Scientists warn of oxygen depletion in Earth's waters
Oxygen levels in oceans and freshwater systems are dangerously declining.
1Oxygen crisis in aquatic ecosystems
Scientists led by Scripps Institution of Oceanography revealed that dissolved oxygen levels in oceans and freshwater systems are rapidly declining. This could push the planet into an 'unsafe space.' Some changes may persist for centuries and could be irreversible within human lifetimes.
2Planetary Boundaries framework
Researchers examined aquatic deoxygenation in relation to Earth system processes using the Planetary Boundaries framework. Introduced in 2009, this framework identifies environmental processes crucial for maintaining a stable planet. The study argues that dissolved oxygen levels should be formally included in this framework.
3Main causes: warming and pollution
Human-induced global warming, excessive nutrient pollution, and changes in deep-water movement are primary drivers of aquatic oxygen loss. Declining oxygen levels can disrupt biological and chemical processes that help regulate Earth's climate, threatening aquatic food webs from microscopic life to fish and sharks.
4Marine mammals also at risk
Even though marine mammals breathe air at the surface, oxygen loss affects them by reducing or relocating prey, damaging habitats, and altering food webs. This could have long-term impacts on the health and stability of marine ecosystems, with cascading effects throughout the aquatic environment.
5Call for global policy action
Researchers developed this review after the 2019 UN Climate Change Conference (COP25). They hope findings will encourage policymakers to address aquatic oxygen loss alongside climate change, pollution, and biodiversity decline. Oxygen depletion must be treated as part of an integrated approach rather than an isolated issue.
6Critical warning for the future
The study emphasizes that mitigating aquatic oxygen loss is crucial for preserving biodiversity and climate stability. Lead author Erica Ferrer from UC Santa Barbara states, 'Our planet's health depends on aquatic ecosystems, which need oxygen to function normally,' highlighting the urgency of the situation.