The formation of a subsurface anticyclonic eddy in the Peru-Chile Undercurrent and its impact on the near-coastal salinity, oxygen and nutrient distributions

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Main Authors: Thomsen, Soeren, Kanzow, Torsten, Krahmann, Gerd, Greatbatch, Richard J, Dengler, Marcus
Format: Dataset Open Access
Language:en
Published: PANGAEA 2016
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author Thomsen, Soeren
Kanzow, Torsten
Krahmann, Gerd
Greatbatch, Richard J
Dengler, Marcus
author_facet Thomsen, Soeren
Kanzow, Torsten
Krahmann, Gerd
Greatbatch, Richard J
Dengler, Marcus
collection Datos científicos de ciencias marinas y ambientales
contents The formation of a subsurface anticyclonic eddy in the Peru-Chile Undercurrent (PCUC) in January and February 2013 is investigated using a multi-platform four-dimensional observational approach. Research vessel, multiple glider and mooring-based measurements were conducted in the Peruvian upwelling regime near 12°30'S. The dataset consists of more than 10000 glider profiles and repeated vessel-based hydrography and velocity transects. It allows a detailed description of the eddy formation and its impact on the near-coastal salinity, oxygen and nutrient distributions. In early January, a strong PCUC with maximum poleward velocities of ca. 0.25 m/s at 100 to 200 m depth was observed. Starting on January 20 a subsurface anticyclonic eddy developed in the PCUC downstream of a topographic bend, suggesting flow separation as the eddy formation mechanism. The eddy core waters exhibited oxygen concentrations less than 1mol/kg, an elevated nitrogen-deficit of ca. 17µmol/l and potential vorticity close to zero, which seemed to originate from the bottom boundary layer of the continental slope. The eddy-induced across-shelf velocities resulted in an elevated exchange of water masses between the upper continental slope and the open ocean. Small scale salinity and oxygen structures were formed by along-isopycnal stirring and indications of eddy-driven oxygen ventilation of the upper oxygen minimum zone were observed. It is concluded that mesoscale stirring of solutes and the offshore transport of eddy core properties could provide an important coastal open-ocean exchange mechanism with potentially large implications for nutrient budgets and biogeochemical cycling in the oxygen minimum zone off Peru.
format Dataset Open Access
id pangaea_https___doi_org_10_1594_PANGAEA_860727
institution PANGAEA
language en
publishDate 2016
publisher PANGAEA
record_format pangaea
spellingShingle The formation of a subsurface anticyclonic eddy in the Peru-Chile Undercurrent and its impact on the near-coastal salinity, oxygen and nutrient distributions
Thomsen, Soeren
Kanzow, Torsten
Krahmann, Gerd
Greatbatch, Richard J
Dengler, Marcus
Climate - Biogeochemistry Interactions in the Tropical Ocean; SFB754
The formation of a subsurface anticyclonic eddy in the Peru-Chile Undercurrent (PCUC) in January and February 2013 is investigated using a multi-platform four-dimensional observational approach. Research vessel, multiple glider and mooring-based measurements were conducted in the Peruvian upwelling regime near 12°30'S. The dataset consists of more than 10000 glider profiles and repeated vessel-based hydrography and velocity transects. It allows a detailed description of the eddy formation and its impact on the near-coastal salinity, oxygen and nutrient distributions. In early January, a strong PCUC with maximum poleward velocities of ca. 0.25 m/s at 100 to 200 m depth was observed. Starting on January 20 a subsurface anticyclonic eddy developed in the PCUC downstream of a topographic bend, suggesting flow separation as the eddy formation mechanism. The eddy core waters exhibited oxygen concentrations less than 1mol/kg, an elevated nitrogen-deficit of ca. 17µmol/l and potential vorticity close to zero, which seemed to originate from the bottom boundary layer of the continental slope. The eddy-induced across-shelf velocities resulted in an elevated exchange of water masses between the upper continental slope and the open ocean. Small scale salinity and oxygen structures were formed by along-isopycnal stirring and indications of eddy-driven oxygen ventilation of the upper oxygen minimum zone were observed. It is concluded that mesoscale stirring of solutes and the offshore transport of eddy core properties could provide an important coastal open-ocean exchange mechanism with potentially large implications for nutrient budgets and biogeochemical cycling in the oxygen minimum zone off Peru.
title The formation of a subsurface anticyclonic eddy in the Peru-Chile Undercurrent and its impact on the near-coastal salinity, oxygen and nutrient distributions
topic Climate - Biogeochemistry Interactions in the Tropical Ocean; SFB754
url https://doi.org/10.1594/PANGAEA.860727