Effect of the oxygen minimum zone on the second chlorophyll maximum in the Eastern Tropical Pacific off Mexico

Field data collected during June 2005 were used to determine the relationship between the second fluorescence maximum (FMax), the top of the oxygen minimum zone (OMZ), and physical processes (coastal currents, eddies, and upwelling) in the northern region of the Eastern Tropical Pacific off Mexico (...

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Bibliographic Details
Authors: J Cepeda-Morales, E Beier, G Gaxiola-Castro, MF Lavín, VM Godínez
Format: article
Status:Published version
Publication Date:2009
Country:México
Institution:Universidad Autónoma de Baja California
Repository:Redalyc-UABC
OAI Identifier:oai:redalyc.org:48013184006
Online Access:https://www.redalyc.org/articulo.oa?id=48013184006
Access Level:Open access
Keyword:Ciencias de la Tierra
eddies
euphotic zone
oxygen minimum zone
Mexican Coastal Current
Chlorophyll fluorescence
Description
Summary:Field data collected during June 2005 were used to determine the relationship between the second fluorescence maximum (FMax), the top of the oxygen minimum zone (OMZ), and physical processes (coastal currents, eddies, and upwelling) in the northern region of the Eastern Tropical Pacific off Mexico (ETPM). A recurrent second FMax was observed in the ETPM, which was formed only when the upper limit of the OMZ (9.0 ¿mol L¿1) overlapped with the 1% downwelling blue irradiance depth (Ed490). The presence of the second FMax increased the total integrated water column chlorophyll from 20% to 40%. The second FMax was absent from areas where oxygenated California Current Water (CCW) deepened the upper limit of the OMZ below 1% Ed490. The poleward Mexican Coastal Current carried less oxygenated Subtropical Subsurface Water into the area, and enabled the formation of the second FMax. The variability of the second FMax driven by mesoscale physical processes wasrelated to coastal upwelling and cyclonic eddies only in areas not influenced by CCW.