Almaraz-Ruiz L., Machain-Castillo M., Sifeddine Abdelfettah, Ruiz-Fernández A., Sanchez-Cabeza J. A., Rodríguez-Ramírez A., Mendez-Millan Mercedes, Caquineau Sandrine. (2024). Changes of bottom water oxygenation during the last half millennium in the Gulf of Tehuantepec (Eastern Tropical North Pacific) : A multiproxy approach. Palaeogeography Palaeoclimatology Palaeoecology, 636, 111994 [13 p.]. ISSN 0031-0182.
Titre du document
Changes of bottom water oxygenation during the last half millennium in the Gulf of Tehuantepec (Eastern Tropical North Pacific) : A multiproxy approach
Année de publication
2024
Auteurs
Almaraz-Ruiz L., Machain-Castillo M., Sifeddine Abdelfettah, Ruiz-Fernández A., Sanchez-Cabeza J. A., Rodríguez-Ramírez A., Mendez-Millan Mercedes, Caquineau Sandrine
Source
Palaeogeography Palaeoclimatology Palaeoecology, 2024,
636, 111994 [13 p.] ISSN 0031-0182
The Gulf of Tehuantepec (GoT), in the Eastern Tropical North Pacific Ocean, is home to one of the largest and more intense Oxygen Minimum Zones (OMZ). To identify the OMZ variability during the last five hundred years in the GoT, we analyzed the temporal variations of benthic foraminiferal (BF) assemblages, enrichment of redox-sensitive elements (Mo, V, Cd, U, and Re) and delta 15Nsed , on a laminated sediment core. During the Little Ice Age (LIA;-1500 to-1860 CE), the BF assemblages showed high dominance, and the most abundant BF species in the sediments were Epistominella sandiegoensis , Takayanagia delicata , and Buliminella tenuata. This assemblage can withstand the lowest dissolved oxygen conditions, indicating an intensified OMZ consistent with the enrichment of Mo, Re, Cd, U, and enhanced denitrification. During the Current Warm Period (CWP;-1860 CE to present), the BF assemblages were more diverse, and the most abundant species were Bolivina seminuda, Epistominella sp.1, Gyroidina nitidula , and Suggrunda eckisi , an assemblage less tolerant to low dissolved oxygen conditions, together with lower concentrations of redox-sensitive elements and delta 15Nsed , suggest weakening of the reducing conditions within the OMZ. Additionally, our BF data showed evidence of the influence of the Pacific Decadal Oscillation on bottom-water oxygenation. Bottom-water oxygenation changes appear to respond to increased solar forcing caused by Intertropical Convergence Zone migration and strengthened Pacific Walker Circulation, which in turn modulated productivity, organic matter flux to the seabed, and oxygen consumption in the bottom water. Our findings agree with previous studies further north from the study site, indicating these changes' regional scale.
Plan de classement
Sciences du milieu [021]
;
Géologie et formations superficielles [064]
Description Géographique
PACIFIQUE ; MEXIQUE ; ZONE TROPICALE
Localisation
Fonds IRD [F B010089469]
Identifiant IRD
fdi:010089469
