Localizing the Southern Ocean biogeochemical divide

• Published in: Geophysical Research Letters
• Main Authors: Xie, Y, Tamsitt, V, Bach, LT
• Format: Article in Journal/Newspaper
• Language: English
• Published: Amer Geophysical Union 2022
• Subjects: Earth Sciences; Oceanography; Physical oceanography; Antarctic; Southern Ocean; The Antarctic; Antarc*; Sea ice
• Online Access: https://doi.org/10.1029/2022GL098260; http://ecite.utas.edu.au/155106

The meridional overturning circulation consists of an upper and lower cell. The Southern Ocean Biogeochemical Divide (SOBD) is the boundary between the two cells in the surface of the Southern Ocean, but its location is poorly constrained. Localizing the SOBD is important because biological nutrient utilization north and south of the SOBD have fundamentally different consequences for global ocean primary production and carbon sequestration. Here, we aim to localize the SOBD by releasing virtual Lagrangian particles south of 40S in an eddying ocean sea-ice model and compare simulation results with observations. We find that the SOBD is a circumpolar band, where different sectors are shaped by different oceanographic features: (a) Ekman transport, (b) the γ =27.6kg m −3 neutral density outcrop, and (c) fronts associated with the Antarctic Circumpolar Current. Our findings help to understand how nutrient utilization in different parts of the Southern Ocean affects the biologically driven carbon sequestration.