Sulfur reduction and oxidation processes, from wetland scale to micro scale, in an inland acid sulfate soil of the lower Murray-Darling River floodplains, Australia  

Authors / CoAuthors

Wallace, L. | McPhail, D.C. | Fitzpatrick, R.W. | Welch, S. | Kirste, D. | Beavie, S. | Lamontagne, S.

Abstract

Inland acid sulfate soil systems have recently been found to be ubiquitous throughout wetlands of the Murray-Darling River floodplains, Australia, associated with high water levels and salinity. Coastal acid sulfate soil systems have been shown to cause significant landscape, water and infrastructure degradation. However, little is known about the driving processes of sulfide accumulation and subsequent oxidation within recent inland sulfidic wetlands; an essential component of acid sulfate soil management. Several recent studies have focused on inland sulfide formation or oxidation but none have conseptualised in detail the driving processes of sulfur from formation to oxidation. This study has identified and integrated the processes that control the storage and dynamics of sulfur, under reducing and oxidising conditions, from the wetland to micro scales, in the Loveday Basin inland acid sulfate soil system of the lower Murray-Darling River floodplains in South Australia. The integration of the above findings of sulfur oxidation and reduction, from wetland scale to micro scale, allows for a conceptual understanding of sulfur storage and dynamics in inland acid sulfate soils of the lower Murray-Darling River floodplains. The results of this study show the Loveday Basin has undergone three distinct phases over time. Pre-1972, prior to the regulation of basin waters, the sediments underwent regular wetting and drying cycles with no significant accumulation of sulfides. From 1970 to 2000 water regulation and partial disconnection from the river channel resulted in the accumulation of sulfide-rich wetland clays. Post-2000 partial draining of sulfidic sediments has produced extensive sulfide oxidation and complex, but predictable, physical and chemical heterogeneity. These three phases are principally controlled by the prevailing water regime. The integration of results in this detailed study shows how the complexity of chemical processes at the micro scale controls landscape evolution at the wetland scale.

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nonGeographicDataset

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73973

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• External PublicationAbstract

( Theme )

• marine

Australian and New Zealand Standard Research Classification (ANZSRC)

• Earth Sciences

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2012-03-29T00:00:00

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