Abyssopelagic Zone (Abyssal Zone)

Assembled from 23 blocks · 3 evidence · 19 related

1. Story
2. Conventionally about 4,000 m to 6,000 m, overlying the abyssal plains that make up the largest single habitat type on the planet by area. Permanently dark, near-freezing, and food-limited: the abyssal seafloor lives almost entirely on the small fraction of surface primary production that survives the fall as marine snow. The 4,000 m and 6,000 m limits are agreed conventions rather than measured discontinuities; the 6,000 m figure in particular is a working definition chosen because trench faunas below it start to look distinct.
3. Knowledge
4. Abyssopelagic Zone (Abyssal Zone)
5. Hadal Zone
6. Connections
7. Bathypelagic Zone (Midnight Zone)
8. Hadal Zone
9. Mariana Trench
10. Marine Snow
11. Abyssopelagic Zone (Abyssal Zone)
12. Mariana Trench
13. Challenger Deep
14. DSV Limiting Factor (Triton 36000/2)
15. Trieste reaches the bottom of the Challenger Deep
16. JAMSTEC's Kaiko reaches the Challenger Deep floor
17. First solo crewed dive to the Challenger Deep
18. Five Deeps Expedition dives the Challenger Deep four times
19. Revised depth of the Challenger Deep published
20. Evidence
21. Sunlight does not penetrate below roughly 1,000 m; the aphotic zone below that comprises the bathypelagic (1,000-4,000 m), the abyss (4,000-6,000 m) and the hadal (6,000 m and deeper). Attenuation is continuous, and these depths are stated as conventional bands, not measured discontinuities.
22. The water column is conventionally divided into five zones - sunlight (epipelagic, 0-200 m), twilight (mesopelagic, 200-1,000 m), midnight (bathypelagic, 1,000-4,000 m), abyssal (abyssopelagic, 4,000-6,000 m) and hadal (below 6,000 m).
23. Sediment-trap measurements indicate that only a small percentage of surface primary production reaches the deep seafloor - of the order of 3-4 percent in the subarctic Pacific - and that around 99 percent of the organic carbon arriving is consumed rather than buried.