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Alexandria Hounshell, Marine Sciences Graduate student has been awarded the Graduate Education Advancement Board Impact Award for her research on algal growth in the Neuse River.

Tracking Elusive Nutrient Sources for Algal Growth in the Neuse River Estuary

North Carolina’s lakes, rivers and estuaries have long experienced negative impacts of nutrient over-enrichment, impacts including fish kills and harmful algal blooms. The Neuse River Estuary has exhibited symptoms of nutrient over-enrichment since the mid-1980s. Legislation was enacted to reduce loading of nutrients such as nitrogen and phosphorus from watershed sources; these nutrients act as fertilizer for algae living in the estuary. While inorganic nitrogen has decreased, the problem of over-enrichment persists. Doctoral student Alexandria Hounshell analyzed documented increases in organic nitrogen in the Neuse River Estuary and applied innovative measurement techniques to determine what specific organic nitrogen sources could cause the continued impacts of nutrient over-enrichment.

Organic nitrogen is a complex mixture of molecules that are not easily characterized. Hounshell’s analysis used a technique that draws on the ability of certain organic nitrogen molecules to absorb light and re-emit that light as fluorescence, to better characterize these molecules. She tested which watershed sources of organic nitrogen (chicken and turkey litter waste, river organic nitrogen and wastewater treatment plant runoff) can be used by algae as a nitrogen-based source for growth. Results indicate that chicken litter waste may contribute to excess algal growth still observed in the estuary.

Hounshell and colleagues have shared their results with N.C. Sea Grant, the Water Resources Research Institute of the UNC System and other statewide organizations. Her research has also informed lesson plans for N.C. K-12 students.

“Alex’s dissertation work has highly significant applications and implications for how we manage land-based nitrogen in the future, including in North Carolina,” said adviser Hans Paerl, Ph.D.


Credit to UNC Graduate School:

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