An oxygen profile at an oceanic location with an oxygen minimum zone (OMZ), like the ones found in the Arabian Sea and off the California Coast, SW Africa, and the Peru. It shows high oxygen near the sea surface, low oxygen in the OMZ at mid-depth, and the increase in oxygen in the water column below the OMZ. Typical depths for the OMZ are 1 km water below sea level, although the precise depths of these features vary with geographic location and over time at a particular site.