Background
Project Goals
Project History
Current Research
Personnel
Collaborators
Publications
Links

Atmospheric Deposition









Background: Atmospheric Deposition of Nitrogen

The atmospheric deposition of nitrogen (AD-N) can play a key role in the "new" nitrogen budgets of coastal ecosystems. In nitrogen limited systems, such as the Neuse River Estuary, North Carolina, N inputs from the atmosphere, in the form of wet and dry deposition of ammonia, nitrate and organic nitrogen, can stimulate phytoplankton production and change phytoplankton community structure and composition, which in turn can affect water quality in general (hypoxia/anoxia, harmful or nuisance algal blooms, etc.).

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Project Goals

The overall goal of the Atmospheric Nitrogen Deposition Project is to understand the role of AD-N in the nitrogen budgets of coastal ecosystems, including spatiotemporal variability of deposition, sources of AD-N, ecosystem response to atmospheric nitrogen inputs, the relative importance of AD-N compared to other N sources, watershed processing of AD-N and the role of direct versus indirect nitrogen deposition.

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Project History

Although atmospheric nitrogen, in the form of NOx, has been recognized as a key component of acid rain since the early 1970's, nitrogen's role as an nutrient input to coastal waters was not recognized until much later.  Scientists at UNC-IMS, under the direction of Hans Paerl, first began studying precipitation chemistry in coastal North Carolina in the early 1980's during offshore cruises; during this research the nitrogen, in the form of NO3- and NH4+, in precipitation was demonstrated to stimulate phytoplankton production in bioassays. Later, in bioassay experiments with near-shore and estuarine waters, organic nitrogen in precipitation was also shown to stimulate primary production.
Precipitation chemistry has been measured at UNC-IMS since 1988 and on a regular "event" sampling schedule since 1991. In the summer of 1996, a sampling transect of precipitation collectors was established in the Neuse River watershed. Today, this array of samplers includes 6 locations run by UNC-IMS and 2 national network sites (see map).

 
 

In 1999, continuous ambient gas and aerosol nitrogen sampling was initiated at UNC-IMS via annular denuder technology. This sampling is an important first step in quantifying the contribution of dry deposition (particles and gases) of nitrogen to coastal systems.

Dr. Paerl and Dr. Whitall have worked closely with North Carolina Department of Environment and Natural Resources in evaluating the need for regulations to address atmospheric NH3 emissions as part of the mandated 30% nitrogen reduction in loadings to the Neuse. Regulations regarding NH3 emissions from intensive animal operations are currently in the draft phase.

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Current Research

New Bern Collector
Weekly precipitation sampling of 5 collectors (pictured below) in Neuse River Basin (see map), plus event sampling of precipitation at UNC-IMS in Morehead City.  Precipitation samples are analyzed for NH4+, NO3-, TKN and stable nitrogen isotopes.

 
“Event” precipitation sampler at IMS
 "Event" precipitation sampling for NH4+ , NO3-, TKN and stable nitrogen isotopes at UNC-IMS in Morehead City. Co-located with this sampler is a meteorological station.

Four days per week of continuous integrated air sampling for ambient gaseous and particulate concentrations via annular denuder technology at UNC-IMS in Morehead City.
 
 

UNC-IMS also works in connection with the U.S. Environmental Protection Agency and the National Atmospheric Deposition Program/National Trends Network to operate the Beaufort NADP/CASTNet monitoring station.  This station monitors wet precipitation chemistry, ambient N concentrations (filter pack technology), ambient ozone and meteorological parameters.
 

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Personnel

 

Dr. Hans Paerl  Project Director 
Dr. David Whitall Post-doctoral Research Assoc.
Brad Hendrickson Project Technician
Nathan Hall Site Operator, NADP/CASTNet Site 

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Collaborators

Dr. Robin Dennis, U.S. Environmental Protection Agency/NOAA

Dr. Marilyn Fogel, Carnegie Institution of Washington

Dr. George Murray, NC Dept. of Environment and Natural Resources

Dr. Wayne Robarge, North Carolina State University

Dr. Joe Rudek, Environmental Defense

Dr. Bill Showers, North Carolina State University

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Publications

Whitall, D.R. and H.W. Paerl. 

Annual flux and spatiotemporal variability of atmospheric nitrogen deposition to the Neuse River Watershed, North Carolina. Submitted to Journal of Environmental Quality.

Paerl, H.W., R.L. Dennis and D.R. Whitall. 

Atmospheric deposition of nitrogen: implications for nutrient over-enrichment of coastal waters. Submitted to Estuaries.

Whitall D.R., W.J. Showers and H.W. Paerl.

Source identification of atmospherically deposited ammonium in eastern North Carolina via stable nitrogen isotope techniques. (in prep)

Whitall, D.R., W.P. Robarge, and H.W. Paerl.

Comparison of atmospheric concentration of ammonia and ammonium aerosols between three sites in eastern North Carolina. (in prep).

Whitall, D.R. 2000.

Atmospheric Nitrogen Deposition to the Neuse River Watershed:Fluxes,Sources and Spatiotemporal Variability. Doctoral Dissertation. University of North Carolina at Chapel Hill.

Whitall, D.R. B.L. Peierls and H.W. Paerl. 1999.

Atmospheric nitrogen deposition to the Neuse River Basin: Annual budget and spatiotemporal variability. In: Proceedings of Workshop on Atmospheric Nitrogen Compounds II: Emissions, Transport, Transformation, Deposition and Assessment. V.P. Aneja, G. Murray and J. Southerland (eds). Chapel Hill, NC June 1999.

Paerl, H.W. and D.R. Whitall. 1999.

Anthropogenically-derived nitrogen deposition, marine eutrophication and harmful algal bloom expansion: is there a link? Ambio 28: 307-311.

Paerl, H., W. Showers, D. Whitall and J. Karr. 1999. 

Stable Nitrogen IsotopicTracers(d15 N) of Excess Nitrogen Sources to the Neuse River Estuary. North Carolina, Department of Environment and Natural Resources, Division of Marine Fisheries Final Report.

Whitall, D., J. Rudek, W. Showers and H. Paerl. 1999. 

Quantification of Fluxes and Sources of Atmospherically-Deposited Nitrogen (AD-N) in Eastern North Carolina. Environmental Defense Fund Final Report.

Paerl, H.W. and D.R. Whitall. 1999.

Anthropogenically-derived atmospheric nitrogendeposition, marine eutrophication and harmful algal bloom expansion: is there a link? Ambio 28: 307-311.

Paerl, H.W., W.R. Boynton, R.L. Dennis, C.T. Driscoll, H.S. Greening, J.N. Kremer, N.N. Rabalais, and S.P. Seitzinger. 1999. 

Atmospheric deposition of nitrogen in coastal waters: biogeochemical and ecological implications. IN: Nitrogen in Coastal Waters. R. Valigua (ed).

Paerl, H.W. 1997.

Coastal eutrophication and harmful algal blooms: importance of atmospheric deposition and groundwater as “new” nitrogen and   other nutrient sources. Limnology and Oceanography 42: 1154-1165.

Peierls, B.L and H.W. Paerl. 1997.

Bioavailability of atmospheric organic nitrogendeposition to coastal phytoplankton. Limnology and Oceanography 42: 1819-1823.

Paerl, H.W. 1995.

Coastal eutrophication in relation to atmospheric nitrogen deposition:current perspectives. Ophelia 41:237-259.

 
Paerl , H.W and M.L. Fogel. 1994. 

Isotopic characterization of atmospheric nitrogen inputs as sources of enhanced primary production in coastal Atlantic Ocean waters. Marine Biology 119:635-645.

 
Paerl, H.W., M.L. Fogel and P.W. Bates. 1993. 

Microbial Ecology. R. Guerrero and C. Pedros-Alio eds. Spanish Society for Microbiology.


Paerl, H.W. 1985.

Enhancement of marine primary production by nitrogen-enriched acid rain. Nature 316:747?749.

 
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Links to other Atmospheric Deposition Sites

National Atmospheric Deposition Program (NADP/NTN)

U.S. EPA Clean Air Status and Trends Network (CASTNet)

NOAA Air Resources Laboratory Main Page 

NOAA ARL Atmospheric Integrated Monitoring Network (AIRMon) 

NOAA ARL HYSPLIT Model 

Lakes Environmental EPA Air Quality Models 

U.S. EPA Air Quality Screening Model (SCREEN3) 

Scorecard Nationwide Information System on Pollution (Environmental Defense)
 

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