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Upwelling in the world's strongest current, the Antarctic Circumpolar Current, is thought to be driven by wind stress, surface buoyancy flux, and mixing generated from the interaction between bottom currents and rough topography. However, the impact of localized injection of heat by hydrothermal vents where the Antarctic Circumpolar Current interacts with mid-ocean ridges remains poorly understood. Here a circumpolar compilation of helium and physical measurements are used to show that while geothermal heat is transferred to the ocean over a broad area by conduction, heat transfer by convection dominates near hydrothermal vents. Buoyant hydrothermal plumes decrease stratification above the vent source and increase stratification to the south, altering the local vertical diffusivity and diapycnal upwelling within 500 m of the sea floor by an order of magnitude. Both the helium tracer and stratification signals induced by hydrothermal input are advected by the flow and influence properties downstream.

Item Type:	Refereed Article
Keywords:	hydrothermal plumes, geothermal heat, Southern Ocean, vertical mixing, upwelling, Antarctic Circumpolar Current
Research Division:	Earth Sciences
Research Group:	Oceanography
Research Field:	Physical oceanography
Objective Division:	Environmental Management
Objective Group:	Management of Antarctic and Southern Ocean environments
Objective Field:	Antarctic and Southern Ocean oceanic processes
UTAS Author:	Downes, SM (Dr Stephanie Downes)
UTAS Author:	Rintoul, SR (Dr Steve Rintoul)
ID Code:	133811
Year Published:	2019
Web of Science® Times Cited:	1
Deposited By:	CRC-Antarctic Climate & Ecosystems
Deposited On:	2019-07-11
Last Modified:	2020-01-06
Downloads:	36 View Download Statistics