Mentor Marsh is the largest marsh within the Lake Erie basin (3.24 km2) and continues to act as important watershed entering the basin near the Grand River. Salt contamination of the marsh in the late 1950's and early 1960's led to a dramatic disruption in the marsh's ecosystem, resulting in die-offs of invertebrate, vertebrate and native plant species. Changes in the water quality also allowed for the invasion of exotic plant species, primarily the reed grass Phragmites australis.

We conducted a pilot study (1997-1999) to evaluate the effects of the re-routing of Blackbrook Creek, ten years after its completion. Preliminary tests of pH, conductivity, and ionic concentrations (Ca, Fe, Mg, Na, K, Si, Cl, SO4, and HCO3) indicate that the marsh has somewhat recovered from previous hypersaline conditions, but there are still significant areas where salinity becomes high, especially in the dry summer months. In addition, the marsh has been significantly impacted by the effects of enhanced eutrophication from the infilling of Phragmites, which has also affected the biodiversity of the flora in the marsh (Whipple and Park, 1997).

We are currently funded by Ohio Seagrant to conduct a study in the marsh determining its precise geological history and assessing the ecological impact of the salt contamination events and the effectiveness of the remediation efforts on the marsh's fauna and flora. By examining long and short term changes in the marsh, we will be able to to assess the natural vs. anthropogenic changes in the marsh, evaluating the long-term effects of the salt-contamination and subsequent remediation on this ecosystem.