Bottom water flows in the tropical fractures of the Northern Mid-Atlantic Ridge

The goal of this paper is to study the flows of Antarctic Bottom Water through the fracture zones in the northern part of the Mid-Atlantic Ridge based on the Conductivity-Temperature-Depth and Lowered Acoustic Doppler Current Profiler observations in 2014, 2015, and 2016. We measured the thermohaline properties and velocities and analyzed the flows of bottom water in the Strakhov, Bogdanov, nameless (07°28′N), Vernadsky, Doldrums, Arkhangelsky, Ten Degree, Vema, Marathon, Fifteen Twenty, and Kane fracture zones. These abyssal channels connect the deep basins of the East and West Atlantic. In addition to the known fact that the main portion of water propagates through the Vema Fracture Zone (11°N), we estimated that additionally a half of this volume propagates through the other fractures. Nevertheless, the pathway for the coldest water is located in the Vema Fracture Zone. Velocities of bottom currents in this fracture reach 45 cm/s. We found strong difference in the structure and transport through the Vema Fracture Zone based on four sections across the fracture occupied in 3 years from 2014 to 2016. The transport varies from 0.7 to 1.2 Sv. The core of maximum velocity in the main channel of this fracture changes its depth between 4000 m and the bottom at 4650 m. The total transport through the other fracture zones is as high as 0.48 ± 0.05 Sv.