Study warns aquatic deoxygenation pushes Earth toward unsafe state
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A new review in Limnology and Oceanography led by Scripps Institution of Oceanography warns that rapid oxygen loss from oceans, lakes, and rivers is pushing Earth toward an "unsafe space" with potentially irreversible consequences. The study proposes adding dissolved oxygen conditions to the Planetary Boundaries framework, which tracks critical Earth system processes.
The Planetary Boundaries Framework
First introduced in 2009, the framework identifies nine critical Earth system processes, including climate change, ocean acidification, and biodiversity loss. The authors argue that aquatic deoxygenation interacts with all nine boundaries, amplifying risks. Lead author Erica Ferrer of UC Santa Barbara said the study aims to elevate deoxygenation as a global threat that does not operate in isolation.
Drivers and Impacts
Aquatic deoxygenation is driven primarily by human-caused warming, excess nutrient pollution, and changes in water ventilation. Oxygen loss disrupts biological and chemical processes that regulate climate and threatens aquatic life from microorganisms to fish and sharks. Even marine mammals that breathe air are affected as oxygen loss alters their prey and habitats.
Research Origins and Goals
Ferrer and Scripps biological oceanographer Lisa Levin conceived the paper after attending COP25 in Madrid in 2019. They hope the review encourages scientists and policymakers to consider deoxygenation alongside other planetary stressors. Ferrer stated that adding deoxygenation to the framework will help understand its impact on Earth system stability.
South African fish stocks at risk
Marine scientists in South Africa warn that rising sea temperatures are causing oxygen depletion, endangering fish stocks. Small-scale coastal fishing communities are particularly vulnerable as some fish species migrate to colder waters.
What's Next
The study is expected to inform discussions at upcoming climate and biodiversity conferences. It remains unclear whether the Planetary Boundaries framework will formally adopt dissolved oxygen as a tenth boundary.
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Study warns aquatic deoxygenation pushes Earth toward unsafe state
