F. Schütte et al.: Hidden vortices: near-equatorial low-oxygen extremes driven by high-baroclinic-mode vortices 141

Dilmahamod, A. F,, Karstensen, J., Dietze, H., Löptien, U., and
Fennel, K.: Generation Mechanisms of Mesoscale Eddies in the
Mauritanian Upwelling Region, J. Phys. Oceanogr., 52, 161-182,
https://doi.org/10.1175/JPO-D-21-0092.1, 2022.
Dufour, C. O., Griffies, S. M., de Souza, G. F., Frenger, I., Morrison,
A. K.,, Palter, J. B., Sarmiento, J. L., Galbraith, E. D., Dunne, J.
P., Anderson, W. G., and Slater, R. D.: Role of Mesoscale Eddies
in Cross-Frontal Transport of Heat and Biogeochemical Tracers
 in the Southern Ocean, J. Phys. Oceanogr., 45, 3057-3081,
https://doi.org/10.1175/jpo-d-14-0240.1, 2015.
Duteil, O., Schwarzkopf, F. U., Böning, C. W., and Oschlies, A.:
Major role of the equatorial current system in setting 0Xygen
 levels in the eastern tropical Atlantic Ocean: A highzesolution
 model study, Geophys. Res. Lett., 41, 2033-2040,
https://doi.org/10.1002/2013g1058888, 2014.
£den, C.: Eddy length scales in the North Atlantic Ocean, J. Geophys.
 Res.-Oceans, 112, https://doi.0org/10.1029/2006jc003901,
2007.
E.U. Copernicus Marine Service Information: Global Ocean Gridded
 L 4 Sea Surface Heights And Derived Variables Reprocessed
 1993 Ongoing, Marine Data Store (MDS) [data set],
https://doi.0rg/10.48670/moi-00148, 2024.
Fiedler, B., Grundle, D. S., Schütte, F., Karstensen, J., Löscher, C.
R., Hauss, H., Wagner, H., Loginova, A., Kiko, R., Silva, P.,
Tanhua, T., and Körtzinger, A.: Oxygen utilization and downward
 carbon flux in an oxygen-depleted eddy in the eastern
 tropical North Atlantic, Biogeosciences, 13, 5633-5647,
https://doi.org/10.5194/bg-13-5633-2016, 2016.
Fischer, J., Brandt, P., Dengler, M., Müller, M., and Symonds,
D.: Surveying the Upper Ocean with the Ocean Surveyor:
A New Phased Array Doppler Current Profiler, J. Atmos.
 Ocean. Tech., 20, 742-751, https:/doi.org/10.1175/1520-0426(2003)20<742:
 Stuowt>2.0.Co;2, 2003.
Frenger, I.: Supplementary model data to: Hidden vortices: Nearequatorial
 lowoxygen extremes driven by high-baroclinic-mode
vortices [data set and code], GEOMAR Helmholtz Centre for
Ocean Research Kiel [distributor], https://hdl.handle.net/20.500.
12085/21ab7868-c112-4173-ada4-75b86f098f18,
Frenger, I., Bianchi, D., Stührenberg, C., Oschlies, A., Dunne,
J., Deutsch, C., Galbraith, E., and Schütte, FE: Biogeochemical
 Role of Subsurface Coherent Eddies in the
Ocean: Tracer Cannonballs, Hypoxic Storms, and Micro-»%al
 Stewpots?, Global Biogeochem. Cy., 32, 226-249,
attps://doi.0org/10.1002/2017GB005743, 2018.
(Galbraith, E. D., Dunne, J. P., Gnanadesikan, A., Slater, R.
D., Sarmiento, J. L., Dufour, C. O., de Souza, G. F,
Bianchi, D., Claret, M., Rodgers, K. B., and Marvasti,
S. S.: Complex functionality with minimal computation:
Promise and pitfalls of reduced-tracer ocean biogeochemistry
 models, J. Adv. Model. Earth Syst., 7, 2012-2028,
https://doi.org/10.1002/2015ms000463, 2015.
Garcia, H. E., Locarnini, R. A., Boyer, T. P., Antonov, J. I., Baranova,
 O. K., Zweng, M. M., and Johnson, D. R.: World Ocean
Atlas 2009, in: Volume 3: Dissolved Oxygen, Apparent Oxygen
Utilization, and Oxygen Saturation, NOAA Atlas NESDIS 70,
edited by: Levitus, S., US Government Printing Office, Washington,
 D.C., 344 pp., https://doi.0org/10.25923/rb67-ns53, 2010a.
Garcia, H. E., Locarnini, R. A., Boyer, T. P., Antonov, J. IL, Zweng,
M. M.. Baranova. O. K.. and Johnson. D. R.: World Ocean Athttps:/doi.org/10.5194/os-22-119-2026



las 2009, in: Volume 4: Nutrients (phosphate, nitrate, silicate),
NOAA Atlas NESDIS 71, edited by: Levitus, S., US Government
 Printing Office, Washington, D.C., 398 pp., http://www.
nodc.noaa.gov/OC5/indprod.html (last access: 15 June 2023).
2010b.
Garcia, H. E., Wang, Z., Bouchard, C., Cross, S. L., Paver, C. R.,
Reagan, J. R., Boyer, T. P., Locarnini, R. A., Mishonov, A. V.,
Baranova, O., Seidov, D., and Dukhovskoy, D.: World Ocean Atlas
 2023, Volume 3: Dissolved Oxygen, Apparent Oxygen Utilization,
 Dissolved Oxygen Saturation and 30 year Climate Normal,
 A. Mishonov, Tech. Ed. NOAA Atlas NESDIS 91 [data set].
https://doi.org/10.25923/rb67-ns53, 2024.
Gill, A. E.: Atmosphere-Ocean Dynamics, in: International Geophysics
 Series Volume 30, Academic Press, New York.
https://doi.org/10.1016/S0074-6142(08)60026-1, 1982.
Griffies, S. M., Winton, M., Anderson, W. G., Benson, R., Delworth,
 T. L., Dufour, C. O., Dunne, J. P., Goddard, P., Morrison,
 A. K., Rosati, A., Wittenberg, A. T., Yin, J., and Zhang,
R.: Impacts on Ocean Heat from Transient Mesoscale Eddies
in a Hierarchy of Climate Models, J. Climate, 28, 952-977,
https://doi.org/10.1175/jcli-d-14-00353.1, 2015.
Gula, J., Blacic, T. M., and Todd, R. E.: Submesoscale Coherent
Vortices in the Gulf Stream, Geophys. Res. Lett., 46, 2704-2714.
https://doi.org/10.1029/2019g108 1919, 2019.
Hahn, J., Brandt, P., Greatbatch, R. J., Krahmann, G., and Kortzinger,
 A.: Oxygen variance and meridional oxygen supply
in the Tropical North East Atlantic oxygen minimum zone,
Clim. Dynam., 43, 2999-3024, https://doi.org/10.1007/s00382-014-2065-0,
 2014.
Hahn, J., Brandt, P., Schmidtko, S., and Krahmann, G.: Decadal
oxygen change in the eastern tropical North Atlantic, Ocean Sci..
13, 551-576, https://doi.org/10.5194/os-13-551-2017, 2017.
Hauss, H., Christiansen, S., Schutte, F., Kiko, R., Lima, M. E., Rodrigues,
 E., Karstensen, J., Loscher, C. R., Kortzinger, A., and
Fiedler, B.: Dead zone or oasis in the open ocean? Zooplankton
 distribution and migration in low-oxygen modewater eddies,
Biogeosciences, 13, 1977-1989, https://doi.org/10.5194/bg-13-1977-2016,
 2016.
Karstensen, J., Stramma, L., and Visbeck, M.: Oxygen
 minimum zones in the eastern tropical Atlantic
and Pacific oceans, Prog. ÖOceanogr., 77, 331-350.
https://doi.org/10.1016/j.pocean.2007.05.009, 2008.
Karstensen, J., Fiedler, B., Schütte, F., Brandt, P., Körtzinger, A.,
Fischer, G., Zantopp, R., Hahn, J., Visbeck, M., and Wallace,
D.: Open ocean dead zones in the tropical North Atlantic Ocean.
Biogeosciences, 12, 2597-2605, https://doi.org/10.5194/bg-12-2597-2015,
 2015.
Karstensen, J., Schütte, F., Pietri, A., Krahmann, G., Fiedler.
B., Grundle, D., Hauss, H., Körtzinger, A., Löscher, C. R.,
Testor, P., Vieira, N., and Visbeck, M.: Upwelling and isolation
 in oxygen-depleted anticyclonic modewater eddies and implications
 for nitrate cycling, Biogeosciences, 14, 2167-2181.
https://doi.org/10.5194/bg-14-2167-2017, 2017.
Keppler, L., Cravatte, S., Chaigneau, A., Pegliasco, C., Gourdeau,
 L., and Singh, A.: Observed Characteristics and Vertical
Structure of Mesoscale Eddies in the Southwest Tropical Pacific,
 Journal of Geophysical Research: Oceans, 123, 2731-2756.
10.1002/2017jc013712, 2018.

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