Evaluation of Benthic Diatoms as Water Quality Indicators in the Blackbird Creek Watershed, Delaware

Benthic diatoms have been used as water quality indicators in freshwater systems throughout the world. They are present in almost every aquatic habitat and due to their high growth rates and rapid response to changes in water chemistry, diatoms are ideal biological indicators. The goal of this study is to evaluate the use of benthic diatoms as water quality indicators of the Blackbird Creek watershed in relation to land use. Sediment samples were collected from the selected sites in the Blackbird Creek Watershed and DNA was extracted from sediments using methods described in Coyne et al. (2001). Water samples were collected to analyze and record nutrients and water quality parameters of each study site. DNA was extracted from the samples and analyzed using denaturing gradient gel electrophoresis (DGGE) to produce a banding pattern or “fingerprint” of the microbial community. Diatom diversity was evaluated by comparing the patterns generated by DGGE using statistical analyses. Sample DNA run on a DGGE gel has already shown a strong diatom species presence, but further analysis is required. The information gathered during this study will hopefully aid in identifying ecological problems such as eutrophication in Blackbird Creek. The knowledge gained in this study will be used to obtain a better understanding of the diatom communities present, determine the effects of land use on water quality, and provide strong information to aid the improvement of land management practices.