hadal

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hadal

[′hād·əl]
(oceanography)
Pertaining to the environment of the ocean trenches, over 4 miles (6.5 kilometers) in depth.
References in periodicals archive ?
In contrast, silicate profiles in the hadal zone (Fig.
2a) in the hadal zone showed a slightly increasing trend with depth at both AN1 and LM2.
The higher and lower values of potential temperature and dissolved oxygen, respectively, at ~6000 m depth over the hadal zone were supported by the CLIVAR and GO-SHIP data gathered across the Izu-Ogasawara Trench between 142.
2a, 3a, and 4a) might reflect effective accumulation of crustal heat flow in the hadal zone.
It is uncertain why the slope of temperature increase in the hadal zone at AN1 and LM2 (~0.
In contrast, the profile in 1994 (at LM2) was almost constant through the hadal zone.
The D-values were nearly constant in the hadal zone for all the trace metals.
29) reported sharp increases of TD-Fe and TD-Mn in a hadal zone of the Japan Trench, reaching maximum values of 113 nM and 12 nM, respectively, at ~10 m above the bottom at station LM9 (40[degrees]26'N, 144[degrees]29'E; depth = 7375m) on October 16, 1994.
222]Rn observed at 2692 m above the bottom at AN1 to have been supplied only from the trench bottom sediment, there would need to have been extraordinary vigorous vertical mixing with a time scale of only several days through the hadal zone.
222]Rn flux from the trench walls implies the existence of lateral fluxes for other chemical components in the hadal zone.
Detailed water geochemistry of the hadal zone of the Izu-Ogasawara Trench (29[degrees]05'N, 142[degrees]51'E; depth = ~768 m) was investigated in 1984 and 1994, and can be summarized as follows:
3) More frequent and/or time-series observations for water geochemistry are needed in the hadal zone to clarify potential linkages between chemical variations in trench waters and nearby seismic activities.