It is well recognized that the chemical forms of mercury in the water column and sediments are intimately related to its overall effects on living organisms. Interactions of mercury and dissolved organic matter may play an important role in controlling both the availability of mercury for uptake by living organisms, and the types of chemical reactions that can occur with mercury. For instance, the association of mercury with dissolved organic carbon (DOC) has been proposed as a primary mechanism for the transport of mercury in aquatic systems. This association has been proposed on the basis of a strong correlation between dissolved mercury and DOC concentrations in ground, lake and stream waters. Little is known, however, about how mercury interacts with DOC or how strong these interactions are. It does appear, however, that interactions with DOC may be significant in controlling the transport and bioavailability of mercury. The important questions to be addressed are: 1) By what mechanisms and how strongly does mercury interact with DOC, and 2) How do these interactions control the effects that mercury has on living organisms. The goal of our current research is to provide information about the interactions of mercury and dissolved organic matter that will better define this important, albeit, poorly understood process. Ultimately, this research will lead to a more complete model of mercury behavior in the environment. Our research will focus on the effect of DOC on the transport and reactivity of mercury through a combined field and laboratory study. The underlying hypothesis of this research is that the chemistry and structural characteristics of organic matter in the Everglades have a strong influence on the processes that control mercury cycling in the environment.

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