Global distribution and variability of subsurface chlorophyll a concentrations
Chlorophyll a (Chl a) often exhibits a maximum concentration in the subsurface layer rather that at the surface. The depth of the Chl a maximum primarily depends on the balance between light penetration from the surface and the nutrient supply from the deep ocean. However, a global map of subsurface...
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Copernicus Gesellschaft Mbh
2022
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ftarchimer:oai:archimer.ifremer.fr:86710 2023-05-15T18:25:52+02:00 Global distribution and variability of subsurface chlorophyll a concentrations Yasunaka, Sayaka Ono, Tsuneo Sasaoka, Kosei Sato, Kanako 2022-02 application/pdf https://archimer.ifremer.fr/doc/00755/86710/92202.pdf https://archimer.ifremer.fr/doc/00755/86710/92203.pdf https://archimer.ifremer.fr/doc/00755/86710/92204.pdf https://archimer.ifremer.fr/doc/00755/86710/92205.pdf https://doi.org/10.5194/os-18-255-2022 https://archimer.ifremer.fr/doc/00755/86710/ eng eng Copernicus Gesellschaft Mbh https://archimer.ifremer.fr/doc/00755/86710/92202.pdf https://archimer.ifremer.fr/doc/00755/86710/92203.pdf https://archimer.ifremer.fr/doc/00755/86710/92204.pdf https://archimer.ifremer.fr/doc/00755/86710/92205.pdf doi:10.5194/os-18-255-2022 https://archimer.ifremer.fr/doc/00755/86710/ info:eu-repo/semantics/openAccess restricted use Ocean Science (1812-0784) (Copernicus Gesellschaft Mbh), 2022-02 , Vol. 18 , N. 1 , P. 255-268 text Publication info:eu-repo/semantics/article 2022 ftarchimer https://doi.org/10.5194/os-18-255-2022 2022-03-15T23:50:01Z Chlorophyll a (Chl a) often exhibits a maximum concentration in the subsurface layer rather that at the surface. The depth of the Chl a maximum primarily depends on the balance between light penetration from the surface and the nutrient supply from the deep ocean. However, a global map of subsurface Chl a concentrations based on observations has not been presented yet. In this study, we integrate Chl a concentration data from recent biogeochemical floats and historical ship-based (and other) observations and present global maps of subsurface Chl a concentrations with related variables. The subsurface Chl a maximum was observed globally throughout the oceans: at depths greater than 80m in the subtropics and tropics (30 degrees S to 30 degrees N); in the 40-80m depth range in the tropics, in the Southern Ocean (south of 40 degrees S), and at the midlatitudes (30-40 degrees N/S) in the North Pacific; and at depths of less than 40m in the northern subarctic (north of 40 degrees N). The observed maxima all lie below the mixed-layer depth for the entire year in the subtropics and tropics and during summer in the midlatitudes and the northern subarctic. The depths of the subsurface Chl a maxima are greater than those of the photosynthetically active layer in the subtropics but shallower in the tropics and midlatitudes. In the subtropics, a seasonal increase in oxygen below the mixed layer implies substantial new biological production, which corresponds to 10% of the net primary production in that region. During El Nino, subsurface Chl a concentrations are higher in the middle and eastern equatorial Pacific but lower to the west in comparison with La Nina, a pattern which is opposite to that on the surface. The spatiotemporal variability of the Chl a concentrations described here has implications to not only for the biogeochemical cycling in the ocean but also for understanding the thermal structure and dynamics of the ocean via absorption of shortwave radiation. Article in Journal/Newspaper Southern Ocean Subarctic Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) Southern Ocean Pacific Ocean Science 18 1 255 268 |
institution |
Open Polar |
collection |
Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) |
op_collection_id |
ftarchimer |
language |
English |
description |
Chlorophyll a (Chl a) often exhibits a maximum concentration in the subsurface layer rather that at the surface. The depth of the Chl a maximum primarily depends on the balance between light penetration from the surface and the nutrient supply from the deep ocean. However, a global map of subsurface Chl a concentrations based on observations has not been presented yet. In this study, we integrate Chl a concentration data from recent biogeochemical floats and historical ship-based (and other) observations and present global maps of subsurface Chl a concentrations with related variables. The subsurface Chl a maximum was observed globally throughout the oceans: at depths greater than 80m in the subtropics and tropics (30 degrees S to 30 degrees N); in the 40-80m depth range in the tropics, in the Southern Ocean (south of 40 degrees S), and at the midlatitudes (30-40 degrees N/S) in the North Pacific; and at depths of less than 40m in the northern subarctic (north of 40 degrees N). The observed maxima all lie below the mixed-layer depth for the entire year in the subtropics and tropics and during summer in the midlatitudes and the northern subarctic. The depths of the subsurface Chl a maxima are greater than those of the photosynthetically active layer in the subtropics but shallower in the tropics and midlatitudes. In the subtropics, a seasonal increase in oxygen below the mixed layer implies substantial new biological production, which corresponds to 10% of the net primary production in that region. During El Nino, subsurface Chl a concentrations are higher in the middle and eastern equatorial Pacific but lower to the west in comparison with La Nina, a pattern which is opposite to that on the surface. The spatiotemporal variability of the Chl a concentrations described here has implications to not only for the biogeochemical cycling in the ocean but also for understanding the thermal structure and dynamics of the ocean via absorption of shortwave radiation. |
format |
Article in Journal/Newspaper |
author |
Yasunaka, Sayaka Ono, Tsuneo Sasaoka, Kosei Sato, Kanako |
spellingShingle |
Yasunaka, Sayaka Ono, Tsuneo Sasaoka, Kosei Sato, Kanako Global distribution and variability of subsurface chlorophyll a concentrations |
author_facet |
Yasunaka, Sayaka Ono, Tsuneo Sasaoka, Kosei Sato, Kanako |
author_sort |
Yasunaka, Sayaka |
title |
Global distribution and variability of subsurface chlorophyll a concentrations |
title_short |
Global distribution and variability of subsurface chlorophyll a concentrations |
title_full |
Global distribution and variability of subsurface chlorophyll a concentrations |
title_fullStr |
Global distribution and variability of subsurface chlorophyll a concentrations |
title_full_unstemmed |
Global distribution and variability of subsurface chlorophyll a concentrations |
title_sort |
global distribution and variability of subsurface chlorophyll a concentrations |
publisher |
Copernicus Gesellschaft Mbh |
publishDate |
2022 |
url |
https://archimer.ifremer.fr/doc/00755/86710/92202.pdf https://archimer.ifremer.fr/doc/00755/86710/92203.pdf https://archimer.ifremer.fr/doc/00755/86710/92204.pdf https://archimer.ifremer.fr/doc/00755/86710/92205.pdf https://doi.org/10.5194/os-18-255-2022 https://archimer.ifremer.fr/doc/00755/86710/ |
geographic |
Southern Ocean Pacific |
geographic_facet |
Southern Ocean Pacific |
genre |
Southern Ocean Subarctic |
genre_facet |
Southern Ocean Subarctic |
op_source |
Ocean Science (1812-0784) (Copernicus Gesellschaft Mbh), 2022-02 , Vol. 18 , N. 1 , P. 255-268 |
op_relation |
https://archimer.ifremer.fr/doc/00755/86710/92202.pdf https://archimer.ifremer.fr/doc/00755/86710/92203.pdf https://archimer.ifremer.fr/doc/00755/86710/92204.pdf https://archimer.ifremer.fr/doc/00755/86710/92205.pdf doi:10.5194/os-18-255-2022 https://archimer.ifremer.fr/doc/00755/86710/ |
op_rights |
info:eu-repo/semantics/openAccess restricted use |
op_doi |
https://doi.org/10.5194/os-18-255-2022 |
container_title |
Ocean Science |
container_volume |
18 |
container_issue |
1 |
container_start_page |
255 |
op_container_end_page |
268 |
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1766207569652613120 |