Can we use the Dynamic Mercury Cycling Model to explore mechanistic processes in Hg cycling in prairie lakes?

English Abstract:

Mercury (Hg) is emitted via industrial activities and deposited to landscapes as wet and dry deposition. Even the most remote areas receive Hg via atmospheric deposition, but studies focusing on Hg cycling have typically concentrated on boreal aquatic ecosystems. Therefore, Hg cycling in many aquatic systems, such as prairie systems, is understudied. Furthermore, there are major physical and chemical differences between boreal and prairie lakes, such as disparities in pH, salinity, and sulfate and sulfide concentrations, which may result in differences in Hg cycling. The objective of this study is to employ the Dynamic Mercury Cycling Model (D-MCM) to explore mechanisms underpinning differences in Hg cycling in prairie lakes compared to boreal lakes. The D-MCM is a time-dependent, mechanistic simulation model that predicts Hg cycling and bioaccumulation in aquatic systems. It was developed using data from boreal lakes and has been shown to accurately predict Hg cycling in the environment. The D-MCM will be used to test for differences in Hg cycling by inputting various environmental parameters, such as temperature, ion and Hg concentrations, hydrological data, community structure, and sediment properties, for prairie lakes. The resulting model prediction will be compared with pre-measured values of Hg concentrations in sports fish. Scenarios that differ will then be analyzed with inverse modeling techniques that indicate inaccurate model algorithms. Since the model has been proven to work in a range of boreal systems, incorrect algorithms may indicate differences in Hg cycling in prairie compared to boreal environments.