Topic: College of Sciences and Humanities

April 7, 2008

Nature, one of the world's leading scientific journals, published a study co-authored by a Ball State University professor in its March 13 issue.

Melody Bernot, an assistant professor of biology, co-authored the six-year study, "Stream denitrification across biomes and its response to anthropogenic nitrate loading." The study examined how streams filter nitrates, which are nitrogen-based pollutants, and how human activity affects their ability to filter them. Denitrification is the removal of nitrates from streams by microbes.

Bernot became interested in denitrification through her interest in biology and chemistry.

"I've always wanted something that combined field with the lab," said Bernot, who came to Ball State in fall 2007. "I spend half my time with waders and half my time with beakers."

Bernot was part of a team of 32 scientists from across the U.S. headed by Pat Mulholland, a researcher with the Oak Ridge National Laboratory and the University of Tennessee. Funded by a grant from the National Science Foundation, the study examined 72 streams in the U.S., including Puerto Rico. The scientists put small amounts of the nitrate N-15 in the streams and studied how far downstream it got before disappearing.

The first phase of the study found that streams are important for removing nitrates from other bodies of water as microbes such as bacteria, algae and fungi filtered the nitrates before they reach lakes and coastal waters. The second phase of the study found that entire river networks are important in the removal of pollution, but agricultural practices are overloading streams with nitrates and limiting their ability to remove them. This increases the risk of noxious algae blooms that deplete oxygen and lead to "dead zones" such as the one in the Gulf of Mexico.

By Alaric DeArment