Honors Program Theses


Open Access Honors Program Thesis

First Advisor

Edward J. Brown


An overabundance of phosphorus, primarily due to agricultural run off, is the source of increases in unwanted algae in Iowa's surface waters. Oxidized iron found in mine tailings will sequester phosphorus in sediments and prevent it from entering surface waters. Therefore, adding mine tailings to wetlands is a cheap and easy way to eliminate phosphorus pollution. This phosphorus removal process is enhanced by a microbial component that biochemically solubilizes iron tailings which allows them to efficiently react with free phosphorus in the water. The purpose of this project was to characterize the microbial component in this process. Ferric citrate medium was made and sealed in anaerobic bottles to enrich for and isolate iron-reducing bacteria from sediment samples enriched with iron. Multiple transfers and relatively long (three week) incubation periods were necessary to ensure pure cultures were isolated. Bacteria were then harvested from enrichments and DNA was obtained. The 16s rRNA gene was amplified using PCR and primers specific for metal reducing bacteria, and then the product was sequenced using the DCTS Quick Start Kit. Final sequencing was confirmed by Laragen Inc. (Los Angeles, CA). The sequence obtained from the isolate was compared to known 16s sequences in Genbank and shown to be 99% identical Desulfotomaculum sp. The results demonstrate that aquatic sediments supplemented with iron mine tailings sequester phosphorus and harbor bacteria known to reduce iron.

Year of Submission



Department of Biology

University Honors Designation

A thesis submitted in partial fulfillment of the requirements for the designation University Honors


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Date Original


Object Description

1 PDF file (ii, 30 pages)