Photosynthetic Carbon Assimilation and Electron Transport Rates in Two Symbiont-Bearing Planktonic Foraminifera
Photosymbiosis is one of the key features characterizing planktonic foraminifera; the number of symbiont cells within a single host has been reported to be well over thousands, meaning that photosynthesis by photosymbiosis may be a “hot spot” for primary production, especially in oligotrophic oceans...
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Online Access: | http://dx.doi.org/10.3389/fmars.2022.803354 https://www.frontiersin.org/articles/10.3389/fmars.2022.803354/full |
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crfrontiers:10.3389/fmars.2022.803354 2024-02-11T10:08:03+01:00 Photosynthetic Carbon Assimilation and Electron Transport Rates in Two Symbiont-Bearing Planktonic Foraminifera Takagi, Haruka Kimoto, Katsunori Fujiki, Tetsuichi Japan Society for the Promotion of Science 2022 http://dx.doi.org/10.3389/fmars.2022.803354 https://www.frontiersin.org/articles/10.3389/fmars.2022.803354/full unknown Frontiers Media SA https://creativecommons.org/licenses/by/4.0/ Frontiers in Marine Science volume 9 ISSN 2296-7745 Ocean Engineering Water Science and Technology Aquatic Science Global and Planetary Change Oceanography journal-article 2022 crfrontiers https://doi.org/10.3389/fmars.2022.803354 2024-01-26T09:56:08Z Photosymbiosis is one of the key features characterizing planktonic foraminifera; the number of symbiont cells within a single host has been reported to be well over thousands, meaning that photosynthesis by photosymbiosis may be a “hot spot” for primary production, especially in oligotrophic oceans. As microenvironmental conditions around foraminifera are greatly affected by rapid biological activities—such as photosynthesis and respiration—information on the photosynthetic activities of symbionts is essential to interpret the geochemical proxies recorded in foraminiferal tests (e.g., δ 13 C and δ 18 O). Recently, active chlorophyll fluorometry has been increasingly employed as a useful tool for immediate estimation of photosynthesis. However, carbon assimilation rates are the only direct indicator of the photosynthetic carbon flux. Therefore, before utilizing active fluorescence methods to understand carbon dynamics in foraminiferal symbiosis, it is necessary to confirm the relationship between the fluorescence-based photosynthetic rate [electron transport rate ( ETR )] and carbon assimilation rate ( P ). Here, these two rates were compared for two species, Trilobatus sacculifer and Globigerinella siphonifera Type II, using 14 C-tracer experiments and active fluorometric measurements by fast repetition rate fluorometry. The results showed a significant positive correlation between the P and ETR of the two species, indicating that carbon assimilation can be estimated by the fluorometric method. However, the regression slopes, which represent the apparent electron requirement for carbon assimilation (e – /C), were significantly different in the two species, and were estimated at 26.2 for T. sacculifer and 96.5 for G. siphonifera . These are strikingly high, considering the theoretically and empirically realistic e – /C values. We hypothesized that the high e – /C observed may be due in part to the use of unlabeled respiratory carbon (underestimation of P ). A simple mass balance calculation suggests that a ... Article in Journal/Newspaper Planktonic foraminifera Frontiers (Publisher) Frontiers in Marine Science 9 |
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Open Polar |
collection |
Frontiers (Publisher) |
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crfrontiers |
language |
unknown |
topic |
Ocean Engineering Water Science and Technology Aquatic Science Global and Planetary Change Oceanography |
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Ocean Engineering Water Science and Technology Aquatic Science Global and Planetary Change Oceanography Takagi, Haruka Kimoto, Katsunori Fujiki, Tetsuichi Photosynthetic Carbon Assimilation and Electron Transport Rates in Two Symbiont-Bearing Planktonic Foraminifera |
topic_facet |
Ocean Engineering Water Science and Technology Aquatic Science Global and Planetary Change Oceanography |
description |
Photosymbiosis is one of the key features characterizing planktonic foraminifera; the number of symbiont cells within a single host has been reported to be well over thousands, meaning that photosynthesis by photosymbiosis may be a “hot spot” for primary production, especially in oligotrophic oceans. As microenvironmental conditions around foraminifera are greatly affected by rapid biological activities—such as photosynthesis and respiration—information on the photosynthetic activities of symbionts is essential to interpret the geochemical proxies recorded in foraminiferal tests (e.g., δ 13 C and δ 18 O). Recently, active chlorophyll fluorometry has been increasingly employed as a useful tool for immediate estimation of photosynthesis. However, carbon assimilation rates are the only direct indicator of the photosynthetic carbon flux. Therefore, before utilizing active fluorescence methods to understand carbon dynamics in foraminiferal symbiosis, it is necessary to confirm the relationship between the fluorescence-based photosynthetic rate [electron transport rate ( ETR )] and carbon assimilation rate ( P ). Here, these two rates were compared for two species, Trilobatus sacculifer and Globigerinella siphonifera Type II, using 14 C-tracer experiments and active fluorometric measurements by fast repetition rate fluorometry. The results showed a significant positive correlation between the P and ETR of the two species, indicating that carbon assimilation can be estimated by the fluorometric method. However, the regression slopes, which represent the apparent electron requirement for carbon assimilation (e – /C), were significantly different in the two species, and were estimated at 26.2 for T. sacculifer and 96.5 for G. siphonifera . These are strikingly high, considering the theoretically and empirically realistic e – /C values. We hypothesized that the high e – /C observed may be due in part to the use of unlabeled respiratory carbon (underestimation of P ). A simple mass balance calculation suggests that a ... |
author2 |
Japan Society for the Promotion of Science |
format |
Article in Journal/Newspaper |
author |
Takagi, Haruka Kimoto, Katsunori Fujiki, Tetsuichi |
author_facet |
Takagi, Haruka Kimoto, Katsunori Fujiki, Tetsuichi |
author_sort |
Takagi, Haruka |
title |
Photosynthetic Carbon Assimilation and Electron Transport Rates in Two Symbiont-Bearing Planktonic Foraminifera |
title_short |
Photosynthetic Carbon Assimilation and Electron Transport Rates in Two Symbiont-Bearing Planktonic Foraminifera |
title_full |
Photosynthetic Carbon Assimilation and Electron Transport Rates in Two Symbiont-Bearing Planktonic Foraminifera |
title_fullStr |
Photosynthetic Carbon Assimilation and Electron Transport Rates in Two Symbiont-Bearing Planktonic Foraminifera |
title_full_unstemmed |
Photosynthetic Carbon Assimilation and Electron Transport Rates in Two Symbiont-Bearing Planktonic Foraminifera |
title_sort |
photosynthetic carbon assimilation and electron transport rates in two symbiont-bearing planktonic foraminifera |
publisher |
Frontiers Media SA |
publishDate |
2022 |
url |
http://dx.doi.org/10.3389/fmars.2022.803354 https://www.frontiersin.org/articles/10.3389/fmars.2022.803354/full |
genre |
Planktonic foraminifera |
genre_facet |
Planktonic foraminifera |
op_source |
Frontiers in Marine Science volume 9 ISSN 2296-7745 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.3389/fmars.2022.803354 |
container_title |
Frontiers in Marine Science |
container_volume |
9 |
_version_ |
1790606989229817856 |