Autonomous measurement of phytoplankton physiology and productivity using fast repetition rate fluorometry
department or school: Science, Faculty of
department or school: Earth, Ocean and Atmospheric Sciences, Department of
data provider: DSpace
degree campus: UBCV
creator: Sezginer, Yayla
issued: 2025-04-25T18:26:42Z
issued: 2025
related degree: Doctor of Philosophy - PhD
degree grantor: University of British Columbia
description: Through photosynthesis, phytoplankton form the base of marine food webs and drive atmospheric CO₂ uptake through the marine biological carbon pump. Monitoring phytoplankton photosynthetic responses to changing environmental conditions is thus critical to predicting ecosystem feedbacks to climate change. Fast Repetition Rate fluorometry (FRRF) offers rapid measurements of phytoplankton photo-physiology and photosynthetic electron transport rates (ETR), which represent the ultimate source of metabolic energy for carbon fixation. This thesis aims to address several physiological and methodological considerations that presently limit the widespread use of FRRF for high resolution in-situ measurements of phytoplankton ETR. These challenges include diverging approaches to calculate ETR (Chapter 2), the influence of pre-measurement sample handling practices and variable photo-acclimation states on ETR measurements (Chapter 3), and variability in the stoichiometry between ETR and downstream carbon fixation (Chapter 4). The field-based studies presented in this work illustrate how natural light and nutrient gradients influence photo-physiology, FRRF signatures and their interpretation. Results presented in Chapter 2 reveal that the coherence between ETR estimates derived from different algorithms varies with underlying phytoplankton photo-physiology. Additionally, ETR estimates are directly affected by photoprotective non-photochemical quenching (NPQ) that dissipates excess absorbed photo-energy as heat. Chapter 3 investigates the effects of photo-physiology and photo-acclimation states on NPQ relaxation time-scales, providing useful insights for field protocol design for high resolution ETR acquisition. In addition to NPQ, phytoplankton mitigate dangerous accumulation of reductant by diverting electrons towards alternative sinks, decoupling electron transport rates from downstream carbon fixation. Chapter 4 illustrates how this effect manifests as a hyperbolic relationship …
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/90804
note: AUTONOMOUS MEASUREMENT OF PHYTOPLANKTON PHYSIOLOGY AND PRODUCTIVITY USING FAST REPETITION RATE FLUOROMETRY by Yayla Sezginer B.Sc., The University of California, Berkeley, 2019 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES (Oceanography) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) April 2025 © Yayla Sezginer, 2025 ii The following individuals certify that they have read, and recommend to the Faculty of Graduate and Postdoctoral Studies for acceptance, the dissertation entitled: Autonomous measurement of phytoplankton physiology and productivity using Fast Repetition Rate Fluorometry submitted by Yayla Sezginer in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Oceanography. Examining Committee: Philippe Tortell, Professor, Earth Oceans and Atmospheric Science, UBC (Supervisor) Douglas Campbell, Professor, Ecophysiology, Mount Allison University (Supervisory Committee Member) Maite Maldonaldo, Professor, Earth Oceans and Atmospheric Science, UBC (Supervisory Committee Member) Sean Crowe, Professor, Earth Oceans and Atmospheric Science, UBC (University Examiner) Robert Guy, Professor, Forestry, UBC (University Examiner) Sven Kranz, Professor, BioSciences, Rice University (External Examiner) Additional Supervisory Committee Members: Patrick Martone, Professor, Botany, UBC (Supervisory Committee Member) iii Abstract Through photosynthesis, phytoplankton form the base of marine food webs and drive atmospheric CO2 uptake through the marine biological carbon pump. Monitoring phytoplankton photosynthetic responses to changing environmental conditions is thus critical to predicting ecosystem feedbacks to climate change. Fast Repetition Rate fluorometry (FRRF) offers rapid measurements of phytoplankton photo-physiology and photosynthetic electron transport rates (ETR), which represent the ultimate source of metabolic energy for carbon…
has type: Thesis/Dissertation
date issued: 2025-05
is shown at: 10.14288/1.0448589
language: eng
degree discipline: Oceanography
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
contributor: Tortell, Philippe Daniel, 1972-
type: Text
identifier URI: http://hdl.handle.net/2429/90804