HR: 13:40h
AN: B13F-01 INVITED    [Abstracts]
TI: Redox Transformations of Mercury in Wetlands
AU: * Amyot, M
EM: m.amyot@umontreal.ca
AB: Wetlands are valued for their high biodiversity and for their ecosystem services. However, we still have a poor understanding of their role in the redox transformation of contaminants such as mercury. We first propose a brief overview of past studies conducted on wetlands from different latitudes. In most instances, photochemical processes are determinant in the upper portion of the water column. At the sediment/water interface, evidence is currently supporting a significant contribution of bacterial communities, as promoters of Hg(II) reduction, particularly in the presence of anoxia. A multi-year study was recently conducted on Hg redox cycling in a fluvial wetland of the St. Lawrence River, where wetland restoration could have unintended consequences. In addition to photochemistry and bacterial reduction, Hg redox cycling was affected by epiphytes living on macrophytes, through adsorption/absorption processes. Redox studies such as this one have been historically seen as having implication for water/air flux studies, since Hg(0) is volatile. We here also discuss the potential bioavailability of Hg(0) towards bacteria. An emerging axis of our wetland research effort deals with beaver dams, which are in expansion and shown to produce high levels of methylHg
DE: 0412 Biogeochemical kinetics and reaction modeling (0414, 0793, 1615, 4805, 4912)
DE: 0438 Diel, seasonal, and annual cycles (4227)
DE: 0461 Metals
DE: 0497 Wetlands (1890)
DE: 4802 Anoxic environments (0404, 1803, 4834, 4902)
SC: Biogeosciences [B]
MN: 2007 Fall Meeting