Irradiance and nutrient-dependent effects on photosynthetic electron transport in Arctic phytoplankton: A comparison of two chlorophyll fluorescence-based approaches to derive primary photochemistry
We employed Fast Repetition Rate fluorometry for high-resolution mapping of marine phytoplankton photophysiology and primary photochemistry in the Lancaster Sound and Barrow Strait regions of the Canadian Arctic Archipelago in the summer of 2019. Continuous ship-board analysis of chlorophyll a varia...
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ftdoajarticles:oai:doaj.org/article:03c56a5e50684a88a47d46a3410b5f79 2023-05-15T14:28:57+02:00 Irradiance and nutrient-dependent effects on photosynthetic electron transport in Arctic phytoplankton: A comparison of two chlorophyll fluorescence-based approaches to derive primary photochemistry Yayla Sezginer David J. Suggett Robert W. Izett Philippe D. Tortell 2021-01-01T00:00:00Z https://doaj.org/article/03c56a5e50684a88a47d46a3410b5f79 EN eng Public Library of Science (PLoS) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8659313/?tool=EBI https://doaj.org/toc/1932-6203 1932-6203 https://doaj.org/article/03c56a5e50684a88a47d46a3410b5f79 PLoS ONE, Vol 16, Iss 12 (2021) Medicine R Science Q article 2021 ftdoajarticles 2022-12-31T15:49:31Z We employed Fast Repetition Rate fluorometry for high-resolution mapping of marine phytoplankton photophysiology and primary photochemistry in the Lancaster Sound and Barrow Strait regions of the Canadian Arctic Archipelago in the summer of 2019. Continuous ship-board analysis of chlorophyll a variable fluorescence demonstrated relatively low photochemical efficiency over most of the cruise-track, with the exception of localized regions within Barrow Strait, where there was increased vertical mixing and proximity to land-based nutrient sources. Along the full transect, we observed strong non-photochemical quenching of chlorophyll fluorescence, with relaxation times longer than the 5-minute period used for dark acclimation. Such long-term quenching effects complicate continuous underway acquisition of fluorescence amplitude-based estimates of photosynthetic electron transport rates, which rely on dark acclimation of samples. As an alternative, we employed a new algorithm to derive electron transport rates based on analysis of fluorescence relaxation kinetics, which does not require dark acclimation. Direct comparison of kinetics- and amplitude-based electron transport rate measurements demonstrated that kinetic-based estimates were, on average, 2-fold higher than amplitude-based values. The magnitude of decoupling between the two electron transport rate estimates increased in association with photophysiological diagnostics of nutrient stress. Discrepancies between electron transport rate estimates likely resulted from the use of different photophysiological parameters to derive the kinetics- and amplitude-based algorithms, and choice of numerical model used to fit variable fluorescence curves and analyze fluorescence kinetics under actinic light. Our results highlight environmental and methodological influences on fluorescence-based photochemistry estimates, and prompt discussion of best-practices for future underway fluorescence-based efforts to monitor phytoplankton photosynthesis. Article in Journal/Newspaper Arctic Archipelago Arctic Canadian Arctic Archipelago Lancaster Sound Phytoplankton Directory of Open Access Journals: DOAJ Articles Arctic Barrow Strait ENVELOPE(-94.168,-94.168,74.402,74.402) Canadian Arctic Archipelago Lancaster Sound ENVELOPE(-83.999,-83.999,74.218,74.218) |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Medicine R Science Q |
spellingShingle |
Medicine R Science Q Yayla Sezginer David J. Suggett Robert W. Izett Philippe D. Tortell Irradiance and nutrient-dependent effects on photosynthetic electron transport in Arctic phytoplankton: A comparison of two chlorophyll fluorescence-based approaches to derive primary photochemistry |
topic_facet |
Medicine R Science Q |
description |
We employed Fast Repetition Rate fluorometry for high-resolution mapping of marine phytoplankton photophysiology and primary photochemistry in the Lancaster Sound and Barrow Strait regions of the Canadian Arctic Archipelago in the summer of 2019. Continuous ship-board analysis of chlorophyll a variable fluorescence demonstrated relatively low photochemical efficiency over most of the cruise-track, with the exception of localized regions within Barrow Strait, where there was increased vertical mixing and proximity to land-based nutrient sources. Along the full transect, we observed strong non-photochemical quenching of chlorophyll fluorescence, with relaxation times longer than the 5-minute period used for dark acclimation. Such long-term quenching effects complicate continuous underway acquisition of fluorescence amplitude-based estimates of photosynthetic electron transport rates, which rely on dark acclimation of samples. As an alternative, we employed a new algorithm to derive electron transport rates based on analysis of fluorescence relaxation kinetics, which does not require dark acclimation. Direct comparison of kinetics- and amplitude-based electron transport rate measurements demonstrated that kinetic-based estimates were, on average, 2-fold higher than amplitude-based values. The magnitude of decoupling between the two electron transport rate estimates increased in association with photophysiological diagnostics of nutrient stress. Discrepancies between electron transport rate estimates likely resulted from the use of different photophysiological parameters to derive the kinetics- and amplitude-based algorithms, and choice of numerical model used to fit variable fluorescence curves and analyze fluorescence kinetics under actinic light. Our results highlight environmental and methodological influences on fluorescence-based photochemistry estimates, and prompt discussion of best-practices for future underway fluorescence-based efforts to monitor phytoplankton photosynthesis. |
format |
Article in Journal/Newspaper |
author |
Yayla Sezginer David J. Suggett Robert W. Izett Philippe D. Tortell |
author_facet |
Yayla Sezginer David J. Suggett Robert W. Izett Philippe D. Tortell |
author_sort |
Yayla Sezginer |
title |
Irradiance and nutrient-dependent effects on photosynthetic electron transport in Arctic phytoplankton: A comparison of two chlorophyll fluorescence-based approaches to derive primary photochemistry |
title_short |
Irradiance and nutrient-dependent effects on photosynthetic electron transport in Arctic phytoplankton: A comparison of two chlorophyll fluorescence-based approaches to derive primary photochemistry |
title_full |
Irradiance and nutrient-dependent effects on photosynthetic electron transport in Arctic phytoplankton: A comparison of two chlorophyll fluorescence-based approaches to derive primary photochemistry |
title_fullStr |
Irradiance and nutrient-dependent effects on photosynthetic electron transport in Arctic phytoplankton: A comparison of two chlorophyll fluorescence-based approaches to derive primary photochemistry |
title_full_unstemmed |
Irradiance and nutrient-dependent effects on photosynthetic electron transport in Arctic phytoplankton: A comparison of two chlorophyll fluorescence-based approaches to derive primary photochemistry |
title_sort |
irradiance and nutrient-dependent effects on photosynthetic electron transport in arctic phytoplankton: a comparison of two chlorophyll fluorescence-based approaches to derive primary photochemistry |
publisher |
Public Library of Science (PLoS) |
publishDate |
2021 |
url |
https://doaj.org/article/03c56a5e50684a88a47d46a3410b5f79 |
long_lat |
ENVELOPE(-94.168,-94.168,74.402,74.402) ENVELOPE(-83.999,-83.999,74.218,74.218) |
geographic |
Arctic Barrow Strait Canadian Arctic Archipelago Lancaster Sound |
geographic_facet |
Arctic Barrow Strait Canadian Arctic Archipelago Lancaster Sound |
genre |
Arctic Archipelago Arctic Canadian Arctic Archipelago Lancaster Sound Phytoplankton |
genre_facet |
Arctic Archipelago Arctic Canadian Arctic Archipelago Lancaster Sound Phytoplankton |
op_source |
PLoS ONE, Vol 16, Iss 12 (2021) |
op_relation |
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8659313/?tool=EBI https://doaj.org/toc/1932-6203 1932-6203 https://doaj.org/article/03c56a5e50684a88a47d46a3410b5f79 |
_version_ |
1766303067532165120 |