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Biogeochemical iron budgets of the Southern Ocean south of Australia: Decoupling of iron and nutrient cycles in the subantarctic zone by the summertime supply
Author(s) -
Bowie Andrew R.,
Lannuzel Delphine,
Remenyi Tomas A.,
Wagener Thibaut,
Lam Phoebe J.,
Boyd Philip W.,
Guieu Cécile,
Townsend Ashley T.,
Trull Thomas W.
Publication year - 2009
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1029/2009gb003500
Subject(s) - biogeochemical cycle , aridification , oceanography , phytoplankton , chemical oceanography , environmental science , biogeochemistry , geotraces , westerlies , iron fertilization , nutrient , geology , climate change , seawater , environmental chemistry , ecology , chemistry , microorganism , paleontology , microbial biodegradation , bacteria , biology
Climate change is projected to significantly alter the delivery (stratification, boundary currents, aridification of landmasses, glacial melt) of iron to the Southern Ocean. We report the most comprehensive suite of biogeochemical iron budgets to date for three contrasting sites in subantarctic and polar frontal waters south of Australia. Distinct regional environments were responsible for differences in the mode and strength of iron supply mechanisms, with higher iron stocks and fluxes observed in surface northern subantarctic waters, where atmospheric iron fluxes were greater. Subsurface waters southeast of Tasmania were also enriched with particulate iron, manganese and aluminum, indicative of a strong advective source from shelf sediments. Subantarctic phytoplankton blooms are thus driven by both seasonal iron supply from southward advection of subtropical waters and by wind‐blown dust deposition, resulting in a strong decoupling of iron and nutrient cycles. We discuss the broader global significance our iron budgets for other ocean regions sensitive to climate‐driven changes in iron supply.