Marquez-Artavia A. auteur aut IRD Sanchez-Velasco L. auteur aut IRD Barton E. D. auteur aut IRD Paulmier Aurélien auteur aut IRD Santamaria-Del-Angel E. auteur aut IRD Beier E. auteur aut IRD text journalArticle eng text/pdf born digital access The tropical Oxygen Minimum Zones (OMZ) are known to shelter a chlorophyll-a maximum (CM) within suboxic waters (<20 mu mol kg(-1)), below other chlorophyll-a maxima and with an unknown temporal variability in the Pacific OMZ off Mexico. Here, 1161 chlorophyll-a fluorescence and oxygen profiles collected between 2003 and 2016 were used to describe statistically the physical situation in which the suboxic-CM was found. Results indicate that the suboxic-CM was a persistent feature at seasonal scale at depths between 40 and 190 m at an average density potential anomaly of 26 +/- 0.2 kg m(-3), related to the Subtropical Subsurface Water, which is nearly unaffected by mixing with other water masses. The suboxic-CM south of 21 degrees N was generally associated with the upper limit of the suboxic waters of the OMZ. In this region, the distance between the suboxic waters and the euphotic zone (1% of surface irradiance) was > - 25 m year-round, which suggests that persistent low-light levels allow development of the suboxic-CM. The persistence of the suboxic-CM is consistent with its association with a stable microbial community. The effects on the ecosystem and biogeochemical cycles remain to be investigated. specialized Chlorophyll maxima Suboxia Persistence Euphotic zone Mexican Pacific MEXIQUE PACIFIQUE 032 036 169 No Spécial art. 104686 [8p.] 2019 0967-0645 https://www.documentation.ird.fr/hor/fdi:010077727 10.1016/j.dsr2.2019.104686 0967-0645 [F B010077727] https://www.documentation.ird.fr/hor/fdi:010077727 https://www.documentation.ird.fr/intranet/publi/2020/01/010077727.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2020-02-05 2025-02-24 fdi:010077727 fre