Orca Basin, Anoxic Depression on the Continental Slope, Northwest Gulf of Mexico

1978 ◽  
pp. 303-311 ◽  
Keyword(s):  
Gulf Of Mexico ◽  
Continental Slope ◽  
Orca Basin

Nearsurface Geology of the Gulf of Mexico Continental Slope

1989 ◽  
Author(s):  
J.M. Coleman ◽  
A.H. Bouma ◽  
D.B. Prior ◽  
H.H. Roberts
Keyword(s):  
Gulf Of Mexico ◽  
Continental Slope

Upper Quaternary strata of the upper continental slope, Northeast Gulf of Mexico; sequence stratigraphic model for a terrigenous shelf edge

1998 ◽  
Vol 68 (4) ◽  
pp. 579-595 ◽  
Author(s):  
R. D. Winn ◽  
H. H. Roberts ◽  
B. Kohl ◽  
R. H. Fillon ◽  
J. A. Crux ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Continental Slope ◽  
Shelf Edge ◽  
Sequence Stratigraphic ◽  
Stratigraphic Model

scholarly journals Vertical marine snow distribution in the stratified, hypersaline, and anoxic Orca Basin (Gulf of Mexico)

Elem Sci Anth ◽  
2019 ◽  
Vol 7 ◽  
Author(s):  
Arne Diercks ◽  
Kai Ziervogel ◽  
Ryan Sibert ◽  
Samantha B. Joye ◽  
Vernon Asper ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Gulf Of Mexico ◽  
Particle Number ◽  
Sea Surface ◽  
Marine Snow ◽  
Particle Volume ◽  
Total Particle Number ◽  
Total Particle ◽  
Snow Distribution ◽  
Orca Basin

We present a complete description of the depth distribution of marine snow in Orca Basin (Gulf of Mexico), from sea surface through the pycnocline to within 10 m of the seafloor. Orca Basin is an intriguing location for studying marine snow because of its unique geological and hydrographic setting: the deepest ~200 m of the basin are filled with anoxic hypersaline brine. A typical deep ocean profile of marine snow distribution was observed from the sea surface to the pycnocline, namely a surface maximum in total particle number and midwater minimum. However, instead of a nepheloid (particle-rich) layer positioned near the seabed, the nepheloid layer in the Orca Basin was positioned atop the brine. Within the brine, the total particle volume increased by a factor of 2–3 while the total particle number decreased, indicating accumulation and aggregation of material in the brine. From these observations we infer increased residence time and retention of material within the brine, which agrees well with laboratory results showing a 2.2–3.5-fold reduction in settling speed of laboratory-generated marine snow below the seawater-brine interface. Similarly, dissolved organic carbon concentration in the brine correlated positively with measured colored dissolved organic matter (r2 = 0.92, n = 15), with both variables following total particle volume inversely through the pycnocline. These data indicate the release of dissolved organic carbon concomitant with loss in total particle volume and increase in particle numbers at the brine-seawater interface, highlighting the importance of the Orca Basin as a carbon sink.

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