A circumpolar current becomes possible

Assembled from 50 blocks · 1 evidence · 83 related

1. Story
2. The opening of Drake Passage and the deepening of the Tasman gateway removed the last land barriers between the Atlantic, Pacific and Indian oceans at southern high latitudes, allowing an unbroken eastward current around Antarctica. When this happened is genuinely disputed: estimates cluster around the Eocene–Oligocene transition near 34 Ma, around 31 Ma from foraminiferal and neodymium evidence, near 30 Ma from gateway–westerly alignment arguments, and near 24 Ma from flow-speed and water-mass homogeneity records, while a 2023 study argues the modern ACC was not established until the late Miocene. The pack states the disagreement rather than choosing.
3. Knowledge
4. Antarctic Circumpolar Current (ACC)
5. Southern Ocean
6. Drake Passage
7. A circumpolar current becomes possible
8. Connections
9. Antarctic Circumpolar Current (ACC)
10. Drake Passage
11. Southern Ocean
12. Antarctica
13. Antarctic Polar Front (Antarctic Convergence)
14. Atlantic Meridional Overturning Circulation (AMOC)
15. Drake Passage
16. Southern Ocean
17. Drake Passage
18. A circumpolar current becomes possible
19. Drake Passage is measured and the ACC turns out to be larger
20. Antarctic Circumpolar Current (ACC)
21. Antarctic Circumpolar Current (ACC)
22. A circumpolar current becomes possible
23. Drake Passage is measured and the ACC turns out to be larger
24. Antarctic Blue Whale (B. m. intermedia)
25. Antarctic Summer Feeding Migration
26. South Georgia
27. Southern Ocean Whale Sanctuary
28. Seasonal Krill Aggregation
29. The factory ship Lancing takes a stern slipway south
30. The Antarctic blue whale catch reaches its all-time peak
31. The Southern Ocean Whale Sanctuary is adopted
32. Dedicated Antarctic Blue Whale Project voyages
33. Baleen whale consumption is re-measured, and the krill paradox sharpens
34. The only published Antarctic blue whale satellite tracks are released as data
35. Antarctic Krill (Euphausia superba)
36. Arctic Tern (Sterna paradisaea)
37. CCAMLR is agreed at Canberra
38. A long-term decline in krill density is linked to winter sea ice
39. CCAMLR adopts the Ross Sea marine protected area
40. Antarctic sea ice reaches a record low, a year after the previous one
41. Antarctic Circumpolar Current (ACC)
42. Antarctica
43. Thermohaline Circulation
44. North Atlantic — Grand Banks approaches
45. Weddell Sea
46. A circumpolar current becomes possible
47. Antarctic meltwater is projected to slow the abyssal cell
48. A physics-based early warning signal is proposed
49. Evidence
50. The timing of ACC onset is contested: this paper places the modern ACC in the late Miocene, while other studies place onset near the Eocene–Oligocene transition (~34 Ma), at ~31 Ma from foraminiferal and neodymium evidence, at ~30 Ma from Tasmanian gateway–westerly alignment, and at ~24 Ma from flow-speed and water-mass homogeneity records. The disagreement is stated, not resolved; none of the papers was fetched.