spatial and temporal resolution when compared with 14C-fixation
Advanced spectral evaluation using seven waveband excitation
Package effect correction using dual waveband fluorescence measurement
Deployable to 600m on a variety of platforms

AutoSTAF Applications

Measurement of PSII photochemical flux per unit volume (JVPII) to provide an upper limit to primary productivity at high spatial and temporal scales
Carbon cycle assessment
Analysis of the biochemistry and ecology of aquatic systems
Verification of satellite data
Climate change research and modelling
Monitoring of algal bloom development and community structure
Ecological monitoring to manage water catchments
Identify and mitigate sources affecting water quality in catchments

AutoSTAF Technical Features

Integration of the absorption method for the assessment of photosynthesis and primary productivity per unit volume, per unit time (Oxborough et al. 2012)
Seven measurement wavebands to allow for routine spectral correction based on variable fluorescence (FV)
Comparison of Fv-based and PII-based spectral data provides valuable qualitative information on community structure
Dual narrow waveband fluorescence measurement 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 > 1600 µmol photons m-2 s-1
Circulating sample chamber water jacket which avoids intersection with all optical paths
Potential replacement for 14C-based photosynthetron measurements

Specifications

Power requirements	140 – 400 mA, 24 V, 3.4 – 9.7 W
Excitation wavebands (wavelength)	452, 472, 505, 417, 534, 594, 622 nm
Actinic light source	Collimated output from 10 – 2400 μmol photons m^–² s^–¹ at 12 bit resolution
Detection limit	Can resolve F_∨with an amplitude equivalent to 0.001 mg m^-3of chlorophyll a
Depth rating	600m

Downloads

AutoSTAF brochure

FAQs

Why use Single Turnover Active Fluorometry (STAF)?

The application of STAF has revolutionized our general understanding of phytoplankton physiology in oceanic systems over more than twenty years and, with recent technological and theoretical developments, has become recognized as an enabling technology from non-destructive in situ measurements of Phytoplankton Primary Productivity.

Photochemistry by Photosystem II (PSII) is the ultimate source of energy for PhytoPP. STAF can be used to measure PSII photochemical flux per unit volume (JVpII). This parameter is strongly correlated with oxygen evolution by PSII and provides an upper limit to PhytoPP. AutoSTAF can be used on much wider spatiotemporal scales and either 14C fixation or O2 evolution and at much lower biomass.