Atmospheric deposition in southeastern North Carolina and its impact on the Cape Fear River estuary

UNCW Author/Contributor (non-UNCW co-authors, if there are any, appear on document)
Michael S. Long (Creator)
The University of North Carolina Wilmington (UNCW )
Web Site:
Doug Gamble

Abstract: Concentrations of NHx, NO3 -, free amino acids, total and organic nitrogen, and inorganic anions were determined for 78 rain events between September 1, 2002 and August 31, 2003, on the campus of the University of North Carolina at Wilmington in southeastern North Carolina. The majority of N in Wilmington rain (78%) is inorganic, occurring as NO3 - and NHx in approximately equal proportions. Free amino acids make up a small portion of ON (11%). Correlation analysis and back trajectory analysis indicate that regional sources, rather than local emissions, determine the concentrations of inorganic N in UNCW rainwater and particle dry deposition. NO3 - concentration in rainwater at UNCW has decreased from 1990 to the present while wet deposition increased due to increased rainfall and possibly increased emissions from growing population and expanding industry in North Carolina. Wet and dry deposition of NHx are respectively 53% and 26% higher than a decade ago reflecting an increase in regional and possibly local emissions. Similar temporal patterns in are seen at UNCW and the NADP monitored sites with the greatest increase in Clinton, NC, where NHx concentrations and depositions have increased 58% and 107% respectively. Concentrations of H+ and major N analytes, with the exception of ON, vary significantly as a function of air mass origin with major increases in analytes correlating with locations of known anthropogenic sources. Seasonal and diurnal influences have a significant impact on the concentrations of H+ and N analytes in UNCW rainwater with significant concentration maximums in the spring and significantly lower concentrations from 6:00AM to 10:00PM. Direct atmospheric deposition is not a major source of bioavailable nitrogen to the Cape Fear River Estuary. The average total daily NHx and NO3 - dry depositions were small in comparison to their total amounts in the CFRE. Wet depositions of NHx reached 20% for a single event with an average per event deposition equivalent to 1.3% of NHx in the CFRE. Dry deposition accounts for 17% of inorganic N deposition to the CFRE; though it is possibly underestimated in this study.

Additional Information

A Thesis Submitted to the University of North Carolina at Wilmington in Partial Fulfillment Of the Requirements for the Degree of Master of Science
Language: English
Date: 2009
Atmospheric deposition--North Carolina--Cape Fear River Estuary, Rain-water (Water-supply)--Analysis, Rain-water (Water-supply)--North Carolina--Wilmington
Atmospheric deposition -- North Carolina -- Cape Fear River Estuary
Rain-water (Water-supply) -- Analysis
Rain-water (Water-supply) -- North Carolina -- Wilmington

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