TY - JOUR
T1 - Mesoscale Variability in the Boundaries of the Oxygen Minimum Zone in the Eastern South Pacific
T2 - Influence of Intrathermocline Eddies
AU - Auger, P. A.
AU - Bento, J. P.
AU - HORMAZABAL FRITZ, SAMUEL ERNESTO
AU - Morales, C. E.
AU - Bustamante, A.
N1 - Funding Information:
The authors wish to thank the International World Ocean Database and Argo projects and the national programs that contribute to it, as these projects collected and made freely available the set of in situ profiles used in this work. Thanks also to O. Ulloa and O. Pizarro for providing data from Argo floats deployed off Chile with the support of the Agouron Institute (Grant AI‐MME1.05), to Cesar Hormazábal, Manuel Castillo, and Luis Pizarro for their help with float deployment and to Winston Rojas, Ricardo De Pol‐Holz and Salvador Ramírez for data acquisition and processing. Satellite altimetry data were produced by Ssalto/Duacs and distributed by AVISO. The authors are most grateful to Luis Valencia, and two anonymous reviewers for their valuable comments on the results of this study. This research was partially supported by the supercomputing infrastructure of the NLHPC (ECM‐02). We also acknowledge the computing time on the Oceano High‐Performance Computing Cluster at PUCV, Chile (FONDEQUIP EQM170214). The present work was supported by the Instituto Milenio de Oceanografía (IMO‐Chile) and funded by the Iniciativa Científica Milenio (ICM‐Chile, ICN12‐019), FONDECYT Project 1151299 (C. E. Morales and S. Hormazabal), FONDECYT 1171895 (S. Hormazabal, C. E. Morales, P. A. Auger and J. P. Bento), and FONDECYT 11160801 (P. A. Auger).
Publisher Copyright:
© 2020. American Geophysical Union. All Rights Reserved.
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2021/2
Y1 - 2021/2
N2 - The vertical variability in the oxygen minimum zone (OMZ) in the eastern South Pacific (ESP; 0–40°S) is characterized by the influence of anticyclonic intrathermocline eddies (ITEs), which are subsurface-intensified mesoscale features that are frequently generated in the coastal upwelling zone off Peru and Chile. The unique lens-shaped signatures that ITEs leave on temperature, salinity, and dissolved oxygen vertical distributions are used as proxies to assess their influences on vertical OMZ boundaries and thickness. Data from in situ profiles in the region (World Ocean Database and Argo databases) are used in correlation analyses between anomalous depths (and vertical displacements) of oxyclines and isopycnals/isotherms, together with an objective eddy detection method based on satellite altimetry to identify the location of such profiles (i.e., outside or inside cyclonic and anticyclonic eddies). The results indicate that most of the vertical fluctuations in the climatological OMZ have a lens-shaped signature and that those at the mesoscale are largely due to ITEs. ITEs are a main driver of the upper oxycline variability in the coastal band, the coastal transition zone (CTZ, 3–10° from the coast) and beyond at mid-latitudes (12–26°S). The influence of ITEs on the upper and lower oxycline variability is mostly observed within the horizontal (offshore) climatological boundary of the OMZ, suggesting that ITEs play a role in the OMZ offshore extension in the ESP. ITEs may produce mesoscale variations in the thickness of the surface-oxygenated layer, resulting in potential changes in prey-predator interactions and in food web functioning.
AB - The vertical variability in the oxygen minimum zone (OMZ) in the eastern South Pacific (ESP; 0–40°S) is characterized by the influence of anticyclonic intrathermocline eddies (ITEs), which are subsurface-intensified mesoscale features that are frequently generated in the coastal upwelling zone off Peru and Chile. The unique lens-shaped signatures that ITEs leave on temperature, salinity, and dissolved oxygen vertical distributions are used as proxies to assess their influences on vertical OMZ boundaries and thickness. Data from in situ profiles in the region (World Ocean Database and Argo databases) are used in correlation analyses between anomalous depths (and vertical displacements) of oxyclines and isopycnals/isotherms, together with an objective eddy detection method based on satellite altimetry to identify the location of such profiles (i.e., outside or inside cyclonic and anticyclonic eddies). The results indicate that most of the vertical fluctuations in the climatological OMZ have a lens-shaped signature and that those at the mesoscale are largely due to ITEs. ITEs are a main driver of the upper oxycline variability in the coastal band, the coastal transition zone (CTZ, 3–10° from the coast) and beyond at mid-latitudes (12–26°S). The influence of ITEs on the upper and lower oxycline variability is mostly observed within the horizontal (offshore) climatological boundary of the OMZ, suggesting that ITEs play a role in the OMZ offshore extension in the ESP. ITEs may produce mesoscale variations in the thickness of the surface-oxygenated layer, resulting in potential changes in prey-predator interactions and in food web functioning.
KW - Argo floats
KW - CTD-O profiles
KW - fish habitat
KW - OMZ
KW - oxycline depth
KW - subsurface eddy
UR - http://www.scopus.com/inward/record.url?scp=85101776928&partnerID=8YFLogxK
U2 - 10.1029/2019JC015272
DO - 10.1029/2019JC015272
M3 - Article
AN - SCOPUS:85101776928
VL - 126
JO - Journal of Geophysical Research: Oceans
JF - Journal of Geophysical Research: Oceans
SN - 2169-9275
IS - 2
M1 - e2019JC015272
ER -