Séminaire
Oxygen enters the ocean by the exchanges at the air-sea interface and the penetration of water masses deeper into the ocean interior. In the ocean, oxygen is consumed by the biological activity that remineralizes the sinking organic matter produced at the surface. Variations in oceanic oxygen therefore integrate variations in the ocean ventilation and biological activity. In addition, the ocean oxygen content and hence the atmospheric oxygen content are closely related to the ocean heat content. This close association explains the oceanic loss of oxygen, or deoxygenation, recently evidenced in response to the anthropogenic warming. Here, we show how variations in oceanic and atmospheric oxygen can reveal changes in the ocean ventilation and heat transports from the global climatic scales down to smaller spatio-temporal scales.