Observing Bacterial Diversity in Glacial Till using 16S rRNA Sequencing

Abstract

Recent surveys of domestic wells in west central Minnesota have shown that the levels of arsenic in 50% of wells are higher than standards set by the EPA, creating a serious health risk for the surrounding populations. Investigations show that the arsenic contamination originates from naturally occurring arsenic in the surrounding glacial sediments that are part of the Des Moines Lobe; However, wells present in the Des Moines lobe are not universally contaminated with high levels of arsenic, suggesting that the process of contamination is controlled by other factors such as the presence of bacteria. This experiment aimed to observe if there are bacteria present in these soil samples that could play a role in arsenic contamination. To do this, DNA was extracted from core soil samples and the 16S rRNA gene was amplified using PCR. The PCR product was then cleaned and sent to a private lab to be sequenced using 454 pyrosequencing. Results are expected to indicate the presence of bacterial genera that have the ability to trigger arsenic contamination. These findings could further show the importance and scope of microbial populations on a geological level and could lead to avenues of bioremediation.