The Arctic picoeukaryote Micromonas pusilla benefits from ocean acidification under constant and dynamic light

Compared to the rest of the globe, the Arctic Ocean is affected disproportionately by climate change. Despite these fast environmental changes, we currently know little about the effects of ocean acidification (OA) on marine key species in this area. Moreover, the existing studies typically test the...

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Published in:Biogeosciences
Main Authors: White, Emily, Hoppe, Clara J. M., Rost, Björn
Format: Text
Language:English
Published: 2020
Subjects:
Online Access:https://doi.org/10.5194/bg-17-635-2020
https://www.biogeosciences.net/17/635/2020/
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spelling ftcopernicus:oai:publications.copernicus.org:bg79771 2023-05-15T14:51:59+02:00 The Arctic picoeukaryote Micromonas pusilla benefits from ocean acidification under constant and dynamic light White, Emily Hoppe, Clara J. M. Rost, Björn 2020-02-07 application/pdf https://doi.org/10.5194/bg-17-635-2020 https://www.biogeosciences.net/17/635/2020/ eng eng doi:10.5194/bg-17-635-2020 https://www.biogeosciences.net/17/635/2020/ eISSN: 1726-4189 Text 2020 ftcopernicus https://doi.org/10.5194/bg-17-635-2020 2020-02-10T15:42:01Z Compared to the rest of the globe, the Arctic Ocean is affected disproportionately by climate change. Despite these fast environmental changes, we currently know little about the effects of ocean acidification (OA) on marine key species in this area. Moreover, the existing studies typically test the effects of OA under constant, hence artificial, light fields. In this study, the abundant Arctic picoeukaryote Micromonas pusilla was acclimated to current (400 µ atm) and future (1000 µ atm) p CO 2 levels under a constant as well as a dynamic light, simulating more realistic light fields as experienced in the upper mixed layer. To describe and understand the responses to these drivers, growth, particulate organic carbon (POC) production, elemental composition, photophysiology and reactive oxygen species (ROS) production were analysed. M. pusilla was able to benefit from OA on various scales, ranging from an increase in growth rates to enhanced photosynthetic capacity, irrespective of the light regime. These beneficial effects were, however, not reflected in the POC production rates, which can be explained by energy partitioning towards cell division rather than biomass build-up. In the dynamic light regime, M. pusilla was able to optimize its photophysiology for effective light usage during both low- and high-light periods. This photoacclimative response, which was achieved by modifications to photosystem II (PSII), imposed high metabolic costs leading to a reduction in growth and POC production rates when compared to constant light. There were no significant interactions observed between dynamic light and OA, indicating that M. pusilla is able to maintain effective photoacclimation without increased photoinactivation under high p CO 2 . Based on these findings, M. pusilla is likely to cope well with future conditions in the Arctic Ocean. Text Arctic Arctic Ocean Climate change Ocean acidification Copernicus Publications: E-Journals Arctic Arctic Ocean Biogeosciences 17 3 635 647
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collection Copernicus Publications: E-Journals
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language English
description Compared to the rest of the globe, the Arctic Ocean is affected disproportionately by climate change. Despite these fast environmental changes, we currently know little about the effects of ocean acidification (OA) on marine key species in this area. Moreover, the existing studies typically test the effects of OA under constant, hence artificial, light fields. In this study, the abundant Arctic picoeukaryote Micromonas pusilla was acclimated to current (400 µ atm) and future (1000 µ atm) p CO 2 levels under a constant as well as a dynamic light, simulating more realistic light fields as experienced in the upper mixed layer. To describe and understand the responses to these drivers, growth, particulate organic carbon (POC) production, elemental composition, photophysiology and reactive oxygen species (ROS) production were analysed. M. pusilla was able to benefit from OA on various scales, ranging from an increase in growth rates to enhanced photosynthetic capacity, irrespective of the light regime. These beneficial effects were, however, not reflected in the POC production rates, which can be explained by energy partitioning towards cell division rather than biomass build-up. In the dynamic light regime, M. pusilla was able to optimize its photophysiology for effective light usage during both low- and high-light periods. This photoacclimative response, which was achieved by modifications to photosystem II (PSII), imposed high metabolic costs leading to a reduction in growth and POC production rates when compared to constant light. There were no significant interactions observed between dynamic light and OA, indicating that M. pusilla is able to maintain effective photoacclimation without increased photoinactivation under high p CO 2 . Based on these findings, M. pusilla is likely to cope well with future conditions in the Arctic Ocean.
format Text
author White, Emily
Hoppe, Clara J. M.
Rost, Björn
spellingShingle White, Emily
Hoppe, Clara J. M.
Rost, Björn
The Arctic picoeukaryote Micromonas pusilla benefits from ocean acidification under constant and dynamic light
author_facet White, Emily
Hoppe, Clara J. M.
Rost, Björn
author_sort White, Emily
title The Arctic picoeukaryote Micromonas pusilla benefits from ocean acidification under constant and dynamic light
title_short The Arctic picoeukaryote Micromonas pusilla benefits from ocean acidification under constant and dynamic light
title_full The Arctic picoeukaryote Micromonas pusilla benefits from ocean acidification under constant and dynamic light
title_fullStr The Arctic picoeukaryote Micromonas pusilla benefits from ocean acidification under constant and dynamic light
title_full_unstemmed The Arctic picoeukaryote Micromonas pusilla benefits from ocean acidification under constant and dynamic light
title_sort arctic picoeukaryote micromonas pusilla benefits from ocean acidification under constant and dynamic light
publishDate 2020
url https://doi.org/10.5194/bg-17-635-2020
https://www.biogeosciences.net/17/635/2020/
geographic Arctic
Arctic Ocean
geographic_facet Arctic
Arctic Ocean
genre Arctic
Arctic Ocean
Climate change
Ocean acidification
genre_facet Arctic
Arctic Ocean
Climate change
Ocean acidification
op_source eISSN: 1726-4189
op_relation doi:10.5194/bg-17-635-2020
https://www.biogeosciences.net/17/635/2020/
op_doi https://doi.org/10.5194/bg-17-635-2020
container_title Biogeosciences
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