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Nutrient variability in Subantarctic Mode Waters forced by the Southern Annular Mode and ENSO


Ayers, JM and Strutton, PG, Nutrient variability in Subantarctic Mode Waters forced by the Southern Annular Mode and ENSO, Geophysical Research Letters, 40, (13) pp. 3419-3423. ISSN 0094-8276 (2013) [Refereed Article]

Copyright Statement

Copyright 2013 American Geophysical Union

DOI: doi:10.1002/grl.50638


As the primary source of nutrients to the global thermocline, Subantarctic Mode Waters (SAMWs) play a key role in primary production and climate. Here we use repeat hydrographic World Ocean Circulation Experiment/Climate Variability and Predictability data to quantify interannual SAMW nutrient variability and its forcing. Pacific sector SAMW nutrients were significantly correlated with the Southern Annular Mode (SAM) and wind stress curl anomalies associated with a faster meridional overturning circulation (MOC). A stronger MOC results in greater upwelling of nutrients at high latitudes, increased Ekman transport of nutrients equatorward, and subduction of higher preformed nutrient loads in SAMWs. Australian sector SAMWs were significantly correlated with El Niño-Southern Oscillation (ENSO), likely due to its modulation of transport in the East Australian Current extension. Interannual variability in SAMW nutrients impacts downstream tropical export production by as much as 5-12% of the annual mean. Key Points Subantarctic Mode Water nutrients vary interannually by 15-50% of the mean Wind-driven circulation forces 40-65% of Pacific sector nutrient variability Nutrient variability impacts downstream production and carbon drawdown ©2013. American Geophysical Union. All Rights Reserved.

Item Details

Item Type:Refereed Article
Keywords:Subantarctic Mode Water, Southern Annular Mode, Nutrients
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Chemical oceanography
Objective Division:Environmental Management
Objective Group:Air quality, atmosphere and weather
Objective Field:Atmospheric composition (incl. greenhouse gas inventory)
UTAS Author:Ayers, JM (Dr Jennifer Ayers)
UTAS Author:Strutton, PG (Professor Peter Strutton)
ID Code:89437
Year Published:2013
Web of Science® Times Cited:26
Deposited By:IMAS Research and Education Centre
Deposited On:2014-03-05
Last Modified:2017-11-01

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