USING THECAMOEBIAN POPULATIONS TO EVALUATE HISTORICAL WATER QUALITY IN TODDS LAKE IN MURFREESBORO, TENNESSEE

Water quality is and will continue to be an important environmental concern. Todds Lake is a small freshwater, artificial reservoir in Murfreesboro, Tennessee that was created in the 1930s by damming a wetland. Murfreesboro has experienced tremendous growth and rapid urbanization in the past decade with the population of the city increasing 50.5% from 2000 to 2010. Todds Lake is located in the Stones River Watershed and is fed by Black Fox Spring, which travels through several subdivisions receiving runoff from lawns and driveways before ending in Todds Lake. The lake is also surrounded by urban development such as additional subdivisions, a strip mall and a gas station and may be receiving runoff from those areas that could be negatively affecting the water quality within the lake. Thecamoebians are benthic testate amoebae that have been used in multiple studies in North America and Europe as indicators of pollution and water quality in lacustrine environments. Analysis of thecamoebian populations from sediment samples collected in Todds Lake in recent years indicates that the lake is a stressed eutrophic environment with low diversity assemblages and abundant Centropyxis aculeata observed in the samples. The shells of thecamoebians preserve easily so these organisms can yield historical data on water quality. The fossilization potential of thecamoebians gives them an advantage over other freshwater micro- and macroinvertebrates. This study will compare populations of thecamoebians from sediment samples in Todds Lake with those found in samples taken from a sediment core to determine if there have been changes in the ecological condition of the lake and wetland over the last century.