Oceans Run Low on Oxygen, Threatening Earth's Balance

A new review warns that warming oceans and nutrient runoff are depleting dissolved oxygen in water bodies, with global ocean oxygen down ~2% since the 1950s and potentially falling another 1–7% by 2100, a trend that could disrupt aquatic ecosystems and destabilize the biosphere; the study argues aquatic deoxygenation should be added to the Planetary Boundaries framework, proposing indicators like dissolved oxygen concentration, proximity to capacity, shifts in oxygen‑sensitive species, and the Metabolic Index to track risk.