The Photophysiological Response of Nitrogen-Limited Phytoplankton to Episodic Nitrogen Supply Associated With Tropical Instability Waves in the Equatorial Atlantic
In the Equatorial Atlantic nitrogen availability is assumed to control phytoplankton dynamics. However, in situ measurements of phytoplankton physiology and productivity are surprisingly sparse in comparison with the North Atlantic. In addition to the formation of the Equatorial cold tongue in the b...
Published in: | Frontiers in Marine Science |
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2022
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Online Access: | https://doi.org/10.3389/fmars.2021.814663 https://nbn-resolving.org/urn:nbn:de:gbv:8:3-2022-00112-3 https://macau.uni-kiel.de/receive/macau_mods_00002445 https://macau.uni-kiel.de/servlets/MCRFileNodeServlet/macau_derivate_00003565/fmars-08-814663.pdf |
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ftunivkiel:oai:macau.uni-kiel.de:macau_mods_00002445 2024-06-23T07:55:15+00:00 The Photophysiological Response of Nitrogen-Limited Phytoplankton to Episodic Nitrogen Supply Associated With Tropical Instability Waves in the Equatorial Atlantic Sherman, Jonathan Subramaniam, Ajit Gorbunov, Maxim Y. Fernández-Carrera, Ana Kiko, Rainer Brandt, Peter Falkowski, Paul G. 2022 https://doi.org/10.3389/fmars.2021.814663 https://nbn-resolving.org/urn:nbn:de:gbv:8:3-2022-00112-3 https://macau.uni-kiel.de/receive/macau_mods_00002445 https://macau.uni-kiel.de/servlets/MCRFileNodeServlet/macau_derivate_00003565/fmars-08-814663.pdf eng eng Frontiers in Marine Science -- 2296-7745 https://doi.org/10.3389/fmars.2021.814663 https://nbn-resolving.org/urn:nbn:de:gbv:8:3-2022-00112-3 https://macau.uni-kiel.de/receive/macau_mods_00002445 https://macau.uni-kiel.de/servlets/MCRFileNodeServlet/macau_derivate_00003565/fmars-08-814663.pdf https://creativecommons.org/licenses/by/4.0/ info:eu-repo/semantics/openAccess article ScholarlyArticle ddc:550 Published Version phytoplankton photophysiology variable fluorescence fluorescence lifetimes Equatorial Atlantic tropical instability waves (TIWs) article Text doc-type:Article 2022 ftunivkiel https://doi.org/10.3389/fmars.2021.814663 2024-06-12T14:18:24Z In the Equatorial Atlantic nitrogen availability is assumed to control phytoplankton dynamics. However, in situ measurements of phytoplankton physiology and productivity are surprisingly sparse in comparison with the North Atlantic. In addition to the formation of the Equatorial cold tongue in the boreal summer, tropical instability waves (TIWs) and related short-term processes may locally cause episodic events of enhanced nutrient supply to the euphotic layer. Here, we assess changes in phytoplankton photophysiology in response to such episodic events as well as short-term nutrient addition experiments using a pair of custom-built fluorometers that measure chlorophyll a (Chl a) variable fluorescence and fluorescence lifetimes. The fluorometers were deployed during a transatlantic cruise along the Equator in the fall of 2019. We hypothesized that the Equatorial Atlantic is nitrogen-limited, with an increasing degree of limitation to the west where the cold tongue is not prominent, and that infrequent nitrate injection by TIW related processes are the primary source alleviating this limitation. We further hypothesized phytoplankton are well acclimated to the low levels of nitrogen, and once nitrogen is supplied, they can rapidly utilize it to stimulate growth and productivity. Across three TIW events encountered, we observed increased productivity and chlorophyll a concentration concurrent with a decreased photochemical conversion efficiency and overall photophysiological competency. Moreover, the observed decrease in photosynthetic turnover rates toward the western section suggested a 70% decrease in growth rates compared to their maximum values under nutrient-replete conditions. This decrease aligned with the increased growth rates observed following 24 h incubation with added nitrate in the western section. Article in Journal/Newspaper North Atlantic MACAU: Open Access Repository of Kiel University Frontiers in Marine Science 8 |
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MACAU: Open Access Repository of Kiel University |
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ftunivkiel |
language |
English |
topic |
article ScholarlyArticle ddc:550 Published Version phytoplankton photophysiology variable fluorescence fluorescence lifetimes Equatorial Atlantic tropical instability waves (TIWs) |
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article ScholarlyArticle ddc:550 Published Version phytoplankton photophysiology variable fluorescence fluorescence lifetimes Equatorial Atlantic tropical instability waves (TIWs) Sherman, Jonathan Subramaniam, Ajit Gorbunov, Maxim Y. Fernández-Carrera, Ana Kiko, Rainer Brandt, Peter Falkowski, Paul G. The Photophysiological Response of Nitrogen-Limited Phytoplankton to Episodic Nitrogen Supply Associated With Tropical Instability Waves in the Equatorial Atlantic |
topic_facet |
article ScholarlyArticle ddc:550 Published Version phytoplankton photophysiology variable fluorescence fluorescence lifetimes Equatorial Atlantic tropical instability waves (TIWs) |
description |
In the Equatorial Atlantic nitrogen availability is assumed to control phytoplankton dynamics. However, in situ measurements of phytoplankton physiology and productivity are surprisingly sparse in comparison with the North Atlantic. In addition to the formation of the Equatorial cold tongue in the boreal summer, tropical instability waves (TIWs) and related short-term processes may locally cause episodic events of enhanced nutrient supply to the euphotic layer. Here, we assess changes in phytoplankton photophysiology in response to such episodic events as well as short-term nutrient addition experiments using a pair of custom-built fluorometers that measure chlorophyll a (Chl a) variable fluorescence and fluorescence lifetimes. The fluorometers were deployed during a transatlantic cruise along the Equator in the fall of 2019. We hypothesized that the Equatorial Atlantic is nitrogen-limited, with an increasing degree of limitation to the west where the cold tongue is not prominent, and that infrequent nitrate injection by TIW related processes are the primary source alleviating this limitation. We further hypothesized phytoplankton are well acclimated to the low levels of nitrogen, and once nitrogen is supplied, they can rapidly utilize it to stimulate growth and productivity. Across three TIW events encountered, we observed increased productivity and chlorophyll a concentration concurrent with a decreased photochemical conversion efficiency and overall photophysiological competency. Moreover, the observed decrease in photosynthetic turnover rates toward the western section suggested a 70% decrease in growth rates compared to their maximum values under nutrient-replete conditions. This decrease aligned with the increased growth rates observed following 24 h incubation with added nitrate in the western section. |
format |
Article in Journal/Newspaper |
author |
Sherman, Jonathan Subramaniam, Ajit Gorbunov, Maxim Y. Fernández-Carrera, Ana Kiko, Rainer Brandt, Peter Falkowski, Paul G. |
author_facet |
Sherman, Jonathan Subramaniam, Ajit Gorbunov, Maxim Y. Fernández-Carrera, Ana Kiko, Rainer Brandt, Peter Falkowski, Paul G. |
author_sort |
Sherman, Jonathan |
title |
The Photophysiological Response of Nitrogen-Limited Phytoplankton to Episodic Nitrogen Supply Associated With Tropical Instability Waves in the Equatorial Atlantic |
title_short |
The Photophysiological Response of Nitrogen-Limited Phytoplankton to Episodic Nitrogen Supply Associated With Tropical Instability Waves in the Equatorial Atlantic |
title_full |
The Photophysiological Response of Nitrogen-Limited Phytoplankton to Episodic Nitrogen Supply Associated With Tropical Instability Waves in the Equatorial Atlantic |
title_fullStr |
The Photophysiological Response of Nitrogen-Limited Phytoplankton to Episodic Nitrogen Supply Associated With Tropical Instability Waves in the Equatorial Atlantic |
title_full_unstemmed |
The Photophysiological Response of Nitrogen-Limited Phytoplankton to Episodic Nitrogen Supply Associated With Tropical Instability Waves in the Equatorial Atlantic |
title_sort |
photophysiological response of nitrogen-limited phytoplankton to episodic nitrogen supply associated with tropical instability waves in the equatorial atlantic |
publishDate |
2022 |
url |
https://doi.org/10.3389/fmars.2021.814663 https://nbn-resolving.org/urn:nbn:de:gbv:8:3-2022-00112-3 https://macau.uni-kiel.de/receive/macau_mods_00002445 https://macau.uni-kiel.de/servlets/MCRFileNodeServlet/macau_derivate_00003565/fmars-08-814663.pdf |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
Frontiers in Marine Science -- 2296-7745 https://doi.org/10.3389/fmars.2021.814663 https://nbn-resolving.org/urn:nbn:de:gbv:8:3-2022-00112-3 https://macau.uni-kiel.de/receive/macau_mods_00002445 https://macau.uni-kiel.de/servlets/MCRFileNodeServlet/macau_derivate_00003565/fmars-08-814663.pdf |
op_rights |
https://creativecommons.org/licenses/by/4.0/ info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.3389/fmars.2021.814663 |
container_title |
Frontiers in Marine Science |
container_volume |
8 |
_version_ |
1802647751214759936 |