Meridional and zonal changes in water properties along the continental slope off central and northern Chile

Meridional and zonal changes in water properties along the continental slope off central and northern Chile

The Humboldt-09 cruise covered a narrow meridional band along the Chilean continental slope (44–23º S). Here we use physical and biochemical data from a long meridional section (4000 km) and three short zonal sections (100 km) to describe the distribution of the different water masses found in this...

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Wedi'i Gadw mewn:
Manylion Llyfryddiaeth
Prif Awduron: Llanillo, PJ, Pelegrí, JL, Duarte, CM, Emelianov, M, Gasser, M, Gourrion, J, Rodríguez-Santana, A
Fformat: info:eu-repo/semantics/article
Iaith:eng
Cyhoeddwyd: Iniversidad Autónoma de Baja California 2011
Pynciau:
quasi-extended optimum multiparameter analysis
water masses
oxygen minimum zone
Humboldt Current System
análisis óptimo multiparamétrico cuasi-extendido
zona de mínimo oxígeno
masas de agua
Sistema de la Corriente de Humboldt
Mynediad Ar-lein:https://www.cienciasmarinas.com.mx/index.php/cmarinas/article/view/1814
Tagiau: Ychwanegu Tag
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Crynodeb:The Humboldt-09 cruise covered a narrow meridional band along the Chilean continental slope (44–23º S). Here we use physical and biochemical data from a long meridional section (4000 km) and three short zonal sections (100 km) to describe the distribution of the different water masses found in this region. Six water masses were identified: Subantarctic Water (SAAW), Summer Subantarctic Water (SSAW), Subtropical Water (STW), Equatorial Subsurface Water (ESSW), Antarctic Intermediate Water (AAIW), and Pacific Deep Water (PDW). For the first time, a novel set of source water mass properties (or water types) is introduced for SSAW, and nutrient and dissolved oxygen water types are proposed for all the water masses. Optimum multiparameter (OMP) analysis was used through an iterative process to obtain a sound definition of the water types that minimizes the residuals of the method. Both the classic OMP and the quasi-extended OMP models reproduced the data rather well. Finally, the spatial distribution of the different water masses was calculated with the quasi-extended OMP, which is not influenced by the respiration of organic matter. The distribution of the different water masses is presented over the meridional and zonal transects and in property-property diagrams. A smooth meridional transition from subantarctic to tropical and equatorial water masses is observed in this area. This transition takes place in surface, central, and intermediate waters over distances of the order of 1000 km. The meridional transition contrasts with the abrupt zonal changes found in the cross-slope direction, which are of comparable magnitude but over distances of the order of 100 km. Both AAIW and SAAW (fresh and well oxygenated) partially mix with the hypoxic ESSW and, therefore, play an important role in the ventilation of the southern part of the oxygen minimum zone. 

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