ANALYSIS OF THECAMOEBIAN ASSEMBLAGES IN FALL CREEK FALLS STATE PARK

Thecamoebians, or testate amoebae, are microscopic, single-celled organisms that produce, either through agglutination or secretion, a mineralized shell. As these microorganisms prefer particular environmental conditions, and are relatively short-lived, they function as excellent indicator species. By analyzing the diversity, number, and types of thecamoebian species present in a particular environment, the health of that environment can be assessed. This research project uses samples containing thecamoebians collected from Fall Creek Falls State Park, a heavily forested, temperate environment and the largest State Park in Tennessee. As State Parks are important to both the economy of the state and the health of the local ecosystems overall, it is crucial that they be monitored and protected against potential environmental threats. Through this project, the health of three main bodies of water in the park – Fall Creek Falls Lake, Fall Creek Falls waterfall, and Cane Creek – was analyzed for environmental degradation. The assemblage composition was analyzed and the Shannon diversity index (SDI) was measured for each sample. Unfavorable environments have SDI values below 0.5 and healthy environments have SDI values above 2.5. Calculated SDI values for all three water bodies were between .998 and 1.788, indicating moderately healthy environments. Difflugia oblonga was the most numerous species in all samples, along with D. urceolata. These species are indicative of healthier environments. One sample collected from the lake was dominated by Centropyxis constricta with abundant Cucurbitella tricuspis. The other sample collected from the lake had abundant Centropyxis constricta and C. aculeata. Centropyxid species tolerate unfavorable environments better than other species and Cucurbitella tricuspis has been associated with nutrient enrichment. Analysis of assemblages and SDI measurements appears to indicate possible eutrophication in Fall Creek Falls Lake, though the other water bodies appear to have healthy assemblages. Further study is required to determine the source of the eutrophication.