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Geochemical particle fluxes in the Southern Indian Ocean seasonal ice zone: Prydz Bay region, East Antarctica


Pilskaln, CH and Manganini, SJ and Trull, T and Armand, LK and Howard, W and Asper, VL and Massom, RA, Geochemical particle fluxes in the Southern Indian Ocean seasonal ice zone: Prydz Bay region, East Antarctica, Deep-Sea Research 1, 51, (2) pp. 307-332. ISSN 0967-0637 (2004) [Refereed Article]

DOI: doi:10.1016/j.dsr.2003.10.010


Time-series sediment traps were deployed between December 1998 and January 2000 and from March 2000 to February 2001 at two offshore Prydz Bay sites within the seasonal ice zone (SIZ) of the Southern Indian Ocean located between 62-63°S and 73-76°E to quantify seasonal biogeochemical particle fluxes. Samples were obtained from traps placed at 1400, 2400, and 3400m during the first deployment year (PZB-1) and from 3300m in the second deployment year (PZB-2). All geochemical export fluxes were highly seasonal with primary peaks occurring during the austral summer and relatively low fluxes prevailing through the winter months. Secondary flux peaks in mid-winter and in early spring were suggestive of small-scale, sea-ice break-up events and the spring retreat of seasonal ice, respectively. Biogenic silica represented over 70% (by weight) of the collected trap material and provided an annual opal export of 18gm-2 to 1km and 3-10gm-2 to 3km. POC fluxes supplied an annual export of approximately 1gm-2, equal to the estimated ocean-wide average. Elevated particulate Corg/Cinorg and Sibio/Cinorg molar ratios indicate a productive, diatom-dominated system, although consistently small fluxes of planktonic foraminifera and pteropod shells document a heterotrophic source of carbonate to deeper waters in the SIZ. The observation of high Sibio/C org ratios and the δ15N time-series data suggest enhanced rates of diatom-POC remineralization in the upper 1000m relative to bioSiO2. The occurrence in this region of a pronounced temperature minimum, associated with a strong pycnocline and subsurface particle maximum at 50-100m, may represent a zone where sinking, diatom-rich particulates temporarily accumulate and POC is remineralized. © 2003 Elsevier Ltd. All rights reserved.

Item Details

Item Type:Refereed Article
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Chemical oceanography
Objective Division:Environmental Management
Objective Group:Marine systems and management
Objective Field:Measurement and assessment of marine water quality and condition
UTAS Author:Trull, T (Professor Thomas Trull)
UTAS Author:Armand, LK (Dr Leanne Armand)
UTAS Author:Howard, W (Associate Professor William Howard)
UTAS Author:Massom, RA (Dr Robert Massom)
ID Code:32056
Year Published:2004
Web of Science® Times Cited:33
Deposited By:IASOS
Deposited On:2004-08-01
Last Modified:2005-06-06

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