Valdes J., Sifeddine Abdelfettah, Guinez M., Castillo A. (2021). Oxygen minimum zone variability during the last 700 years in a coastal upwelling area of the Humboldt system (Mejillones, 23° S, Chile). A new approach from geochemical signature. Progress in Oceanography, 193, 102520 [12 p.]. ISSN 0079-6611.
Titre du document
Oxygen minimum zone variability during the last 700 years in a coastal upwelling area of the Humboldt system (Mejillones, 23° S, Chile). A new approach from geochemical signature
Valdes J., Sifeddine Abdelfettah, Guinez M., Castillo A.
Source
Progress in Oceanography, 2021,
193, 102520 [12 p.] ISSN 0079-6611
Mejillones bay presents a permanent and shallow OMZ, whose upper boundary fluctuates between 30 m and 60 m water depth during a normal year. Under this condition, the bottom sediments preserve a geochemical signature of the past oceanic variability. Particularly, biological productivity and bottom dissolved oxygen can be reconstructed using 13C, 15N and trace elements metals measured along sediment cores. Trace elements like V, Ni, Mo and U preserved in surface sediment of Mejillones bay as a consequence of poorly oxygenated bottom waters, were used to develop a statistical model that allowed the reconstruction of the bottom water dissolved oxygen variability during the last 700 years. During these seven centuries, the marine sediments of Mejillones recorded three ocean-climatic periods. From 1350 to 1500 CE the bay was dominated by a strong and shallower OMZ, intense denitrification, but a low productivity and flux of biodetritus. Bottom waters recorded oxygen values around a mean of 3.52 mu
