Ecology of Sulfur Cycling in Flooded Strip Mines

Habitat restoration efforts in reclaimed coal mining areas have included the flooding of shallow strip mines, creating patches of wetland with special chemical characteristics, like Lost Lake in Southern Illinois. Sulfur compounds released from the underlying coal lead to elevated sulfur concentrations in the water as compared to most other freshwater systems. These higher concentrations of sulfur compounds are expected to affect the species distribution, abundance and activity of the biota that inhabit strip mine wetlands. To determine whether sulfur cycling microorganisms affect and are affected by these wetlands, pertinent chemical parameters such as sulfate, sulfide, organic and inorganic carbon, and oxygen were measured, along with fluorescent in situ hybridization to determine relative cell abundances of sulfate reducing and sulfide oxidizing microorganisms. More significant differences for relative cell abundances were observed between oxic and anoxic samples than with the seasons. Seasonal differences were demonstrated with the chemistry and only in February 2013 for relative cell abundances. A negative correlation occurred between sulfide and sulfate concentrations. Positive correlations occurred between the relative abundance of green sulfur bacteria and oxygen concentration, and between the relative abundance of sulfate reducers and sulfide concentration