Title

Quantifying alkalinity generating processes in a tidally remediating acidic wetland

Document Type

Article

Publication details

Johnston, SG, Keene, AF, Burton, ED, Bush, RT & Sullivan, LA 2012, 'Quantifying alkalinity generating processes in a tidally remediating acidic wetland', Chemical Geology, vol. 304/305, pp. 106-116.

Publisher version available from: http://dx.doi.org/10.1016/j.chemgeo.2012.02.008

Peer Reviewed

Peer-Reviewed

Abstract

Lime-assisted tidal exchange (LATE) is a new remediation technique that is demonstrably effective at decreasing acidity in coastal acid sulfate soils (CASS). However, the relative magnitude of the major in situ alkalinity generating processes and external alkalinity inputs that dominate neutralization of acidity during LATE have not been quantified. Here, we combine investigations of porewater and solid-phase geochemistry from a remediating CASS wetland to derive first-order estimates of alkalinity generating processes and inputs after 6 years of LATE. Quantified inputs include: marine derived HCO3− from tidal exchange; hydrated lime additions; and in situ alkalinity from anaerobic metabolism of organic carbon coupled with reduction of iron and sulfate. A progressive increase in tidal inundation led to the development of significant relationships (