| Domain | Oceanic | Description | Oxygen is essential for all higher life. Future projections indicate that oceanic oxygen levels will decrease substantially, in part because of ocean warming and increased stratification, a process often referred to as ocean deoxygenation, but also because of increased nutrient loadings in nearshore environments that lead to eutrophication. In a business-as-usual scenario, the ocean is projected to lose nearly 20% of its oxygen. This could have dramatic consequences for marine biogeochemistry and marine life, as the ocean’s oxygen minimum zones will expand substantially, and large swaths of ocean will appear that have oxygen levels too low for fast swimming fish to survive, and can potentially reduce the pool of bio-available nitrogen due to reduction of nitrate.
Oxygen is also is an excellent tracer for ocean circulation and ocean biogeochemistry. [GCOS-195 5.4.7] |