Antarctic Krill (Euphausia superba)

Assembled from 60 blocks · 1 evidence · 89 related

1. Story
2. A shrimp-like euphausiid crustacean, a few centimetres long as an adult, that forms the single load-bearing link of the Southern Ocean food web: whales, seals, penguins, flying seabirds and fish either eat it directly or eat something that does. Its dependence on sea ice is a matter of life history rather than preference - the larvae overwinter under the pack ice, grazing the algal layer on its underside through the months when there is nothing in the open water to eat, so the extent and duration of winter ice sets how many larvae survive to the following year. A 2004 analysis of net-haul records from the Scotia Sea sector reported a long-term decline in krill density correlated with reduced winter sea-ice extent, alongside an increase in salps; the magnitude of the decline has been argued about since, but the mechanism linking recruitment to winter ice is not seriously disputed. Krill is also a commercial fishery, which puts an ecosystem bottleneck and a managed catch limit in the same accounts.
3. Knowledge
4. Sea Ice
5. Antarctic Polar Front (Antarctic Convergence)
6. Antarctic Krill (Euphausia superba)
7. Southern Ocean
8. Connections
9. Blue Whale (Balaenoptera musculus)
10. Commission for the Conservation of Antarctic Marine Living Resources
11. Baleen whale consumption is re-measured, and the krill paradox sharpens
12. Antarctic Polar Front (Antarctic Convergence)
13. Sea Ice
14. Southern Ocean
15. Emperor Penguin (Aptenodytes forsteri)
16. CCAMLR is agreed at Canberra
17. A long-term decline in krill density is linked to winter sea ice
18. CCAMLR adopts the Ross Sea marine protected area
19. Antarctic Circumpolar Current (ACC)
20. Antarctic Krill (Euphausia superba)
21. Polynya
22. Arctic Amplification
23. Antarctic Krill (Euphausia superba)
24. Polar Bear (Ursus maritimus)
25. Emperor Penguin (Aptenodytes forsteri)
26. Halley Bay Emperor Penguin Colony
27. The continuous satellite sea-ice record begins
28. A long-term decline in krill density is linked to winter sea ice
29. The Arctic summer minimum drops far below anything previously observed
30. The lowest Arctic sea-ice extent in the satellite record
31. The Halley Bay emperor colony fails and does not recover
32. The emperor penguin is listed as threatened under the US Endangered Species Act
33. Antarctic sea ice reaches a record low, a year after the previous one
34. Antarctic Blue Whale (B. m. intermedia)
35. Antarctic Summer Feeding Migration
36. South Georgia
37. Southern Ocean Whale Sanctuary
38. Seasonal Krill Aggregation
39. The factory ship Lancing takes a stern slipway south
40. The Antarctic blue whale catch reaches its all-time peak
41. The Southern Ocean Whale Sanctuary is adopted
42. Dedicated Antarctic Blue Whale Project voyages
43. Baleen whale consumption is re-measured, and the krill paradox sharpens
44. The only published Antarctic blue whale satellite tracks are released as data
45. Antarctic Krill (Euphausia superba)
46. Arctic Tern (Sterna paradisaea)
47. CCAMLR is agreed at Canberra
48. A long-term decline in krill density is linked to winter sea ice
49. CCAMLR adopts the Ross Sea marine protected area
50. Antarctic sea ice reaches a record low, a year after the previous one
51. Antarctic Circumpolar Current (ACC)
52. Antarctica
53. Thermohaline Circulation
54. North Atlantic — Grand Banks approaches
55. Weddell Sea
56. A circumpolar current becomes possible
57. Antarctic meltwater is projected to slow the abyssal cell
58. A physics-based early warning signal is proposed
59. Evidence
60. Analysis of a compiled database of scientific net hauls indicates a long-term decline in Antarctic krill density in the southwest Atlantic sector, correlated with reduced winter sea-ice extent, together with an increase in salp abundance. V55 VERIFICATION BASIS: not opened during production; no research channel was available. The magnitude of the reported decline is deliberately not quoted anywhere in this pack, because subsequent work has contested it and the figure could not be checked.