UNIVERSITY PARK, Pa. — Andrew Shaughnessy, a doctoral student studying geosciences in Penn State’s College of Earth and Mineral Sciences (EMS), was awarded a 2019 Graduate Research Fellowship from the National Science Foundation. He is one of seven EMS students and 24 Penn State students to receive the honor.

The fellowship supports Shaughnessy’s research on the effects of agriculture on bedrock weathering.

In agricultural areas, excessive use of fertilizer may create a surplus of nutrients — such as nitrate — in surface water and groundwater. The link between agricultural fertilizers and algal blooms in surface waters is well known, but the influence on bedrock weathering processes in groundwater has not been fully investigated.

Shaughnessy is exploring how the influx of nitrate can enhance bedrock weathering processes. Though chemical reactions with water and oxygen, the iron and sulfur in pyrite can produce sulfuric acid, causing bedrock weathering. This is a naturally occurring process, but with the addition of nitrate to the groundwater, which provides another oxygen source, this process may be altered.

This reaction may have beneficial health implications. High levels of nitrates in drinking water can be harmful, especially for infants. Since the reaction with pyrite can remove nitrate from groundwater, it can be advantageous for human health.

“The reaction between pyrite and nitrate can naturally attenuate some of the pollution from agricultural activity,” Shaughnessy said.

Shaughnessy’s research also has implications for developing best management practices.

“Depending on the concentration of pyrite in the bedrock, our research could provide an appropriate strategy for individual farmers’ land management methods,” Shaughnessy said. “For example, a catchment, or drainage basin, with less pyrite in the bedrock may require improved management of excess nitrate. Farmers in catchments containing more bedrock pyrite, however, may need to prioritize other practices.”  

Shaughnessy’s adviser is Susan Brantley, distinguished professor of geosciences and director of Penn State’s Earth and Environmental Systems Institute.

“Andrew is a terrific student who joined us from St. Louis University and has become one of the most prolific water-samplers and data-analyzers in our geochemistry team,” said Brantley.

Shaughnessy was pleased to be selected from many applicants for this competitive fellowship.

“I was very happy to receive the fellowship and felt it was a great honor to be selected,” said Shaughnessy, whose future goal is to become a professor and continue his research on human-environment interaction.

The NSF Graduate Research Fellowship Program recognizes and supports outstanding graduate students in NSF-supported science, technology, engineering and mathematics disciplines who are pursuing research-based master's and doctoral degrees at accredited institutions in the United States. Approximately 12,000 students apply annually and 2,000 receive awards.