The Ice Age That Nearly Wiped Out Ocean Life | Documentary For Sleep

Now on Spotify 🎧 Listen here: https://open.spotify.com/show/033Kcgn9MvUZnvXK7B8k71 Long before forests covered the continents or animals walked far inland, life was concentrated in the seas — and then the oceans were hit by one of the sharpest climate shocks in Earth’s history. This video explores the Hirnantian glaciation, the intense late Ordovician ice age linked to one of the first great mass extinctions. As ice spread across ancient Gondwana, sea levels fell, shallow marine habitats vanished, ocean chemistry shifted, and countless species that depended on warm continental seas were pushed toward collapse. The disaster did not come from a single impact or eruption. It came from climate swinging hard in two directions: first into cold, as glaciers locked away water and drained the seas from coastal shelves, then back toward warming, as melting ice returned water to the oceans and disrupted them again. Life faced not one crisis, but a sequence of changing worlds. The documentary follows how brachiopods, trilobites, corals, graptolites, and many other marine organisms were caught in a planet-wide transformation. In an ocean-dominated world, losing shallow seas meant losing entire ecosystems. What survived had to endure cold, habitat loss, oxygen changes, and the instability that followed. The Hirnantian glaciation reminds us that ice ages are not always slow background events. Sometimes they arrive as evolutionary turning points, reshaping the oceans and deciding which branches of life continue into the future. If you feel like sharing, mention where you’re watching from and what time it is there — then imagine ancient seas retreating from the continents, while glaciers grow in the distance and ocean life struggles through one of Earth’s earliest great extinctions. Sources: Delabroye & Vecoli — https://www.sciencedirect.com/science/article/pii/S0012825209001652 Armstrong et al. — https://www.sciencedirect.com/science/article/abs/pii/S0031018205000246 Cocks & Rong — https://www.cambridge.org/core/journals/earth-and-environmental-science-transactions-of-royal-society-of-edinburgh/article/abs/earliest-silurian-faunal-survival-and-recovery-after-the-end-ordovician-glaciation-evidence-from-the-brachiopods/558E34ABB39CC5DE0E24007CDA670931 Xu et al. — https://www.cambridge.org/core/journals/journal-of-paleontology/article/abs/patterns-and-processes-of-latest-ordovician-graptolite-extinction-and-recovery-based-on-data-from-south-china/2A2E857FBC888D5DAABE6088A60EC94B Edwards et al. — https://www.nature.com/articles/s41561-023-01287-z