EMB Future Science Brief No. 10: Ocean Oxygen

The EMB Future Science Brief on Ocean oxygen, titled "Ocean oxygen: the role of the Ocean in the oxygen we breathe and the threat of deoxygenation", outlines the most recent science on Ocean oxygen, its influence on global oxygen cycling, and on the oxygen we breathe. The document also covers in length the issue of oxygen loss in the Ocean, termed Ocean deoxygenation. The consequences of oxygen loss in the Ocean include decreased biodiversity, shifts in species distributions, displacement or reduction in fisheries resources, changes in biogeochemical cycling, and mass mortalities. Low oxygen conditions also drive other chemical processes which produce greenhouse gases, toxic compounds and further degrade water quality. These changes are taking place on such a large scale that experts foresee that they will have implications for the global biochemistry and climate, with a less productive Ocean and a lower capacity of both land and Ocean to serve as carbon sinks.

This Future Science Brief and its recommendations support the following objectives and enablers of the EU Mission Restore our Ocean and Waters:
1) Objective: Protect and restore marine and freshwater ecosystems and biodiversity: The document addresses this objective by highlighting the threats of Ocean deoxygenation to marine life and ecosystems, and thus the importance of protection and restoration to increase resilience.
2) Objective: Prevent and eliminate pollution: This Future Science Brief describes the direct link between anthropogenic nutrient run-off and hypoxia in coastal waters, which frequently leads to changes in the community structure and mass mortality. It therefore stresses the need to limit runoff of nutrients and organic waste into the Ocean.
3) Objective: Make the sustainable blue economy carbon-neutral and circular: This document explains the direct link between anthropogenic greenhouse gas emission and Ocean deoxygenation, stressing the need to transition to a carbon-neutral economy.
4) Enabler: Promote a participatory governance based on public mobilisation and engagement: Ocean deoxygenation is a significant threat to marine ecosystems, yet it is currently heavily under-communicated compared to similar stressors, such as Ocean acidification. Awareness about Ocean deoxygenation needs to increase and participatory governance and engagement will be key to increase public awareness. This document contributes to heightening awareness of the threat of Ocean deoxygenation.