Accurately quantifying net loads in tidal systems is difficult owing to the high variability in constituent concentrations over the vastly different time scales present in these systems. Perhaps most difficult is the measurement of fluxes over the tidal time scale. On this scale, the net export of the constituent is orders of magnitude less than the bulk exchange in either direction because of the vast quantities of water that are exchanged. Therefore, numerous measurements are required in a brief amount of time to accurately quantify constituent fluxes between a tidal wetland and its surrounding waters. These complications with sampling are exacerbated for mercury species because of the difficulties related to clean sampling and trace-level analysis. On approach to overcome these difficulties is to develop surrogates that may be measured and which may be used for interpolating and extrapolating from discrete measurements over a number of tidal cycles and a range of conditions.

The South Bay Salt Pond Restoration Project intends to restore many acres of impounded ponds to tidal exchange. There is evidence that tidal wetlands produce methyl mercury, the bioavailable form of mercury. This is a concern because sediment in the project area has relatively high concentrations of mercury and pond restoration is known to increase tidal prism and to scour sediment from adjacent sloughs. Although restoration is slated to begin, it is unknown (1) how much methyl mercury the restored ponds will export, (2) how much sediment and associated mercury will be scoured in adjacent sloughs, and (3) which management actions will best minimize the transport of these contaminants. The development of an instrumentation package that can be used to monitor in situ measurement of the transport of these contaminants would offer a valuable tool for the adaptive management of South Bay restoration efforts.