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.