Recent Changes in Nitrogen Sources and Load Components to Estuaries of the Contiguous United States
Regional Spatially Referenced Regressions on Watershed models were used to update 2002 delivered nitrogen (N) loads to estuaries of the contiguous US for 2011, supplemented by direct estuarine atmospheric deposition from the Community Multiscale Air Quality Model. Median 2011 watershed N yields were greatest for the Puget Trough, Virginian, and Oregon–Washington–Vancouver Coast marine ecoregions (MEs; 13.7, 11.0, and 9.9 kg N/ha watershed/year, respectively); intermediate for the Floridian, Southern California Bight, and Northern California MEs (4.4–6.3 kg N/ha watershed/year); and lowest for the Northern Gulf of Mexico, Carolinian, and Gulf of Maine MEs (2.4–3.2 kg N/ha watershed/year). Dominant sources varied across marine ecoregions, with direct atmospheric deposition as the dominant source only in the far northern Gulf of Maine ME. Delivered N loads from atmospheric deposition have significantly decreased (p < 0.05) for most estuaries on the Atlantic and Gulf coasts for 2002–2012. Estimated point source delivered N loads for 2002–2012 increased for most estuaries with upstream treatment plants, with estimated loads to only seven estuaries decreasing by more than 50%. Urban runoff increased for most estuaries in the Puget Trough and Carolinian MEs and either increased or had no significant trend for the remaining marine ecoregions. The magnitude of change in total N delivered loads is uncertain due to incomplete monitoring for most minor dischargers. In areas with increased population growth and decreases in agricultural land, decreasing agricultural fertilizer inputs have been insufficient to offset increases in urban runoff.
KeywordsNitrogen loading Estuaries United States SPARROW models
This is contribution number ORD-027336 of the Atlantic Ecology Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency (US EPA). The views expressed in this article are those of the authors and do not necessarily reflect the views or policies of the US EPA. Mention of trade names or commercial products does not constitute endorsement or recommendation for use. The authors thank Drs. Brenda Rashleigh, Daniel Campbell, and Galen Kaufman for providing preliminary technical reviews of this manuscript as well as the two anonymous reviewers of the final publication.
Support for this work (funding for ORISE participants through an interagency agreement with the Department of Energy - Oak Ridge Associated Universities) was provided by the USEPA through the Integrated Nitrogen Project under US EPA Safe and Healthy Communities research program. The information in this document has been funded wholly by the US EPA.
Compliance with Ethical Standards
Conflict of Interest
The authors declare that they have no conflict of interest.
- Alam, M.J., J.L. Goodall, B.D. Bowes, and E.G. Girvetz. 2017. The impact of projected climate change scenarios on nitrogen yield at a regional scale for the contiguous United States. JAWRA 53 (4): 854–870.Google Scholar
- Beachley, G., M. Puchalski, C. Rogers, and G. Lear. 2016. A summary of long-term trends in sulfur and nitrogen deposition in the United States: 1990-2013. JSM Environ Sci Ecol 4 (2): 1030.Google Scholar
- Brakebill, J.W., and S.E. Terziotti. 2011. A digital hydrologic network supporting NAWQA MRB SPARROW modeling—MRB_E2RF1. Version 1.0. Reston, VA: U.S. Geological Survey https://water.usgs.gov/lookup/getspatial?mrb_e2rf1.Google Scholar
- Breitburg, D.L., D.W. Hondorp, L.A. Davias, and R.J. Diaz. 2009. Hypoxia, nitrogen, and fisheries: Interpreting effects across local and global landscapes. Annual Review of Marine Science 1: 329–349. https://doi.org/10.1146/annurev.marine.010908.163754.CrossRefGoogle Scholar
- Bricker, S.B., B. Longstaff, W. Dennison, A. Jones, K. Boicourt, C. Wicks, et al. 2007. Effects of nutrient enrichment in the nation’s estuaries: A decade of change. NOAA Coastal Ocean Program, Decision Analysis Series 26. Silver Spring, MD: National Centers for Coastal Ocean Science.Google Scholar
- Cleveland, C.C., A.R. Townsend, D.S. Schimel, H. Fisher, R.W. Howarth, L.O. Hedin, S.S. Perakis, E.F. Latty, J.C. Von Fischer, A. Elseroad, and M.F. Wasson. 1999. Global patterns of terrestrial biological nitrogen (N2) fixation in natural ecosystems. Global Biogeochem Cycles 13: 623–645.CrossRefGoogle Scholar
- De Cicco, L.A., Sprague, L.A., Murphy, J.C., Riskin, M.L., Falcone, J.A., Stets, E.G., Oelsner, G.P., and Johnson, H.M., 2017, Water-quality and streamflow datasets used in the Weighted Regressions on Time, Discharge, and Season (WRTDS) models to determine trends in the Nation’s rivers and streams, 1972-2012 (ver. 1.1 July 7, 2017): U.S. Geological Survey data release, doi: https://doi.org/10.5066/F7KW5D4H.
- Detenbeck, N, M. Pelletier, N. ten Brink, M. Abdelrhman, and S. Rego. 2009 E-estuary: Developing a decision-support system for coastal management in the conterminous United States. Proceedings, 33rd IAHR 2009 Congress - Water Engineering for a Sustainable Environment. Vancouver, BC. 5284–5292.Google Scholar
- Diaz, R.J., and R. Rosenberg. 2008. Spreading dead zones and consequences for marine ecosystems. Science 2008 321 (5891): 926–929.Google Scholar
- FGDC. 2012. Coastal and marine ecological classification standard. Marine and Coastal Spatial Data Subcommittee Federal Geographic Data Committee Washington, DC. FGDC-STD-018-2012.Google Scholar
- Hickman, R.E., 2017, Input data and results of WRTDS models and seasonal rank-sum tests to determine trends in the quality of water in New Jersey streams, water years 1971–2011: U.S. Geological Survey data release, doi: https://doi.org/10.5066/F7NS0RZ3.
- Hoos, A.B., R.B. Moore, A.M. Garcia, G.B. Noe, S.E. Terziotti, C.M. Johnston, and R.L. Dennis. 2013. Simulating stream transport of nutrients in the eastern United States, 2002, using a spatially-referenced regression model and 1:100,000-scale hydrography. U.S. Geological Survey Scientific Investigations Report 2013–5102, 33 p., http://pubs.usgs.gov/sir/2013/5102/.
- Howarth, R.W., G. Billen, D. Swaney, A. Townsend, N. Jaworski, K. Lajtha, et al. 1996. Regional nitrogen budgets and riverine N and P fluxes for the drainages to the North Atlantic Ocean: Natural and human influences. Biogeochemistry 35: 75–139. https://doi.org/10.1007/BF02179825.CrossRefGoogle Scholar
- HTF (Hypoxia Task Force). 2016. Report on point source progress in hypoxia task force states. Febr. 2016. Available at: https://www.epa.gov/sites/production/files/2016-03/documents/htf_pointsource_progressreport_02-25-16_508.pdf
- Liu, X., Y. Zhang, W.Han.A. Tang, J. Shen, Z. Cui, P. Vitousek, J.W. Erisnam, K. Goulding, P. Christie, A. Fangmeier, and F. Zhang. 2013. Enhanced nitrogen deposition over China. Nature 494: 459–463.Google Scholar
- Mayorga, E., S. Seitzinger, A.F. Harrison, E. Dumont, A.H.W. Beusen, A.F. Bouwman, et al. 2010. Global nutrient export from WaterSheds 2 (NEWS 2): Model development and implementation. Environmental Modelling and Software. https://doi.org/10.1016/j.envsoft.2010.1001.1007.
- Moorman, M.C., A.B. Hoos, S.B. Bricker, R.B. Moore, A.M. García, and S.W. Ator. 2014. Nutrient load summaries for major lakes and estuaries of the Eastern United States, 2002: U.S. Geological Survey Data Series 820, 94 p., doi: https://doi.org/10.3133/ds82 https://water.usgs.gov/nawqa/sparrow/estuary/index.html0.
- Narragansett Bay Estuary Program. 2017. State of Narragansett Bay and its watershed (Chapter 8, nutrient loading, pages 166–189). Technical report. Providence, RI.Google Scholar
- Oelsner, G.P., Sprague, L.A., Murphy, J.C., Zuellig, R.E., Johnson, H.M., Ryberg, K.R., Falcone, J.A., Stets, E.G., Vecchia, A.V., Riskin, M.L., De Cicco, L.A., Mills, T.J., Farmer, W.H., 2017, Water-quality trends in the nation’s rivers and streams 1972–2012—Data preparation, statistical methods, and trend results: U.S. Geological Survey Scientific Investigations Report, doi: https://doi.org/10.3133/sir20175006.
- Pohlert, T. 2018. Non-parametric trend tests and change-point detection. citation(package="trend").Google Scholar
- PREP (Piscatagua Region Estuaries Partnership). 2018. Environmental data report: Technical support document for the 2018 State of Our Estuaries Report. Available at www.PREPestuaries.org.
- Preston, S.D., R.B. Alexander, and D.M. Wolock. 2011. SPARROW modeling to understand water-quality conditions in major regions of the United States: A featured collection introduction. Journal of the American Water Resources Association (JAWRA) 47 (5): 887–890. https://doi.org/10.1111/j.1752-1688.2011.00585.x.CrossRefGoogle Scholar
- Pritchard, D.W. 1967. What is an estuary: Physical viewpoint. In Lauf, G. H. Estuaries. A.A.A.S. Publ. 83. Washington, DC. pp. 3–5.Google Scholar
- Rebich, R.A., N.A. Houston, S.V. Mize, D.K. Pearson, P.B. Ging, and C.E. Hornig. 2011. Sources and delivery of nutrients to the northwestern Gulf of Mexico from streams in the south-central United States. Journal of the American Water Resources Association (JAWRA) 47 (5): 1061–1086. https://doi.org/10.1111/j.1752-1688.2011.00583.x.CrossRefGoogle Scholar
- SAB (U.S. Environmental Protection Agency Science Advisory Board). 2007. Hypoxia in the northern Gulf of Mexico: An update by the EPA Science Advisory Board. EPA-SAB-08-003. Washington, D.C.: U.S. Environmental Protection Agency Science Advisory Board.Google Scholar
- Saleh, D., and J. Domagalski. 2015. SPARROW modeling of nitrogen sources and transport in rivers and streams of California and adjacent states, U.S. JAWRA 51 (6): 1487–1507.Google Scholar
- Schwarz, G.E., A.B. Hoos, R.B. Alexander, and R.A. Smith. 2006. The SPARROW surface water-quality model: Theory, application, and user documentation, U.S. Geological Survey Techniques and Methods Report, Book 6, Chapter B3.Google Scholar
- Smith, R., J. Brakebill, G. Schwarz, R. Alexander, M. Hirsch, A. Nolin, M. Macauley, Q. Zhang, J Shih, W. Wang, and E. Sproles. 2011. Dynamic SPARROW modeling of nitrogen flux with climate and MODIS vegetation indices as drivers. AGU Fall Meeting Abstracts. 1378.Google Scholar
- Spalding, M.D., H.E. Fox, G.R. Allen, N. Davidson, Z.A. Ferdaña, M. Finlayson, B.S. Halpern, M.A. Jorge, A. Lombana, S.A. Lourie, K.D. Martin, E. McManus, J. Molnar, C.A. Recchia, and J. Robertson. 2007. Marine ecoregions of the world: A bioregionalization of coastal and shelf areas. BioScience 57 (7): 573–583.CrossRefGoogle Scholar
- US EPA. 2004. Coastal classification framework. National Health and Environmental Effects Research Laboratory. Atlantic, Gulf, and Mid-Continent Ecology Divisions. EPA Report 600/R-04/061.Google Scholar
- US EPA. 2010a. Nutrient criteria technical guidance manual estuarine and coastal marine waters. United States Environmental Protection Agency Office of Water. EPA-822-B-01-003. October 2001.Google Scholar
- US EPA. 2010b. Nutrients in estuaries: A summary report of the National Estuarine Experts Workgroup 2005–2007. Washington, D.C.: U.S. Environmental Protection Agency.Google Scholar
- US EPA. 2011. Reactive nitrogen in the United States: An analysis of inputs, flows, consequences, and management options, EPA-SAB-11-013; EPA Science Advisory Board; p 140.Google Scholar
- US EPA. 2012. Technical users background document for the discharge monitoring report (DMR) pollutant loading tool version 1.0 Washington, D.C.: U.S. Environmental Protection Agency. Available at: https://echo.epa.gov/system/files/Technical_Users_Background_Doc.pdf
- US EPA. 2014. Clean air markets progress report NOx emissions reductions. (Available at: https://www3.epa.gov/airmarkets/progress/reports/emissions_reductions_nox.html#figure1).
- US EPA. 2015. Office of Water and Office of Research and Development. (2015). National coastal condition assessment 2010 (EPA 841-R-15-006). Washington, DC. December 2015.Google Scholar
- US EPA. 2016. Clean watershed needs survey 2012: Report to Congress. U.S. Environmental Protection Agency, Washington, DC. EPA-830-R-15005.Google Scholar
- US EPA. 2017a. Mississippi River/Gulf of Mexico Watershed Nutrient Task Force 2017 report to congress: Second biennial report. August 2017. Google Scholar
- US EPA. 2017b. Action towards limiting total nitrogen, total phosphorus, and total inorganic nitrogen loads from NPDES-permitted facilities. Accessed 7/13/18 from https://19january2017snapshot.epa.gov/nutrient-policy-data/action-towards-limiting-total-nitrogen-total-phosphorus-and-total-inorganic_.html.
- Van Meter, K.J., P. Van Cappellen, and N.B. Basu. 2018. Legacy nitrogen may prevent achievement of water quality goals in the Gulf of Mexico. Science 22 Mar 2018: eaar4462. https://doi.org/10.1126/science.aar4462.
- Wasson, K., R. Jeppesen, C. Endris, D.C. Perry, A. Woolfook, K. Beheshti, M. Rodriguez, R. Eby, E.B. Watshon, F. Rahman, J. Haskins, and B.B. Hughes. 2017. Eutrophication decreases salt marsh resilience through proliferation of algal mats. Biological Conservation 212: 1–11.Google Scholar
- Wise, D.R., and Johnson, H.M., 2013, Application of the SPARROW model to assess surface-water nutrient conditions and sources in the United States Pacific Northwest: U.S. Geological Survey Scientific Investigations Report 2013–5103, 32 p., http://pubs.usgs.gov/sir/2013/5103/.
- Yagecic, J.R., D. Sayers, P.J. V’Combe, S. McAleer, and C. Pindar. 2016. Impact of treatment plant type on point discharge effluent nutrient concentrations in the Delaware River basin. West Trenton, NJ: Delaware River Basin Commission.Google Scholar
- Zhang, Y.R. Mathur, J.O. Bash, C. Hogrefe, J. Xing, and S.J. Roselle. 2018. Long-term trends in total inorganic nitrogen and sulfur deposition in the U.S. from 1990 to 2010. Atmospheric Chemistry and Physics Discussions. https://doi.org/10.5194/acp-2018-116.