Diapycnal mixing across the photic zone of the NE Atlantic
Variable physical conditions such as vertical turbulent exchange, internal wave, and mesoscale eddy action affect the availability of light and nutrients for phytoplankton (unicellular algae) growth. It is hypothesized that changes in ocean temperature may affect ocean vertical density stratificatio...
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ftcopernicus:oai:publications.copernicus.org:os87118 2023-05-15T17:41:32+02:00 Diapycnal mixing across the photic zone of the NE Atlantic Haren, Hans Brussaard, Corina P. D. Gerringa, Loes J. A. Manen, Mathijs H. Middag, Rob Groenewegen, Ruud 2021-02-17 application/pdf https://doi.org/10.5194/os-17-301-2021 https://os.copernicus.org/articles/17/301/2021/ eng eng doi:10.5194/os-17-301-2021 https://os.copernicus.org/articles/17/301/2021/ eISSN: 1812-0792 Text 2021 ftcopernicus https://doi.org/10.5194/os-17-301-2021 2021-02-22T17:22:14Z Variable physical conditions such as vertical turbulent exchange, internal wave, and mesoscale eddy action affect the availability of light and nutrients for phytoplankton (unicellular algae) growth. It is hypothesized that changes in ocean temperature may affect ocean vertical density stratification, which may hamper vertical exchange. In order to quantify variations in physical conditions in the northeast Atlantic Ocean, we sampled a latitudinal transect along 17 ± 5 ∘ W between 30 and 63 ∘ N in summer. A shipborne conductivity–temperature–depth (CTD) instrumented package was used with a custom-made modification of the pump inlet to minimize detrimental effects of ship motions on its data. Thorpe-scale analysis was used to establish turbulence values for the upper 500 m from three to six profiles obtained in a short CTD yo-yo, 3 to 5 h after local sunrise. From south to north, average temperature decreased together with stratification while turbulence values weakly increased or remained constant. Vertical turbulent nutrient fluxes did not vary significantly with stratification and latitude. This apparent lack of correspondence between turbulent mixing and temperature is likely due to internal waves breaking (increased stratification can support more internal waves), acting as a potential feedback mechanism. As this feedback mechanism mediates potential physical environment changes in temperature, global surface ocean warming may not affect the vertical nutrient fluxes to a large degree. We urge modellers to test this deduction as it could imply that the future summer phytoplankton productivity in stratified oligotrophic waters would experience little alterations in nutrient input from deeper waters. Text Northeast Atlantic Copernicus Publications: E-Journals Ocean Science 17 1 301 318 |
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Open Polar |
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Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
Variable physical conditions such as vertical turbulent exchange, internal wave, and mesoscale eddy action affect the availability of light and nutrients for phytoplankton (unicellular algae) growth. It is hypothesized that changes in ocean temperature may affect ocean vertical density stratification, which may hamper vertical exchange. In order to quantify variations in physical conditions in the northeast Atlantic Ocean, we sampled a latitudinal transect along 17 ± 5 ∘ W between 30 and 63 ∘ N in summer. A shipborne conductivity–temperature–depth (CTD) instrumented package was used with a custom-made modification of the pump inlet to minimize detrimental effects of ship motions on its data. Thorpe-scale analysis was used to establish turbulence values for the upper 500 m from three to six profiles obtained in a short CTD yo-yo, 3 to 5 h after local sunrise. From south to north, average temperature decreased together with stratification while turbulence values weakly increased or remained constant. Vertical turbulent nutrient fluxes did not vary significantly with stratification and latitude. This apparent lack of correspondence between turbulent mixing and temperature is likely due to internal waves breaking (increased stratification can support more internal waves), acting as a potential feedback mechanism. As this feedback mechanism mediates potential physical environment changes in temperature, global surface ocean warming may not affect the vertical nutrient fluxes to a large degree. We urge modellers to test this deduction as it could imply that the future summer phytoplankton productivity in stratified oligotrophic waters would experience little alterations in nutrient input from deeper waters. |
format |
Text |
author |
Haren, Hans Brussaard, Corina P. D. Gerringa, Loes J. A. Manen, Mathijs H. Middag, Rob Groenewegen, Ruud |
spellingShingle |
Haren, Hans Brussaard, Corina P. D. Gerringa, Loes J. A. Manen, Mathijs H. Middag, Rob Groenewegen, Ruud Diapycnal mixing across the photic zone of the NE Atlantic |
author_facet |
Haren, Hans Brussaard, Corina P. D. Gerringa, Loes J. A. Manen, Mathijs H. Middag, Rob Groenewegen, Ruud |
author_sort |
Haren, Hans |
title |
Diapycnal mixing across the photic zone of the NE Atlantic |
title_short |
Diapycnal mixing across the photic zone of the NE Atlantic |
title_full |
Diapycnal mixing across the photic zone of the NE Atlantic |
title_fullStr |
Diapycnal mixing across the photic zone of the NE Atlantic |
title_full_unstemmed |
Diapycnal mixing across the photic zone of the NE Atlantic |
title_sort |
diapycnal mixing across the photic zone of the ne atlantic |
publishDate |
2021 |
url |
https://doi.org/10.5194/os-17-301-2021 https://os.copernicus.org/articles/17/301/2021/ |
genre |
Northeast Atlantic |
genre_facet |
Northeast Atlantic |
op_source |
eISSN: 1812-0792 |
op_relation |
doi:10.5194/os-17-301-2021 https://os.copernicus.org/articles/17/301/2021/ |
op_doi |
https://doi.org/10.5194/os-17-301-2021 |
container_title |
Ocean Science |
container_volume |
17 |
container_issue |
1 |
container_start_page |
301 |
op_container_end_page |
318 |
_version_ |
1766143134953111552 |