Data for "Irreversible Southern Ocean Silicate Front contraction and global nutrient depletion"

The Southern Ocean (SO) controls nutrient quantity and composition exported to lower latitudes via the biological pump. Biological activity in the SO blocks northward nutrient transport and traps nutrients within SO deep waters, reinforcing its role in global redistribution. The Silicate Front (SF) in the SO serves as a proxy for these processes. CESM2 simulations under global warming and climate mitigation scenarios reveal that coupled atmosphere-ocean responses enhance horizontal iron advection into the SF region, triggering diatom blooms. These blooms accelerate silicate (SiO₃) uptake, decreasing surface SiO₃and driving poleward SF contraction. Even after CO₂ emissions decline, irreversible air–sea dynamics sustain elevated iron supply and diatom productivity, prolonging SF contraction with modest, delayed recovery. Therefore, deep-water nutrient trapping and euphotic-layer depletion are projected to persist and worsen irreversibly. Observed SF contraction indicates that a global warming–driven nutrient cycle collapse is already underway.