Trends and decadal oscillations of oxygen and nutrients at 50 to 300 m depth in the equatorial and North Pacific
<p>A strong oxygen-deficient layer is located in the upper layers of the tropical Pacific Ocean and deeper in the North Pacific. Processes related to climate change (upper-ocean warming, reduced ventilation) are expected to change ocean oxygen and nutrient inventories. In most ocean basins, a...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2020-02-01
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| Series: | Biogeosciences |
| Online Access: | https://www.biogeosciences.net/17/813/2020/bg-17-813-2020.pdf |
| _version_ | 1819181815631446016 |
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| author | L. Stramma S. Schmidtko S. J. Bograd T. Ono T. Ross D. Sasano F. A. Whitney |
| author_facet | L. Stramma S. Schmidtko S. J. Bograd T. Ono T. Ross D. Sasano F. A. Whitney |
| author_sort | L. Stramma |
| collection | DOAJ |
| description | <p>A strong oxygen-deficient layer is located in the upper
layers of the tropical Pacific Ocean and deeper in the North Pacific.
Processes related to climate change (upper-ocean warming, reduced
ventilation) are expected to change ocean oxygen and nutrient inventories.
In most ocean basins, a decrease in oxygen (“deoxygenation”) and an increase
in nutrients have been observed in subsurface layers. Deoxygenation trends
are not linear and there could be multiple influences on oxygen and nutrient
trends and variability. Here oxygen and nutrient time series since 1950 in
the Pacific Ocean were investigated at 50 to 300 m depth, as this layer
provides critical pelagic habitat for biological communities. In addition to
trends related to ocean warming the oxygen and nutrient trends show a strong
influence of the Pacific Decadal Oscillation (PDO) in the tropical and the
eastern Pacific, and the North Pacific Gyre Oscillation (NPGO) in particular in
the North Pacific. In the Oyashio Region the PDO, the NPGO, the North
Pacific Index (NPI) and an 18.6-year nodal tidal cycle overlay the long-term
trend. In most eastern Pacific regions oxygen increases and nutrients
decrease in the 50 to 300 m layer during the negative PDO phase, with
opposite trends during the positive PDO phase. The PDO index encapsulates
the major mode of sea surface temperature variability in the Pacific, and
oxygen and nutrients trends throughout the basin can be described in the
context of the PDO phases. El Niño and La Niña years often influence
the oxygen and nutrient distribution during the event in the eastern
tropical Pacific but do not have a multi-year influence on the trends.</p> |
| first_indexed | 2024-12-22T22:36:11Z |
| format | Article |
| id | doaj.art-c2d6690d933f46c2838745d279d90bd0 |
| institution | Directory Open Access Journal |
| issn | 1726-4170 1726-4189 |
| language | English |
| last_indexed | 2024-12-22T22:36:11Z |
| publishDate | 2020-02-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Biogeosciences |
| spelling | doaj.art-c2d6690d933f46c2838745d279d90bd02022-12-21T18:10:18ZengCopernicus PublicationsBiogeosciences1726-41701726-41892020-02-011781383110.5194/bg-17-813-2020Trends and decadal oscillations of oxygen and nutrients at 50 to 300 m depth in the equatorial and North PacificL. Stramma0S. Schmidtko1S. J. Bograd2T. Ono3T. Ross4D. Sasano5F. A. Whitney6Research unit “Physical Oceanography”, GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, GermanyResearch unit “Physical Oceanography”, GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, GermanyEnvironmental Research Division, Southwest Fisheries Science Center, NOAA, Monterey, California, USANational Research Institute for Far Sea Fisheries, Fisheries Research and Education Agency, 2-12-4 Fukuura, Kanazawa-Ku, Yokohama 236-8648, JapanInstitute of Ocean Sciences, Fisheries and Oceans Canada, PO Box 6000, Sidney BC V8L 4B2, CanadaGlobal Environment and Marine Department, Japan Meteorological Agency, Tokyo, JapanInstitute of Ocean Sciences, Fisheries and Oceans Canada, PO Box 6000, Sidney BC V8L 4B2, Canada<p>A strong oxygen-deficient layer is located in the upper layers of the tropical Pacific Ocean and deeper in the North Pacific. Processes related to climate change (upper-ocean warming, reduced ventilation) are expected to change ocean oxygen and nutrient inventories. In most ocean basins, a decrease in oxygen (“deoxygenation”) and an increase in nutrients have been observed in subsurface layers. Deoxygenation trends are not linear and there could be multiple influences on oxygen and nutrient trends and variability. Here oxygen and nutrient time series since 1950 in the Pacific Ocean were investigated at 50 to 300 m depth, as this layer provides critical pelagic habitat for biological communities. In addition to trends related to ocean warming the oxygen and nutrient trends show a strong influence of the Pacific Decadal Oscillation (PDO) in the tropical and the eastern Pacific, and the North Pacific Gyre Oscillation (NPGO) in particular in the North Pacific. In the Oyashio Region the PDO, the NPGO, the North Pacific Index (NPI) and an 18.6-year nodal tidal cycle overlay the long-term trend. In most eastern Pacific regions oxygen increases and nutrients decrease in the 50 to 300 m layer during the negative PDO phase, with opposite trends during the positive PDO phase. The PDO index encapsulates the major mode of sea surface temperature variability in the Pacific, and oxygen and nutrients trends throughout the basin can be described in the context of the PDO phases. El Niño and La Niña years often influence the oxygen and nutrient distribution during the event in the eastern tropical Pacific but do not have a multi-year influence on the trends.</p>https://www.biogeosciences.net/17/813/2020/bg-17-813-2020.pdf |
| spellingShingle | L. Stramma S. Schmidtko S. J. Bograd T. Ono T. Ross D. Sasano F. A. Whitney Trends and decadal oscillations of oxygen and nutrients at 50 to 300 m depth in the equatorial and North Pacific Biogeosciences |
| title | Trends and decadal oscillations of oxygen and nutrients at 50 to 300 m depth in the equatorial and North Pacific |
| title_full | Trends and decadal oscillations of oxygen and nutrients at 50 to 300 m depth in the equatorial and North Pacific |
| title_fullStr | Trends and decadal oscillations of oxygen and nutrients at 50 to 300 m depth in the equatorial and North Pacific |
| title_full_unstemmed | Trends and decadal oscillations of oxygen and nutrients at 50 to 300 m depth in the equatorial and North Pacific |
| title_short | Trends and decadal oscillations of oxygen and nutrients at 50 to 300 m depth in the equatorial and North Pacific |
| title_sort | trends and decadal oscillations of oxygen and nutrients at 50 to 300 thinsp m depth in the equatorial and north pacific |
| url | https://www.biogeosciences.net/17/813/2020/bg-17-813-2020.pdf |
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