Abstract: Geophysical technologies are increasingly being used to non-invasively map and monitor the subsurface at spatiotemporal scales unobtainable with conventional, invasive methods of investigation. Geophysical research funded by the Meadowlands Environment Research Institute (MRRI) over the last five years has focused on applying geophysical technologies to the study of wetlands and monitoring subsurface processes in wetland soils. Established geophysical technologies (terrain conductivity, magnetometry) have been adopted to assess wetland degradation and the environmental impact of past land use history in Kearny Marsh. State-of-the-art resistivity imaging has been utilized to image solute transport and groundwater-surface water interaction from arrays of floating electrodes. Laboratory-scale studies have explored the sensitivity of novel electrical measurements to the concentration of iron and heavy metals in marsh soils, revealing a strong power-law relationship between iron concentration and electrical polarization. Recent laboratory research has focused on the use of electronic measurements (reactions on electrode surfaces) for monitoring sulfide as a proxy measure of anaerobic microbial activity in wetland soils. Current work is directed towards using electronic measurements to explore correlations between vegetation patterns and sulfide chemistry to test hypotheses that competition between native and invasive species in the NJ Meadowlands is regulated by sulfide toxicity.
