Pathways of oxygen supply into the Eastern South Pacific Oxygen Minimum Zone

Abstract

We use climatological and Argo program data to look at the ventilation patterns of the Tropical Eastern South Pacific (TESP) Oxygen Minimum Zone (OMZ). Streamlines of volume transport and contours of accumulated oxygen transport (through advection and epipycnal turbulent diffusion) are computed for the whole TESP. In particular, we provide a novel description of the southern/subtropical pathway and compare its relevance with the recently described (Stramma et al. 2010) equatorial pathway of oxygen supply. In addition, we analyse the annual oxygen budget for the ESP OMZ core. The importance of each term (advection, epipycnal and diapycnal turbulent diffusion, and biological consumption) is examined for several isoneutral layers. The slight imbalances obtained when computing the oxygen budget within each isoneutral layer cast light on the expected mean oxygen changes at different depth regimes of the TESP OMZ