Climatic changes in North Atlantic O2 amplified by temperature sensitivity of phytoplankton growth
Ocean warming is associated with a decline in the global oxygen (O-2) inventory, but the ratio of O-2 loss to heat gain is poorly understood. We analyzed historical variability in temperature (T), O-2, and nitrate (NO3- ) in hydrographic observations and model simulations of the North Atlantic, a re...
Published in: | Global Biogeochemical Cycles |
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Language: | English |
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Online Access: | https://doi.org/10.1029/2023GB007930 |
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ftncar:oai:drupal-site.org:articles_26889 2024-04-14T08:15:37+00:00 Climatic changes in North Atlantic O2 amplified by temperature sensitivity of phytoplankton growth Margolskee, A. (author) Ito, T. (author) Long, Matthew (author) Deutsch, C. (author) 2023-12 https://doi.org/10.1029/2023GB007930 en eng Global Biogeochemical Cycles--Global Biogeochemical Cycles--0886-6236--1944-9224 Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) Float Data Archive--10.6075/J0TX3C9X articles:26889 doi:10.1029/2023GB007930 ark:/85065/d7zc870j Copyright author(s). This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. article Text 2023 ftncar https://doi.org/10.1029/2023GB007930 2024-03-21T18:00:26Z Ocean warming is associated with a decline in the global oxygen (O-2) inventory, but the ratio of O-2 loss to heat gain is poorly understood. We analyzed historical variability in temperature (T), O-2, and nitrate (NO3- ) in hydrographic observations and model simulations of the North Atlantic, a relatively well-sampled region that is important for deep ocean ventilation. Multidecadal fluctuations of O-2 concentrations in subpolar thermocline waters (100-700 m) are correlated with changes in their heat content, with a slope 35% steeper than that expected from thermal solubility. Variations of O-2 in excess of the solubility effect are correlated with observed decadal changes in NO3- in the surface layer (0-50 m), which declines by similar to 1 mmol N m(-3) per degree of temperature anomaly. Enhanced biologically mediated drawdown of nutrients from the photic zone and associated respiration in deeper water account for the additional depletion of thermocline O-2 during warm years. In model simulations, increased nutrient consumption in warm periods is driven by an early start of the phytoplankton growing season and faster phytoplankton growth rates at higher temperatures. Our results highlight a role for phytoplankton T-dependent growth rates in amplifying ocean O-2 loss. 1852977 Article in Journal/Newspaper North Atlantic OpenSky (NCAR/UCAR - National Center for Atmospheric Research/University Corporation for Atmospheric Research) Global Biogeochemical Cycles 37 12 |
institution |
Open Polar |
collection |
OpenSky (NCAR/UCAR - National Center for Atmospheric Research/University Corporation for Atmospheric Research) |
op_collection_id |
ftncar |
language |
English |
description |
Ocean warming is associated with a decline in the global oxygen (O-2) inventory, but the ratio of O-2 loss to heat gain is poorly understood. We analyzed historical variability in temperature (T), O-2, and nitrate (NO3- ) in hydrographic observations and model simulations of the North Atlantic, a relatively well-sampled region that is important for deep ocean ventilation. Multidecadal fluctuations of O-2 concentrations in subpolar thermocline waters (100-700 m) are correlated with changes in their heat content, with a slope 35% steeper than that expected from thermal solubility. Variations of O-2 in excess of the solubility effect are correlated with observed decadal changes in NO3- in the surface layer (0-50 m), which declines by similar to 1 mmol N m(-3) per degree of temperature anomaly. Enhanced biologically mediated drawdown of nutrients from the photic zone and associated respiration in deeper water account for the additional depletion of thermocline O-2 during warm years. In model simulations, increased nutrient consumption in warm periods is driven by an early start of the phytoplankton growing season and faster phytoplankton growth rates at higher temperatures. Our results highlight a role for phytoplankton T-dependent growth rates in amplifying ocean O-2 loss. 1852977 |
author2 |
Margolskee, A. (author) Ito, T. (author) Long, Matthew (author) Deutsch, C. (author) |
format |
Article in Journal/Newspaper |
title |
Climatic changes in North Atlantic O2 amplified by temperature sensitivity of phytoplankton growth |
spellingShingle |
Climatic changes in North Atlantic O2 amplified by temperature sensitivity of phytoplankton growth |
title_short |
Climatic changes in North Atlantic O2 amplified by temperature sensitivity of phytoplankton growth |
title_full |
Climatic changes in North Atlantic O2 amplified by temperature sensitivity of phytoplankton growth |
title_fullStr |
Climatic changes in North Atlantic O2 amplified by temperature sensitivity of phytoplankton growth |
title_full_unstemmed |
Climatic changes in North Atlantic O2 amplified by temperature sensitivity of phytoplankton growth |
title_sort |
climatic changes in north atlantic o2 amplified by temperature sensitivity of phytoplankton growth |
publishDate |
2023 |
url |
https://doi.org/10.1029/2023GB007930 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
Global Biogeochemical Cycles--Global Biogeochemical Cycles--0886-6236--1944-9224 Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) Float Data Archive--10.6075/J0TX3C9X articles:26889 doi:10.1029/2023GB007930 ark:/85065/d7zc870j |
op_rights |
Copyright author(s). This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. |
op_doi |
https://doi.org/10.1029/2023GB007930 |
container_title |
Global Biogeochemical Cycles |
container_volume |
37 |
container_issue |
12 |
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1796314011890876416 |