The western boundary undercurrent as a turbidity maximum over the Puerto Rico Trench

Abstract

Nephelometer measurements in the Puerto Rico trench record a midwater light scattering maximum at the depth of the near‐bottom nepheloid layer found in the deep Atlantic basin to the northwest. This midwater maximum is best developed near the south slope of the trench and is interpreted as a southeasterly continuation of the western boundary undercurrent, which has been documented along the continental rise of eastern North America. The eastward‐advecting core of the flow overrides clearer colder antarctic bottom water that enters the trench from the east. A near‐bottom nepheloid layer, best developed in the eastern part of the trench, appears to be associated with the westward‐flowing antarctic bottom current.

Distribution of suspended particulate matter at the equatorial transect in the Atlantic Ocean

“…The "dam" blocks the lower part of Antarctic Bottom Water flow and coinciding BNL at the depth of 4500 m, creating the INL from BNL. One of the most notable similar nephelometric features was described for the Puerto Rico Trench near the Navidad sill (Tucholke and Eittreim, 1974). The BNL to the east of the Antarctic Bottom Water flow core is likely caused by Antarctic Bottom Water southward recirculation (Sarafanov et al, 2007).…”

Decadal Comparisons of Particulate Matter in Repeat Transects in the Atlantic, Pacific, and Indian Ocean Basins

“…BNLs exist along the entire transect in both years but are strongest between 30 and 40°N and stronger in 2012 than 2003. The small intermediate nepheloid layer 200–500 mab at 22°N occurs above the Greater Antilles Outer Ridge and is likely the intermediate nepheloid layer described by Tucholke and Eittreim () carrying fine clays from the western North Atlantic.…”