Menezes, V., Furey, H., Torres, D., Bahr, F., & Baker, L. (2026). Direct Observations of Strong Jets Transporting Deep and Bottom Water Into the Indian Ocean Through the Fracture Zones of the Southwest Indian Ridge. Journal of Geophysical Research – Oceans, 131(3), e2025JC023864.https://doi.org/10.1029/2025jc023864
Figure courtesy of Viviane de Menezes
The Deep Madagascar Basin Experiment was designed to study the pathways of the Antarctic Bottom Water (AABW) into the subtropics in the Southwest Indian Ocean. Particular focus was given to the meridionally oriented, narrow fracture zones of the Southwest Indian Ridge, which separate the Crozet Basin in the Southern Ocean from the Madagascar Basin in the subtropics. These fracture zones serve as chokepoints for the abyssal overturning circulation. In this paper, we report the discovery of two strong abyssal jets transporting Antarctic Bottom Water northward and assess the strength of diapycnal turbulent mixing in the region. One jet was identified at the Novara fracture zone (46 cm/s), where turbulent mixing in the abyss is weak. The second jet was detected at the Melville fracture zone (24 cm/s), where abyssal mixing is high. These newly identified jets complement the previously known deep jet in the Atlantis II fracture zone, which was also measured during the experiment.