Hadal Zone

Assembled from 18 blocks · 3 evidence · 17 related

1. Story
2. Conventionally everything deeper than about 6,000 m - in practice the trenches and trough systems, which are geographically fragmented rather than a continuous global layer. Named for Hades. The hadal is not a band of open ocean like the zones above it: it exists only where the seafloor is dragged down at subduction zones, so it is a set of disconnected deep pockets. Pressure at its deepest point exceeds 1,000 atmospheres, and that pressure - not darkness, not cold - is what has limited human and robotic access.
3. Knowledge
4. Hadal Zone
5. Connections
6. Abyssopelagic Zone (Abyssal Zone)
7. Mariana Trench
8. Challenger Deep
9. DSV Limiting Factor (Triton 36000/2)
10. Trieste reaches the bottom of the Challenger Deep
11. JAMSTEC's Kaiko reaches the Challenger Deep floor
12. First solo crewed dive to the Challenger Deep
13. Five Deeps Expedition dives the Challenger Deep four times
14. Revised depth of the Challenger Deep published
15. Evidence
16. 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).
17. 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.
18. Submersible transects conducted in June 2020 yield a revised Challenger Deep floor depth of 10,935 m (+/- 6 m at 95 percent confidence) below mean sea level. Earlier direct measurements include DEEPSEA CHALLENGER at 10,908 +/- 3 m and its landers at 10,918 +/- 3 m (2012).