Dissolved Oxygen Anomalies as Proxy for Variations in Ocean Circulation

Globally oceanic oxygen observations indicate ongoing continuous decrease, but the South Atlantic Ocean has a distinct multi annual cycle. Below 2000m changes in dissolved oxygen are caused by changing circulation or reduced ventilation. Other causes can be ruled out at that depth. We show that variations in the South Atlantic Oxygen distribution can be used as proxy for changes in circulation and/or overturning, due to its distinct distribution and gradient across the basin. Thus change in the circulation can be traced back for the time of sufficient oxygen measurements, extending the timeframe to the 1960ies.