Subantarctic zone oceanography - SAZ Project 1997-1998 - Arsenic Data
Oceanographic processes in the subantarctic region contribute crucially to the physical and biogeochemical aspects of the global climate system. To explore and quantify these contributions, the Antarctic Cooperative Research Centre (CRC) organised the SAZ Project, a multidisciplinary, multiship investigation carried out south of Australia in the austral summer of 1997-1998.
Taken from the ... abstracts of the referenced papers:
The development of a semi-automated batch HG-AFS method for the shipboard determination of As(III), As(V),MMA and DMA is described. Procedures in the analytical sequence including addition of NaBH4 to samples, cooling and heating the U-trap used for pre-concentration and separation of the arsines, and logging the AFS output are automated. Overall control of the automated tasks into a logical analytical sequence is achieved using a commercially available data acquisition and control package, workbenchmac(TM). Further modifications required for the method to be adapted to shipboard use, including the
use of a hydrogen generator, are also detailed.
This method shows a number of advantages over a previously reported manual HG-AFS method including, shorter sample throughput time, increased precision and most significantly, ease of use under shipboard conditions.
The semi-automated method was operated on the RSV Aurora Australis during a Southern Ocean voyage in March 1998. Arsenic measurements from a surface transect between 42 and 55 degrees S along 141 degrees 30 minutes E, are presented. Application of the method to more routine laboratory use is also discussed.
Distribution of the arsenic species total inorganic arsenic [As(V+III)], arsenite [As(III)], monomethyl arsenic(MMA), andd dimethyl arsenic (DMA) was studied in the Subantarctic Zone (SAZ) of the Southern Ocean, south of Australia, during the austral autumn (March 1998). As (V) was the dominant arsenic species in both vertical profiles and surface waters along the meridional transect 42-55 degrees S, 141 degrees 30' E. It was also the only species observed at depths greater than 600 m. Concentrations of the reduced arsenic species (As(III), MMA, and DMA) were low in these waters compared with other oceanic sites with similar concentrations of chlorophyl a. As(III) concentrations could not be reliably quantified at any sites (less than 0.04 nM). The greatest conversion of As(V) to "biological" species was found at the
surface in the Subtropical Convergence Zone(2.5%) and decreased heading southward to 1% in the Polar Front (PF). While the decline in methyl arsenic concentrations was broadly associated with water temperature and measures of biological production, slightly different trends were found in the SAZ and PF. North of the Subantarctic Front (SAF), methyl arsenic concentrations were well correlated with water temperature, while south of the front, no such relation existed. In addition, the ratio DMA/MMA increased south of the SAF, associated with a change in the microalgal community composition. Low water temperature, phosphate replete conditions, and low biological productivity in the Southern Ocean all contribute to the concentrations of biologically produced arsenic species in this region being among the lowest reported for oceanic waters.
(Click for Interactive Map)
This data set description is a member of a collection. The
collection is described in
See the referenced papers for more information.
Copies of the referenced publications are available for download from the provided URL to AAD staff only.
Data Set Progress
+61 3 6226 2174
+61 3 6226 2858
Alison.Featherstone at utas.edu.au
School of Chemistry
GPO Box 252-75
University of Tasmania
Province or State:
+61 3 6226 2988
+61 3 6226 2973
tom.trull at utas.edu.au
GPO BOX 252-80
Antarctic CRC University of Tasmania
Province or State:
+61 3 6232 3244
+61 3 6232 3351
dave.connell at aad.gov.au
Australian Antarctic Division
203 Channel Highway
Province or State:
Featherstone A.M., Boult P.R., O'Grady B.V., Butler E.C.V. (2000), A shipboard method for arsenic speciation using semi-automated hydride generation atomic fluorescence spectroscopy, Analytica Chimica Acta, 409, 215-226
Featherstone A.M., Butler E.C.V., O'Grady B.V.O. (2001), Meridional distribution of arsenic species in the subantarctic zone of the Southern Ocean, south of Australia, Journal of Geophysical Research (Oceans), 106, C12, 31657-31668
Creation and Review Dates
DIF Creation Date:
Last DIF Revision Date: