USING THECAMOEBIANS AS INDICATORS OF LAND USE CHANGES IN TENNESSEE AND VIRGINIA

Thecamoebians, testate amoebae, have been used increasingly as proxies for water quality and land use changes in North America and Europe, although little work has been done using these microscopic organisms in the southeastern United States. Sediment samples collected from lakes and wetlands in Tennessee and Virginia have proven that these organisms are highly sensitive to changes in environments and are useful as pollution indicators in both lowland and upland environments. Thecamoebians have mineralized shells and preserve well in the fossil record. Sediment cores have been collected from Todds Lake in Tennessee and Wetlands Estonoa in Virginia to determine the efficacy of using thecamoebians as indicators of land use changes in different environments in the southeast. Todds Lake is a lowland lake. It is a small freshwater, artificial reservoir that was created by damming a wetland in the 1930s. It is located in Murfreesboro, which is a rapidly growing city and the population has increased by 50.5% since 2000. The land surrounding Todds Lake has become increasingly urbanized and now includes an elementary school, gas station, strip mall and several subdivisions. Wetlands Estonoa is located in the Appalachian town of Saint Paul. In the early 1900s the wetland began as a wet cornfield. It was dammed and became the town swimming hole until the mid-1900s when it began to be used as an illegal trash dump. It is now a reclaimed wetland being preserved by high school students. Several sediment cores have been collected from both locations and dating indicates that the oldest core samples pre-date the transformation of the areas. Preliminary examination of the core samples from both sites shows changes in community composition that can be correlated with land use changes in the last 100 years, including an increase in the relative abundance of Cyclopyxis kahli in Todds Lake. This species is thought to live in soils and could indicate increased soil erosion related to urban development around the lake.