Earth's Oceans Are Rapidly Losing Oxygen. It Could Destabilize the Planet

Key Points:

• Scientists warn that oxygen levels in the world’s aquatic ecosystems are rapidly declining due to human activities, posing a serious threat to the biosphere and aquatic life.
• A new review published in Limnology and Oceanography advocates for adding aquatic deoxygenation as a tenth boundary to the Planetary Boundaries framework, which currently tracks nine critical Earth system processes.
• Rising global temperatures reduce dissolved oxygen in water, while nutrient pollution from agriculture and industry fuels algal blooms that consume oxygen, exacerbating oxygen loss in oceans, lakes, and rivers.
• The ocean has lost about 2% of its dissolved oxygen since the 1950s, with projections of an additional 1% to 7% loss by 2100, which can severely disrupt aquatic ecosystems even with seemingly small reductions.
• The researchers propose specific indicators to monitor aquatic deoxygenation and emphasize the urgent need for global recognition and action to prevent irreversible damage to Earth’s aquatic environments.