The influence of climate on average nitrogen export from large watersheds in the Northeastern United States

  • R. W. Howarth
  • D. P. Swaney
  • E. W. Boyer
  • R. Marino
  • N. Jaworski
  • C. Goodale


The flux of nitrogen in large rivers in North America and Europe is well explained as a function of the net anthropogenic inputs of nitrogen to the landscape, with on average 20 to 25% of these inputs exported in rivers and 75 to 80% of the nitrogen retained or denitrified in the landscape. Here, we use data for average riverine nitrogen fluxes and anthropogenic inputs of nitrogen over a 6-year period (1988–1993) for 16 major watersheds in the northeastern United States to examine if there is also a climatic influence on nitrogen fluxes in rivers. Previous studies have shown that for any given river, nitrogen fluxes are greater in years with higher discharge, but this can be interpreted as storage of nitrogen in the landscape during dry years and flushing of this stored nitrogen during wet years. Our analyses demonstrate that there is also a longer-term steady-state influence of climate on riverine nitrogen fluxes. Those watersheds that have higher precipitation and higher discharge export a greater fraction of the net anthropogenic inputs of nitrogen. This fractional export ranges from 10 to 15% of the nitrogen inputs in drier watersheds in the northeastern United States to over 35% in the wetter watersheds. We believe this is driven by lower rates of denitrification in the wetter watersheds, perhaps because shorter water residence times do not allow for as much denitrification in riparian wetlands and low-order streams. Using mean projections for the consequences of future climate change on precipitation and discharge, we estimate that nitrogen fluxes in the Susquehanna River to Chesapeake Bay may increase by 3 to 17% by 2030 and by 16 to 65% by 2095 due to greater fractional delivery of net anthropogenic nitrogen inputs as precipitation and discharge increase. Although these projections are highly uncertain, they suggest a need to better consider the influence of climate on riverine nitrogen fluxes as part of management efforts to control coastal nitrogen pollution.

Key words

Nitrogen Nutrients Nitrogen flux Nitrogen pollution Denitrification Climate change Net anthropogenic nitrogen inputs NANI Watersheds River River basin 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Aber J., McDowell W., Nadelhoffer K., Magill A., Berntson G., Kamakea M., McNulty S., Currie W., Rustad L. and Fernandez I. 1998. Nitrogen saturation is temperate forest ecosystems. BioScience 48: 921–934.CrossRefGoogle Scholar
  2. Aber J., Goodale C., Ollinger S.V., Smith M., Magill A.H., Martin M.E., Hallett R. and Stoddard J.L. 2003. Is nitrogen deposition altering the nitrogen status of northeastern forests? BioScience 53: 375–389.CrossRefGoogle Scholar
  3. Alexander R.B., Johnes P.J., Boyer E.W. and Smith R.A. 2002. A comparison of models for estimating the riverine export of nitrogen from large watersheds. Biogeochemistry 57/58: 295–339.CrossRefGoogle Scholar
  4. Battaglin, W.A. and Goolsby, D.A. 1994. Spatial Data in Geographic Information System Format on Agricultural Chemical Use, Land Use, and Cropping Practices in the United States. USGS Water-Resources Investigations Report 94-4176 Report available online at Data available on-line at Scholar
  5. Boyer E.W., Goodale C.L., Jaworski N.A. and Howarth R.W. 2002. Effects of anthropogenic nitrogen loading on riverine nitrogen export in the northeastern US. Biogeochemistry 57&58: 137–169.CrossRefGoogle Scholar
  6. Bricker S.B., Clement C.G., Pirhalla D.E., Orland S.P. and Farrow D.G.G. 1999. National Estuarine Eutrophication Assessment: A Summary of Conditions, Historical Trends, and Future Outlook. National Ocean Service, National Oceanic and Atmospheric Administration, Silver Springs, MD.Google Scholar
  7. Caraco N.F. and Cole J.J. 1999. Human impact on nitrate export: An analysis using major world rivers. Ambio 28: 167–170.Google Scholar
  8. Cleveland C.C., Townsend A.R., Schimel D.S., Fisher H., Howarth R.W., Hedin L.O., Perakis S.S., Latty E.F., von Fischer J.C., Elseroad A. and Wasson M.F. 1999. Global patterns of terrestrial biological nitrogen (N2) fixation in natural systems. Global Biogeochem. Cycles 13: 623–645.CrossRefGoogle Scholar
  9. Cohn T.A. et al. 1992. The validity of a simple statistical model for estimating fluvial constituent loads: an empirical study involving loads entering the Chesapeake Bay. Water Resour. Res 28: 2353–2363.CrossRefGoogle Scholar
  10. Environmental Protection Agency 2001. National Coastal Condition Report. EPA-620/R-01/005, Office of Research and Development and Office of Water, U.S. Environmental Protection Agency, Washington, DC.Google Scholar
  11. Galloway J.N., Dentener F.J., Capone D.G., Boyer E.W., Howarth R.W., Seitzinger S.P., Asner G.P., Cleveland C., Green P.A., Holland E., Karl D.M., Michaels A., Porter J.H., Townsend A. and Vorosmarty C. 2004. Nitrogen cycles: past, present, and future. Biogeochemistry 70: 153–226.CrossRefGoogle Scholar
  12. Hagy J.D., Boynton W.R., Keefe C.W. and Wood K.V. 2004. Hypoxia in Chesapeake Bay, 1950–2001: Long-term change in relation to nutrient loading and river flow. Estuaries 27: 634–658.Google Scholar
  13. Holland E., Dentener F., Braswell B. and Sulzman J. 1999. Contemporary and pre-industrial global reactive nitrogen budgets. Biogeochemistry 4: 7–43.Google Scholar
  14. Howarth R.W. 1988. Nutrient limitation of net primary production in marine ecosystems. Annual Rev. Ecol. Systemat. 19: 89–110.CrossRefGoogle Scholar
  15. Howarth, R.W. In press. The development of policy approaches for reducing nitrogen pollution to coastal waters of the USA. China Science.Google Scholar
  16. Howarth R.W., Jensen H., Marino R. and Postma H. 1995. Transport to and processing of phosphorus in near-shore and oceanic waters. In: Tiessen H. (ed.), Phosphorus in the Global Environment, SCOPE #54, Wiley & Sons, Chichester, pp. 323–345.Google Scholar
  17. Howarth R.W., Billen G., Swaney D., Townsend A., Jaworski N., Lajtha K., Downing J.A., Elmgren R., Caraco N., Jordan T., Berendse F., Freney J., Kudeyarov V., Murdoch P. and Zhu Zhao-liang. 1996. Riverine inputs of nitrogen to the North Atlantic Ocean: fluxes and human influences. Biogeochemistry 35: 75–139.CrossRefGoogle Scholar
  18. Howarth R.W., Anderson D., Cloern J., Elfring C., Hopkinson C., Lapointe B., Malone T., Marcus N., McGlathery K., Sharpley A. and Walker D. 2000. Nutrient pollution of coastal rivers, bays, and seas. Issues Ecol. 7: 1–15.Google Scholar
  19. Howarth R.W., Boyer E.W., Pabich W.J. and Galloway J.N. 2002a. Nitrogen use in the United States from 1961-200 and potential future trends. Ambio 31: 88–96.PubMedGoogle Scholar
  20. Howarth R., Walker D. and Sharpley A. 2002b. Sources of nitrogen pollution to coastal waters of the United States. Estuaries 25: 656–676.Google Scholar
  21. Howarth R.W. and Marino R. 2006. Nitrogen as the limiting nutrient for eutrophication in coastal marine ecosystems: Evolving views over 3 decades. Limnol. Oceanogr. 51: 288–295.CrossRefGoogle Scholar
  22. Howarth R.W., Ramakrishna K., Choi E., Elmgren R., Martinelli L., Mendoza A., Moomaw W., Palm C., Boy R., Scholes M., and Zhu Zhao-Liang. 2006. Chapter 9: Nutrient Management, Responses Assessment. Ecosystems and Human Well Being. Vol. 3, Policy Responses. The Millenium Ecosystem Assessment. Island Press, Washington, DC, pp. 295–311.Google Scholar
  23. Kittel T.G.F., Royle J.A., Daly C., Rosenbloom N.A., Gibson W.P., Fisher H.H., Schimel D.S., Berliner L.M., and VEMAP2 Participants. 1997. A gridded historical (1895–1993) bioclimate dataset for the conterminous United States. In: Reno N.V. (ed.), Proceedings of the 10th Conference on Applied Climatology.Google Scholar
  24. Lewis W.M. 2002. Yield of nitrogen from minimally disturbed watersheds of the United States. Biogeochemistry 57/58: 375–385.CrossRefGoogle Scholar
  25. Lewis W.M., Melack J.M., McDowell W.H., McClain M., and Richey J.E. 1999. Nitrogen yields from undisturbed watersheds in the Americas. Biogeochemistry 46: 149–162.CrossRefGoogle Scholar
  26. Lovett G. and Lindberg S.E. 1993. Atmospheric deposition and canopy interactions of nitrogen in forests. Can. J. For. Res 23: 1603–1616.Google Scholar
  27. Lovett G.M. and Rueth H. 1999. Potential N mineralization and nitrification in American beech and sugar maple stands along a N deposition gradient in the northeastern US. Ecol. Appl. 9: 1330–1344.Google Scholar
  28. Lovett G.M., Traynor M.M., Pouyal R.V., Carreiro M.M., Zhu W.X. and Baxter J.W. 2000. Atmospheric deposition to oak forests along an urban-rural gradient. Env. Sci. Tech 34: 4294–4300.CrossRefGoogle Scholar
  29. McIsaac G.F., David M.B., Gertner G.Z. and Goolsby D.A. 2001. Net anthropogenic N input to the Mississippi River basin and nitrate flux to the Gulf of Mexico. Nature 414: 166–167.PubMedCrossRefGoogle Scholar
  30. Meyers T., Sickles J., Dennis R., Russell K., Galloway J. and Church T. 2001. Atmospheric nitrogen deposition to coastal estuaries and their watersheds. In: Valigura R.A., Alexander R.B., Castro M.S., Meyers T.P., Paerl H.W., Stacey P.E. and Turner R.E. (eds), Nitrogen Loading in Coastal Water Bodies: An Atmospheric Perspective, American Geophysical Union, Washington, DC, pp. 53–76.Google Scholar
  31. Moore M.H., Pace M., Mather J., Murdoch P.S., Howarth R.W., Folt C.L., Chen C.Y., Hemond H.F., Flebbe P.A. and Driscoll C.T. 1997. Potential effects of climate change on the freshwater ecosystems of the New England/mid-Atlantic region. Water Resources 11: 925–947.Google Scholar
  32. NADP. 2005. National Atmospheric Deposition Program/National Trends Network. NADP Program Office, Illinois State Water Survey, 2204 Griffith Dr., Champaign, IL 61820. [online] URL: Scholar
  33. Najjar R.G. 1999. The water balance of the Susquehanna River basin and its response to climate change. J. Hydrol. 219: 7–19.CrossRefGoogle Scholar
  34. Najjar R.G., Walker H.A., Anderson P.J., Barron E.J., Bord R.J., Gibson J.R., Kennedy V.S., Knight C.G., Megonigal J.P., O’Connor R.E., Polsky C.D., Psuty N.P., Richards B.A., Soreson L.G., Steele E.M. and Swanson R.S. 2000. The potential impacts of climate change on the mid-Atlantic coastal region. Climate Res. 14: 219–233.Google Scholar
  35. NRC 2000. Clean Coastal Waters: Understanding and Reducing the Effects of Nutrient Pollution. National Academies Press, Washington, DC.Google Scholar
  36. Nixon S.W. 1995. Coastal marine eutrophication: a definition, social causes, and future concerns. Ophelia 41: 199–219.Google Scholar
  37. Ollinger S.V., Aber J.D., Lovett G.M., Millham S.E., Lathrop R.G. and Ellis J.M. 1993. A spatial model of atmospheric deposition for the northeastern U.S.. Ecol. Appl. 3: 459–472.Google Scholar
  38. Prospero J.M., Barrett K., Church T., Dentener F., Duce R.A., Galloway J.N., Levy H., Moody J. and Quinn P. 1996. Atmospheric deposition of nutrients to the North Atlantic Basin. Biogeochemistry 35: 27–73.CrossRefGoogle Scholar
  39. Peierls B., Caraco N., Pace M. and Cole J.J. 1991. Human influence on river nitrogen. Nature 350: 386–387.CrossRefGoogle Scholar
  40. Randall G.W. and Mulla D.J. 2001. Nitrate nitrogen in surface waters as influence by climatic conditions and agricultural practices. J. Environ. Qual. 30: 337–344.PubMedGoogle Scholar
  41. Randall G.W., Huggins D.R., Russelle M.P., Fuchs D.J., Nelson W.W. and Anderson J.L. 1997. Nitrate losses through subsurface tile drainage in CRP, alfalfa, and row crop systems. J. Environ. Qual 26: 1240–1247.CrossRefGoogle Scholar
  42. Scavia D., Field J.C., Boesch, Buddemeier R., Burkett V., Canyan D., Fogarty M., Harwell M.A., Howarth R.W., Mason C., Reed D.J., Royer T.C., Sallenger A.H. and Titus J.G. 2002. Climate change impacts on US coastal and marine ecosystems. Estuaries 25: 149–164.CrossRefGoogle Scholar
  43. Seitzinger S.P. and Kroeze C. 1998. Global distribution of nitrous oxide production and N inputs in freshwater and coastal marine ecosystems. Global Biogeochem. Cycles 12: 93–113.CrossRefGoogle Scholar
  44. Seitzinger S.P., Styles R.V., Boyer E.W., Alexander R., Billen G., Howarth R., Mayer B. and van Breemen N. 2002. Nitrogen retention in rivers: model development and application to watersheds in the northeastern US. Biogeochemistry 57&58: 199–237.CrossRefGoogle Scholar
  45. Smith S.V., Swaney D., Talaue-McManus L., Bartley J.D., Sandhei P.T., McLaughlin C.J., Dupra V.C., Crossland C.J., Buddemeier R.W., Maxwell B.A. and Wulff F. 2003. Humans, hydrology, and thedistribution of inorganic nutrient loading to the ocean. BioScience 53: 235–245.CrossRefGoogle Scholar
  46. Staver K.W. and Brinsfield R.B. 1998. Use of cereal grain winter cover crops to reduce groundwater nitrate contamination in the Mid-Atlantic coastal plain. J. Soil Water Conserv. 53: 230–240.Google Scholar
  47. USGS. 2005. National Water Information System Data Retrieval [online] URL: Scholar
  48. Van Breemen N., Boyer E.W., Goodale C.L., Jaworski N.A., Paustian K., Seitzinger S., Lajtha K., Mayer B., van Dam D., Howarth R.W., Nadelhoffer K.J., Eve M. and Billen G. 2002. Where did all the nitrogen go? Fate of nitrogen inputs to large watersheds in the northeastern USA. Biogeochemistry 57&58: 267–293.CrossRefGoogle Scholar
  49. Van Horn H.H. 1998. Factors affecting manure quantity, quality, and use. Proceedings of the Mid-South Ruminant Nutrition Conference, Dallas-Ft. Worth, May 7–8, 1998. Texas Animal Nutrition Council, pp 9–20.Google Scholar
  50. Wolock D.M. and McCabe G.M. 1999. Simulated effects of climate change on mean annual runoff in the conterminous Unites States. J. Am. Wat. Res. Assoc. 35: 1341–1350.Google Scholar

Copyright information

© Springer 2006

Authors and Affiliations

  • R. W. Howarth
    • 1
  • D. P. Swaney
    • 1
  • E. W. Boyer
    • 2
  • R. Marino
    • 1
  • N. Jaworski
    • 3
  • C. Goodale
    • 1
  1. 1.Department of Ecology & Evolutionary BiologyCornell UniversityIthacaUSA
  2. 2.Department of Environmental Science, Policy & ManagementUniversity of CaliforniaBerkeleyUSA
  3. 3.U.S. Environmental Protection Agency (retired)NarragansettUSA

Personalised recommendations