Phytoplankton Primary Productivity (PhytoPP) forms the base of the marine food chain and represents approximately half of the carbon fixed by photosynthesis on a planetary scale.
PhytoPP is an extremely dynamic process that responds to a number of environmental drivers including light, temperature and nutrients. Many of these drivers vary greatly over multiple spatial and temporal scales in the oceans. Single Turnover Active Fluorometry (STAF) has potential for assessment of PhytoPP on much wider spatial and temporal scales than is possible with more direct methods such as 14C fixation or O2 evolved through water oxidation.
This seminar will provide an overview of ongoing technological and theoretical work to improve the accuracy and precision of STAF-based measurements of photosystem II photochemical flux per unit volume (JVPII) which provides the reducing power for PhytoPP. Elements covered include:
- the development of STAF systems for generating fully automated relative photosynthesis vs photon irradiance (rPE) curves;
- a new STAF-based approach to spectral correction under extreme oligotrophic conditions;
- correcting for baseline fluorescence and;
- using dual waveband STAF measurements to correct for the package effect.
An important deliverable from this work is a compact, low-powered and fully autonomous STAF system for assessment of PhytoPP that can be deployed on Marine Autonomous Systems (MASs). A practical demonstration of a lab-based version of this system (LabSTAF) will be run after the seminar.