Australian dust storms in 2002-2003 and their impact on Southern Ocean biogeochemistry

Type Article
Date 2010-06
Language English
Author(s) Gabric A. J.1, Cropp R. A.1, McTainsh G. H.1, Johnston B. M.1, Butler H.2, Tilbrook B.4, Keywood M.3
Affiliation(s) 1 : Griffith Univ, Sch Environm, Nathan, Qld 4111, Australia.
2 : Univ So Queensland, Dept Math & Comp, Toowoomba, Qld 4350, Australia.
3 : CSIRO Marine & Atmospher Res, Aspendale, Vic 3195, Australia.
4 : CSIRO Marine & Atmospher Res, Hobart, Tas 7001, Australia.
Source Global Biogeochemical Cycles (0886-6236) (Amer Geophysical Union), 2010-06 , Vol. 24 , N. 2/GB2005 , P. 1-17
DOI 10.1029/2009GB003541
WOS© Times Cited 46
Abstract During late 2002 and early 2003, southern Australia was in the grip of drought and experienced one of its most active dust storm seasons in the last 40 years with large dust plumes frequently advected over the adjacent Southern Ocean. We use meteorological records of dust activity, satellite ocean color, and aerosol optical depth data and dust transport modeling to investigate the transport and deposition of mineral dust from Australia over adjacent ocean regions and to correlate it with biological response in phytoplankton standing stock as measured by chlorophyll a concentration in 5 degree latitude bands from 40 degrees to 60 degrees S. Seasonal maxima in mean surface chlorophyll a of similar to 0.5 mg m(-3) were not achieved until late January 2003 or during February in the more southerly bands, which when compared with a 9 year satellite mean climatology suggests the phenology of the bloom in 2002-2003 was atypical. Contemporaneous field data on CO2 fugacity collected on transects between Tasmania and Antarctica show that significant atmospheric CO2 drawdown occurred as far south as 60 degrees S during February 2003. Our results provide strong evidence for a large-scale natural dust fertilization event in the Australian sector of the Southern Ocean and highlight the importance of dust-derived nutrients in the marine carbon cycle of the Southern Ocean.
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