Antarctica’s Ancient Ice Cycles Once Controlled Life in Distant Oceans

New research shows Antarctic ice-sheet cycles affected subtropical ocean productivity about 34 million years ago.

Scientists analyzed chemical signals in ocean sediment cores collected from JOIDES Resolution expeditions (2020–2022).

The 40,000-year obliquity cycle had a dominant influence on nutrient delivery and bioproductivity during the early Antarctic ice expansion.

The study was led by University of Wisconsin–Madison researchers and published in PNAS on 9 March 2026.