Diel quenching of Southern Ocean phytoplankton fluorescence is related to iron limitation
Evaluation of photosynthetic competency in time and space is critical for better estimates and models of oceanic primary productivity. This is especially true for areas where the lack of iron (Fe) limits phytoplankton productivity, such as the Southern Ocean. Assessment of photosynthetic competency...
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ftinfoscience:oai:infoscience.epfl.ch:276166 2023-05-15T18:25:16+02:00 Diel quenching of Southern Ocean phytoplankton fluorescence is related to iron limitation Schallenberg, Christina Strzepek, Robert F. Schuback, Nina Clementson, Lesley A. Boyd, Philip W. Trull, Thomas W. 2020-03-11T01:26:22Z https://doi.org/10.5194/bg-17-793-2020 https://infoscience.epfl.ch/record/276166/files/bg-17-793-2020.pdf http://infoscience.epfl.ch/record/276166 unknown doi:10.5194/bg-17-793-2020 isi:000515166900002 https://infoscience.epfl.ch/record/276166/files/bg-17-793-2020.pdf http://infoscience.epfl.ch/record/276166 http://infoscience.epfl.ch/record/276166 Text 2020 ftinfoscience https://doi.org/10.5194/bg-17-793-2020 2023-02-13T22:59:12Z Evaluation of photosynthetic competency in time and space is critical for better estimates and models of oceanic primary productivity. This is especially true for areas where the lack of iron (Fe) limits phytoplankton productivity, such as the Southern Ocean. Assessment of photosynthetic competency on large scales remains challenging, but phytoplankton chlorophyll a fluorescence (ChlF) is a signal that holds promise in this respect as it is affected by, and consequently provides information about, the photosynthetic efficiency of the organism. A second process affecting the ChlF signal is heat dissipation of absorbed light energy, referred to as non-photochemical quenching (NPQ). NPQ is triggered when excess energy is absorbed, i.e. when more light is absorbed than can be used directly for photosynthetic carbon fixation. The effect of NPQ on the ChlF signal complicates its interpretation in terms of photosynthetic efficiency, and therefore most approaches relating ChlF parameters to photosynthetic efficiency seek to minimize the influence of NPQ by working under conditions of sub-saturating irradiance. Here, we propose that NPQ itself holds potential as an easily acquired optical signal indicative of phytoplankton physiological state with respect to Fe limitation. We present data from a research voyage to the Subantarctic Zone south of Australia. Incubation experiments confirmed that resident phytoplankton were Fe-limited, as the maximum quantum yield of primary photochemistry, F-v/F-m, measured with a fast repetition rate fluorometer (FRRf), increased significantly with Fe addition. The NPQ "capacity" of the phytoplankton also showed sensitivity to Fe addition, decreasing with increased Fe availability, confirming previous work. The fortuitous presence of a remnant warm-core eddy in the vicinity of the study area allowed comparison of fluorescence behaviour between two distinct water masses, with the colder water showing significantly lower F-v/F-m than the warmer eddy waters, suggesting a difference in Fe ... Text Southern Ocean EPFL Infoscience (Ecole Polytechnique Fédérale Lausanne) Southern Ocean Biogeosciences 17 3 793 812 |
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EPFL Infoscience (Ecole Polytechnique Fédérale Lausanne) |
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ftinfoscience |
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description |
Evaluation of photosynthetic competency in time and space is critical for better estimates and models of oceanic primary productivity. This is especially true for areas where the lack of iron (Fe) limits phytoplankton productivity, such as the Southern Ocean. Assessment of photosynthetic competency on large scales remains challenging, but phytoplankton chlorophyll a fluorescence (ChlF) is a signal that holds promise in this respect as it is affected by, and consequently provides information about, the photosynthetic efficiency of the organism. A second process affecting the ChlF signal is heat dissipation of absorbed light energy, referred to as non-photochemical quenching (NPQ). NPQ is triggered when excess energy is absorbed, i.e. when more light is absorbed than can be used directly for photosynthetic carbon fixation. The effect of NPQ on the ChlF signal complicates its interpretation in terms of photosynthetic efficiency, and therefore most approaches relating ChlF parameters to photosynthetic efficiency seek to minimize the influence of NPQ by working under conditions of sub-saturating irradiance. Here, we propose that NPQ itself holds potential as an easily acquired optical signal indicative of phytoplankton physiological state with respect to Fe limitation. We present data from a research voyage to the Subantarctic Zone south of Australia. Incubation experiments confirmed that resident phytoplankton were Fe-limited, as the maximum quantum yield of primary photochemistry, F-v/F-m, measured with a fast repetition rate fluorometer (FRRf), increased significantly with Fe addition. The NPQ "capacity" of the phytoplankton also showed sensitivity to Fe addition, decreasing with increased Fe availability, confirming previous work. The fortuitous presence of a remnant warm-core eddy in the vicinity of the study area allowed comparison of fluorescence behaviour between two distinct water masses, with the colder water showing significantly lower F-v/F-m than the warmer eddy waters, suggesting a difference in Fe ... |
format |
Text |
author |
Schallenberg, Christina Strzepek, Robert F. Schuback, Nina Clementson, Lesley A. Boyd, Philip W. Trull, Thomas W. |
spellingShingle |
Schallenberg, Christina Strzepek, Robert F. Schuback, Nina Clementson, Lesley A. Boyd, Philip W. Trull, Thomas W. Diel quenching of Southern Ocean phytoplankton fluorescence is related to iron limitation |
author_facet |
Schallenberg, Christina Strzepek, Robert F. Schuback, Nina Clementson, Lesley A. Boyd, Philip W. Trull, Thomas W. |
author_sort |
Schallenberg, Christina |
title |
Diel quenching of Southern Ocean phytoplankton fluorescence is related to iron limitation |
title_short |
Diel quenching of Southern Ocean phytoplankton fluorescence is related to iron limitation |
title_full |
Diel quenching of Southern Ocean phytoplankton fluorescence is related to iron limitation |
title_fullStr |
Diel quenching of Southern Ocean phytoplankton fluorescence is related to iron limitation |
title_full_unstemmed |
Diel quenching of Southern Ocean phytoplankton fluorescence is related to iron limitation |
title_sort |
diel quenching of southern ocean phytoplankton fluorescence is related to iron limitation |
publishDate |
2020 |
url |
https://doi.org/10.5194/bg-17-793-2020 https://infoscience.epfl.ch/record/276166/files/bg-17-793-2020.pdf http://infoscience.epfl.ch/record/276166 |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
http://infoscience.epfl.ch/record/276166 |
op_relation |
doi:10.5194/bg-17-793-2020 isi:000515166900002 https://infoscience.epfl.ch/record/276166/files/bg-17-793-2020.pdf http://infoscience.epfl.ch/record/276166 |
op_doi |
https://doi.org/10.5194/bg-17-793-2020 |
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Biogeosciences |
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17 |
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3 |
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793 |
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812 |
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1766206595083010048 |