Photosynthetic adaptation to low iron, light, and temperature in Southern Ocean phytoplankton
Phytoplankton productivity in the polar Southern Ocean (SO) plays an important role in the transfer of carbon from the atmosphere to the ocean’s interior, a process called the biological carbon pump, which helps regulate global climate. SO productivity in turn is limited by low iron, light, and temp...
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ftpubmed:oai:pubmedcentral.nih.gov:6410794 2023-05-15T18:25:07+02:00 Photosynthetic adaptation to low iron, light, and temperature in Southern Ocean phytoplankton Strzepek, Robert F. Boyd, Philip W. Sunda, William G. 2019-03-05 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6410794/ http://www.ncbi.nlm.nih.gov/pubmed/30787187 https://doi.org/10.1073/pnas.1810886116 en eng National Academy of Sciences http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6410794/ http://www.ncbi.nlm.nih.gov/pubmed/30787187 http://dx.doi.org/10.1073/pnas.1810886116 Published under the PNAS license (https://www.pnas.org/site/aboutpnas/licenses.xhtml) . Biological Sciences Text 2019 ftpubmed https://doi.org/10.1073/pnas.1810886116 2019-09-08T00:23:28Z Phytoplankton productivity in the polar Southern Ocean (SO) plays an important role in the transfer of carbon from the atmosphere to the ocean’s interior, a process called the biological carbon pump, which helps regulate global climate. SO productivity in turn is limited by low iron, light, and temperature, which restrict the efficiency of the carbon pump. Iron and light can colimit productivity due to the high iron content of the photosynthetic photosystems and the need for increased photosystems for low-light acclimation in many phytoplankton. Here we show that SO phytoplankton have evolved critical adaptations to enhance photosynthetic rates under the joint constraints of low iron, light, and temperature. Under growth-limiting iron and light levels, three SO species had up to sixfold higher photosynthetic rates per photosystem II and similar or higher rates per mol of photosynthetic iron than temperate species, despite their lower growth temperature (3 vs. 18 °C) and light intensity (30 vs. 40 μmol quanta⋅m(2)⋅s(−1)), which should have decreased photosynthetic rates. These unexpectedly high rates in the SO species are partly explained by their unusually large photosynthetic antennae, which are among the largest ever recorded in marine phytoplankton. Large antennae are disadvantageous at low light intensities because they increase excitation energy loss as heat, but this loss may be mitigated by the low SO temperatures. Such adaptations point to higher SO production rates than environmental conditions should otherwise permit, with implications for regional ecology and biogeochemistry. Text Southern Ocean PubMed Central (PMC) Southern Ocean Proceedings of the National Academy of Sciences 116 10 4388 4393 |
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Biological Sciences |
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Biological Sciences Strzepek, Robert F. Boyd, Philip W. Sunda, William G. Photosynthetic adaptation to low iron, light, and temperature in Southern Ocean phytoplankton |
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Biological Sciences |
description |
Phytoplankton productivity in the polar Southern Ocean (SO) plays an important role in the transfer of carbon from the atmosphere to the ocean’s interior, a process called the biological carbon pump, which helps regulate global climate. SO productivity in turn is limited by low iron, light, and temperature, which restrict the efficiency of the carbon pump. Iron and light can colimit productivity due to the high iron content of the photosynthetic photosystems and the need for increased photosystems for low-light acclimation in many phytoplankton. Here we show that SO phytoplankton have evolved critical adaptations to enhance photosynthetic rates under the joint constraints of low iron, light, and temperature. Under growth-limiting iron and light levels, three SO species had up to sixfold higher photosynthetic rates per photosystem II and similar or higher rates per mol of photosynthetic iron than temperate species, despite their lower growth temperature (3 vs. 18 °C) and light intensity (30 vs. 40 μmol quanta⋅m(2)⋅s(−1)), which should have decreased photosynthetic rates. These unexpectedly high rates in the SO species are partly explained by their unusually large photosynthetic antennae, which are among the largest ever recorded in marine phytoplankton. Large antennae are disadvantageous at low light intensities because they increase excitation energy loss as heat, but this loss may be mitigated by the low SO temperatures. Such adaptations point to higher SO production rates than environmental conditions should otherwise permit, with implications for regional ecology and biogeochemistry. |
format |
Text |
author |
Strzepek, Robert F. Boyd, Philip W. Sunda, William G. |
author_facet |
Strzepek, Robert F. Boyd, Philip W. Sunda, William G. |
author_sort |
Strzepek, Robert F. |
title |
Photosynthetic adaptation to low iron, light, and temperature in Southern Ocean phytoplankton |
title_short |
Photosynthetic adaptation to low iron, light, and temperature in Southern Ocean phytoplankton |
title_full |
Photosynthetic adaptation to low iron, light, and temperature in Southern Ocean phytoplankton |
title_fullStr |
Photosynthetic adaptation to low iron, light, and temperature in Southern Ocean phytoplankton |
title_full_unstemmed |
Photosynthetic adaptation to low iron, light, and temperature in Southern Ocean phytoplankton |
title_sort |
photosynthetic adaptation to low iron, light, and temperature in southern ocean phytoplankton |
publisher |
National Academy of Sciences |
publishDate |
2019 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6410794/ http://www.ncbi.nlm.nih.gov/pubmed/30787187 https://doi.org/10.1073/pnas.1810886116 |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_relation |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6410794/ http://www.ncbi.nlm.nih.gov/pubmed/30787187 http://dx.doi.org/10.1073/pnas.1810886116 |
op_rights |
Published under the PNAS license (https://www.pnas.org/site/aboutpnas/licenses.xhtml) . |
op_doi |
https://doi.org/10.1073/pnas.1810886116 |
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Proceedings of the National Academy of Sciences |
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116 |
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10 |
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4388 |
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4393 |
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1766206347902189568 |