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Hydrothermal heat enhances abyssal mixing in the Antarctic Circumpolar Current

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posted on 2023-05-20, 05:30 authored by Stephanie Downes, Sloyan, BM, Stephen Rintoul, Lupton, JE
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.

History

Publication title

Geophysical Research Letters

Volume

46

Pagination

812-821

ISSN

0094-8276

Department/School

Institute for Marine and Antarctic Studies

Publisher

Amer Geophysical Union

Place of publication

2000 Florida Ave Nw, Washington, USA, Dc, 20009

Rights statement

Copyright 2019 American Geophysical Union

Repository Status

  • Open

Socio-economic Objectives

Antarctic and Southern Ocean oceanic processes

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