Earth's Waters Are Losing Oxygen, Scientists Warn

Scientists, led by UC San Diego's Scripps Institution of Oceanography, are warning that oxygen is rapidly disappearing from oceans and freshwater systems, potentially pushing the planet into an "unsafe space." This widespread deoxygenation is closely connected to other major planetary threats, including warming, pollution, biodiversity loss, and ocean acidification.

A new review examines aquatic deoxygenation, referring to declining levels of dissolved oxygen in oceans, coastal waters, rivers, lakes, and streams. Researchers assessed how this growing problem interacts with the nine major Earth system processes included in the Planetary Boundaries framework. They argue that dissolved oxygen levels should also be formally included in this framework.

Human-caused warming, excessive nutrient pollution, and changes in the movement and ventilation of deeper waters are the main forces driving aquatic deoxygenation. As oxygen levels fall, they can disrupt biological and chemical processes that help regulate Earth's climate and threaten organisms across aquatic food webs, from microscopic life to fish and sharks.

Lead author Erica Ferrer and senior author Lisa Levin hope the findings will encourage researchers and policymakers to examine aquatic oxygen loss alongside climate change, pollution, and biodiversity decline, rather than treating it as a separate problem. Ferrer emphasizes that mitigating its impacts represents a critical component of maintaining biodiversity and climate.

Source