Increasing incidences of eutrophication and groundwater quality impairment from agricultural nitrogen pollution are threatening humans and ecosystem health. Minimal improvements in water quality have been achieved despite billions of dollars invested in conservation measures worldwide. Such apparent failures can be attributed in part to legacy nitrogen that has accumulated over decades of agricultural intensification and that can lead to time lags in water quality improvement. Here, we identify the key knowledge gaps related to landscape nitrogen legacies and propose approaches to manage and improve water quality, given the presence of these legacies.
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Diaz, R. J. & Rosenberg, R. Introduction to environmental and economic consequences of hypoxia. Int. J. Water Resour. Dev. 27, 71–82 (2011).
Glibert, P. M., Maranger, R., Sobota, D. J. & Bouwman, L. The Haber Bosch–harmful algal bloom (HB–HAB) link. Environ. Res. Lett. 9, 105001 (2014).
Sutton, M. A. et al. (eds) The European Nitrogen Assessment (Cambridge Univ. Press, 2011); http://www.nine-esf.org/node/360/ENA-Book.html
Basu, N. B. et al. Nutrient loads exported from managed catchments reveal emergent biogeochemical stationarity. Geophys. Res. Lett. 37, L23404 (2010).
Gobler, C. J. Climate change and harmful algal blooms: insights and perspective. Harmful Algae 91, 101731 (2020).
Wurtsbaugh, W. A., Paerl, H. W. & Dodds, W. K. Nutrients, eutrophication and harmful algal blooms along the freshwater to marine continuum. WIREs Water 6, 706 (2019).
D’Elia, C. F., Bidjerano, M. & Wheeler, T. B. in Coasts and Estuaries (eds Wolanski, E., Day, J. W., Elliott, M. and Ramachandran, R.) 293–310 (Elsevier, 2019).
Iho, A., Ribaudo, M. & Hyytiäinen, K. Water protection in the Baltic Sea and the Chesapeake Bay: institutions, policies and efficiency. Mar. Pollut. Bull. 93, 81–93 (2015).
Rabotyagov, S. S., Kling, C. L. & Gassman, P. W. The economics of dead zones: causes, impacts, policy challenges, and a mode of the Gulf of Mexico hypoxic zone. Rev. Environ. Econ. Policy https://doi.org/10.1093/reep/ret024 (2014).
Le Moal, M. et al. Eutrophication: a new wine in an old bottle? Sci. Total Environ. 651, 1–11 (2019).
Karydis, M. & Kitsiou, D. Eutrophication and environmental policy in the Mediterranean Sea: a review. Environ. Monit. Assess. 184, 4931–4984 (2012).
Linke, S., Gilek, M., Karlsson, M. & Udovyk, O. Unravelling science–policy interactions in environmental risk governance of the Baltic Sea: comparing fisheries and eutrophication. J. Risk Res. 17, 505–523 (2014).
Van Meter, K. J., Van Cappellen, P. & Basu, N. B. Response to comment on ‘Legacy nitrogen may prevent achievement of water quality goals in the Gulf of Mexico’. Science 365, eaau8401 (2019).
Van Meter, K. J., Van Cappellen, P. & Basu, N. B. Legacy nitrogen may prevent achievement of water quality goals in the Gulf of Mexico. Science 360, 427–430 (2018).
Destouni, G., Fischer, I. & Prieto, C. Water quality and ecosystem management: data-driven reality check of effects in streams and lakes. Water Resour. Res. 53, 6395–6406 (2017).
Meals, D. W., Dressing, S. A. & Davenport, T. E. Lag time in water quality response to best management practices: a review. J. Environ. Qual. 39, 85–96 (2010).
Backer, H. et al. HELCOM Baltic Sea Action Plan–a regional programme of measures for the marine environment based on the ecosystem approach. Mar. Pollut. Bull. 60, 642–649 (2010).
Gren, I.-M. & Destouni, G. Does divergence of nutrient load measurements matter for successful mitigation of marine eutrophication? AMBIO 41, 151–160 (2012).
Baltic Sea Action Plan (HELCOM, 2007).
The Nitrates Directive 1991/676/EEC (European Commission,1991).
Directive 2000/60/EC of the European Parliament and of the Council Establishing a Framework for the Community Action in the Field of Water Policy (European Environment Agency, 2020).
Diaz, R., Selman M. & Chique C. Global Eutrophic and Hypoxic Coastal Systems (World Resources Institute, 2011); https://datasets.wri.org/dataset/eutrophication-hypoxia-map-data-set
Boesch, D. F. Barriers and bridges in abating coastal eutrophication. Front. Mar. Sci. 6, 123 (2019).
Secchi, S. & Mcdonald, M. The state of water quality strategies in the Mississippi River basin: is cooperative federalism working? Sci. Total Environ. 677, 241–249 (2019).
Prokopy, L. S. et al. The urgency of transforming the Midwestern US landscape into more than corn and soybean. Agric. Human Values 37, 537–539 (2020).
Van Meter, K. J., Basu, N. B. & Van Cappellen, P. Two centuries of nitrogen dynamics: legacy sources and sinks in the Mississippi and Susquehanna river basins. Glob. Biogeochem. Cycles 31, 2016GB005498 (2017).
Van Meter, K. J. & Basu, N. B. Catchment legacies and time lags: a parsimonious watershed model to predict the effects of legacy storage on nitrogen export. PLoS ONE 10, e0125971 (2015).
Ardón, M., Helton, A. M., Scheuerell, M. D. & Bernhardt, E. S. Fertilizer legacies meet saltwater incursion: challenges and constraints for coastal plain wetland restoration. Elementa https://doi.org/10.1525/elementa.236 (2017).
Puckett, L. J., Tesoriero, A. J. & Dubrovsky, N. M. Nitrogen contamination of surficial aquifers—a growing legacy. Environ. Sci. Technol. 45, 839–844 (2011).
Poffenbarger, H. J. et al. Legacy effects of long-term nitrogen fertilizer application on the fate of nitrogen fertilizer inputs in continuous maize. Agric. Ecosyst. Environ. 265, 544–555 (2018).
Ascott, M. J. et al. Global patterns of nitrate storage in the vadose zone. Nat. Commun. 8, 1416 (2017).
Vero, S. E. et al. The environmental status and implications of the nitrate time lag in Europe and North America. Hydrogeol. J. 26, 7–22 (2017).
Tesoriero, A. J., Duff, J. H., Saad, D. A., Spahr, N. E. & Wolock, D. M. Vulnerability of streams to legacy nitrate sources. Environ. Sci. Technol. 47, 3623–3629 (2013).
Rudolph, D. L. Groundwater quality within the agricultural landscape: assessing the performance of nutrient BMPs. Ground Water Monit. Remediat. 35, 21–22 (2015).
Van Meter, K. J., Basu, N. B., Veenstra, J. J. & Burras, C. L. The nitrogen legacy: emerging evidence of nitrogen accumulation in anthropogenic landscapes. Environ. Res. Lett. 11, 035014 (2016).
Akbarzadeh, Z., Maavara, T., Slowinski, S. & Van Cappellen, P. Effects of damming on river nitrogen fluxes: a global analysis. Glob. Biogeochem. Cycles 33, 1339–1357 (2019).
Darracq, A., Lindgren, G. & Destouni, G. Long-term development of phosphorus and nitrogen loads through the subsurface and surface water systems of drainage basins. Global Biogeochem. Cycles 22 (2008).
van Egmond, K., Bresser, T. & Bouwman, L. The European nitrogen case. Ambio 31, 72–78 (2002).
van Van Breemen, N. et al. Where did all the nitrogen go? Fate of nitrogen inputs to large watersheds in the northeastern USA. Biogeochemistry 57, 267–293 (2002).
Howarth, R. W., Boyer, E. W., Pabich, W. J. & Galloway, J. N. Nitrogen use in the United States from 1961–2000 and potential future trends. Ambio 31, 88–96 (2002).
Howden, N. J. K., Burt, T. P., Worrall, F., Whelan, M. J. & Bieroza, M. Nitrate concentrations and fluxes in the River Thames over 140 years (1868–2008): are increases irreversible? Hydrol. Process. 24, 2657–2662 (2010).
Boland-Brien, S. J., Basu, N. B. & Schilling, K. E. Homogenization of spatial patterns of hydrologic response in artificially drained agricultural catchments. Hydrol. Process. 28, 5010–5020 (2014).
Sloan, B. P., Basu, N. B. & Mantilla, R. Hydrologic impacts of subsurface drainage at the field scale: climate, landscape and anthropogenic controls. Agric. Water Manage. 165, 1–10 (2016).
Schilling, K. E., Jindal, P., Basu, N. B. & Helmers, M. J. Impact of artificial subsurface drainage on groundwater travel times and baseflow discharge in an agricultural watershed, Iowa (USA). Hydrol. Process. 26, 3092–3100 (2012).
Hong, B. et al. Evaluating regional variation of net anthropogenic nitrogen and phosphorus inputs (NANI/NAPI), major drivers, nutrient retention pattern and management implications in the multinational areas of Baltic Sea basin. Ecol. Modell. 227, 117–135 (2012).
Boyer, E. W., Goodale, C. L., Jaworski, N. A. & Howarth, R. W. Anthropogenic nitrogen sources and relationships to riverine nitrogen export in the northeastern USA. Biogeochemistry 57, 137–169 (2002).
Howarth, R. W. et al. Nitrogen fluxes from the landscape are controlled by net anthropogenic nitrogen inputs and by climate. Front. Ecol. Environ. 10, 37–43 (2012).
Van Meter, K. J. & Basu, N. B. Time lags in watershed-scale nutrient transport: an exploration of dominant controls. Environ. Res. Lett. 12, 084017 (2017).
Chen, D. et al. Legacy nutrient dynamics at the watershed scale: principles, modeling, and implications. Adv. Agron. 149, 237–313 (2018).
Wellen, C., Kamran-Disfani, A.-R. & Arhonditsis, G. B. Evaluation of the current state of distributed watershed nutrient water quality modeling. Environ. Sci. Technol. 49, 3278–3290 (2015).
Wit, M. J. Mde Nutrient fluxes at the river basin scale. I: the PolFlow model. Hydrol. Process. 15, 743–759 (2001).
Rabotyagov, S. S. et al. Cost-effective targeting of conservation investments to reduce the northern Gulf of Mexico hypoxic zone. Proc. Natl Acad. Sci. USA 111, 18530–18535 (2014).
McIsaac, G. F., David, M. B., Gertner, G. Z. & Goolsby, D. A. Relating net nitrogen input in the Mississippi River basin to nitrate flux in the lower Mississippi River: a comparison of approaches. J. Environ. Qual. 31, 1610–1622 (2002).
Chen, F. et al. Net anthropogenic nitrogen inputs (NANI) into the Yangtze River basin and the relationship with riverine nitrogen export. J. Geophys. Res. Biogeosci. 121, 451–465 (2016).
Chang, S. Y., Zhang, Q., Byrnes, D. K., Basu, N. B. & Van Meter, K. J. Chesapeake legacies: the importance of legacy nitrogen to improving Chesapeake Bay water quality. Environ. Res. Lett. 16, 085002 (2021).
Van Meter, K. J. et al. Beyond the mass balance: watershed phosphorus legacies and the evolution of the current water quality policy challenge. Water Resour. Res. 57 (2021).
Wang, L. et al. Prediction of the arrival of peak nitrate concentrations at the water table at the regional scale in Great Britain. Hydrol. Process. 26, 226–239 (2012).
Lee, M., Shevliakova, E., Malyshev, S., Milly, P. C. D. & Jaffé, P. R. Climate variability and extremes, interacting with nitrogen storage, amplify eutrophication risk. Geophys. Res. Lett. 43, 7520–7528 (2016).
Ilampooranan, I., Van Meter, K. J. & Basu, N. B. A race against time: modeling time lags in watershed response. Water Resour. Res. 55, 3941–3959 (2019).
Guillaumot, L. et al. A hillslope-scale aquifer-model to determine past agricultural legacy and future nitrate concentrations in rivers. Sci. Total Environ 800, 149216 (2021).
Keiser, D. A., Kling, C. L. & Shapiro, J. S. The low but uncertain measured benefits of US water quality policy. Proc. Natl Acad. Sci. USA 116, 5262–5269 (2019).
Keiser, D. A. & Shapiro, J. S. Consequences of the Clean Water Act and the demand for water quality. Q. J. Econ. 134, 349–396 (2019).
Sprague, L. A. & Gronberg, J. A. M. Relating management practices and nutrient export in agricultural watersheds of the United States. J. Environ. Qual. 41, 1939–1950 (2012).
Zabel, T., Milne, I. & Mckay, G. Approaches adopted by the European Union and selected Member States for the control of urban pollution. Urban Water 3, 25–32 (2001).
Booth, L. & Quinn, F. Twenty-five years of the Canada Water Act. Can. Water Resour. J. 20, 65–90 (1995).
Liu, Y. Phosphorus Flows in China: Physical Profiles and Environmental Regulation. PhD thesis, Wageningen Univ. (2005).
Jacobsen, B. H., Anker, H. T. & Baaner, L. Implementing the water framework directive in Denmark—lessons on agricultural measures from a legal and regulatory perspective. Land Use Policy 67, 98–106 (2017).
Ascott, M. J. et al. The need to integrate legacy nitrogen storage dynamics and time lags into policy and practice. Sci. Total Environ 781, 146698 (2021).
Yan, M., Pan, G., Lavallee, J. M. & Conant, R. T. Rethinking sources of nitrogen to cereal crops. Glob. Change Biol. 26, 191–199 (2020).
Rudolph, D. L., Devlin, J. F. & Bekeris, L. Challenges and a strategy for agricultural BMP monitoring and remediation of nitrate contamination in unconsolidated aquifers. Ground Water Monit. Remediat. 35, 97–109 (2015).
Dalgaard, T. et al. Policies for agricultural nitrogen management—trends, challenges and prospects for improved efficiency in Denmark. Environ. Res. Lett. 9, 115002 (2014).
Eagle, A. J., Olander, L. P., Locklier, K. L., Heffernan, J. B. & Bernhardt, E. S. Fertilizer management and environmental factors drive N2O and NO3 losses in corn: a meta-analysis. Soil Sci. Soc. Am. J. 81, 1191–1202 (2017).
Khanna, M., Gramig, B. M., DeLucia, E. H., Cai, X. & Kumar, P. Harnessing emerging technologies to reduce Gulf hypoxia. Nat. Sustain. 2, 889–891 (2019).
Cheng, F. Y., Van Meter, K. J., Byrnes, D. K. & Basu, N. B. Maximizing US nitrate removal through wetland protection and restoration. Nature https://doi.org/10.1038/s41586-020-03042-5 (2020).
Qiu, J., Wardropper, C. B., Rissman, A. R. & Turner, M. G. Spatial fit between water quality policies and hydrologic ecosystem services in an urbanizing agricultural landscape. Landsc. Ecol. 32, 59–75 (2017).
Jacobsen, B. H. & Hansen, A. L. Economic gains from targeted measures related to non-point pollution in agriculture based on detailed nitrate reduction maps. Sci. Total Environ. 556, 264–275 (2016).
Destouni, G. & Jarsjö, J. Zones of untreatable water pollution call for better appreciation of mitigation limits and opportunities. WIREs Water 5, e1312 (2018).
Hansen, A. T. et al. Integrated assessment modeling reveals near-channel management as cost-effective to improve water quality in agricultural watersheds. Proc. Natl Acad. Sci. USA 118, e2024912118 (2021).
Cheng, F. Y. & Basu, N. B. Biogeochemical hotspots: role of small water bodies in landscape nutrient processing. Water Resour. Res. 53, 5038–5056 (2017).
Early June 2019 Hypoxia Report (Maryland Department of Natural Resources, 2019); https://news.maryland.gov/dnr/2019/06/27/early-june-2019-hypoxia-report/
Mississippi River/Gulf of Mexico Watershed Nutrient Task Force 2015 Report to Congress (EPA, 2015).
Hypoxia Task Force 2001 Action Plan (EPA, 2001).
Reckhow, K. H. et al. Achieving Nutrient and Sediment Reduction Goals in the Chesapeake Bay: An Evaluation of Program Strategies and Implementation (National Academies Press, 2011).
Savchuk, O. P. Large-scale nutrient dynamics in the Baltic Sea, 1970–2016. Front. Mar. Sci. 5, 95 (2018).
Carstensen, J., Andersen, J. H., Gustafsson, B. G. & Conley, D. J. Deoxygenation of the Baltic Sea during the last century. Proc. Natl Acad. Sci. USA 111, 5628–5633 (2014).
Northern Gulf of Mexico Hypoxic Zone (EPA, 2020).
Swaney, D. P., Hong, B., Ti, C., Howarth, R. W. & Humborg, C. Net anthropogenic nitrogen inputs to watersheds and riverine N export to coastal waters: a brief overview. Curr. Opin. Environ. Sustain. 4, 203–211 (2012).
Oelsner, G. P. et al. Water-Quality Trends in the Nation’s Rivers and Streams, 1972–2012—Data Preparation, Statistical Methods, and Trend Results (USGS, 2017); https://doi.org/10.3133/sir20175006
Goyette, J.-O., Bennett, E. M., Howarth, R. W. & Maranger, R. Changes in anthropogenic nitrogen and phosphorus inputs to the St. Lawrence sub-basin over 110 years and impacts on riverine export. Glob. Biogeochem. Cycles 30, 1000–1014 (2016).
De Cicco, L.A. et al. 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) (USGS, 2017); https://doi.org/10.5066/F7KW5D4H
Bouraoui, F. & Grizzetti, B. Long term change of nutrient concentrations of rivers discharging in European seas. Sci. Total Environ. 409, 4899–4916 (2011).
Chen, D., Huang, H., Hu, M. & Dahlgren, R. A. Influence of lag effect, soil release, and climate change on watershed anthropogenic nitrogen inputs and riverine export dynamics. Environ. Sci. Technol. 48, 5683–5690 (2014).
Jensen, P. N. (ed.) Estimation of Nitrogen Concentrations from Root Zone to Marine Areas Around the Year 1900 Scientific Report No. 241 (Danish Centre for Environment and Energy, 2017).
Liu, J., Van Meter, K. J., McLeod, M. M. & Basu, N. B. Checkered landscapes: hydrologic and biogeochemical nitrogen legacies along the river continuum. Environ. Res. Lett. 16, 115006 (2021).
Byrnes, D. K., Van Meter, K. J. & Basu, N. B. Trajectories Nutrient Dataset for Nitrogen (TREND-nitrogen) (PANGAEA, 2020); https://doi.org/10.1594/PANGAEA.917583
Byrnes, D. K., Van Meter, K. J., & Basu, N. B. Long-term shifts in U.S. nitrogen sources and sinks revealed by the new TREND-nitrogen data set (1930–2017) Global Biogeochem. Cycles 34, e2020GB006626 (2020).
Sousa, M. R., Jones, J. P., Frind, E. O. & Rudolph, D. L. A simple method to assess unsaturated zone time lag in the travel time from ground surface to receptor. J. Contam. Hydrol. 144, 138–151 (2013).
This work was financed in part through Natural Sciences and Engineering Research Council of Canada (NSERC) in the frame of the collaborative Water JPI international consortium pilot call under the project name ‘Legacies of Agricultural Pollutants (LEAP): Integrated Assessment of Biophysical and Socioeconomic Controls on Water Quality Agroecosystems’ (N.B.B., K.J.V.M., R. Brouwer, R. Bhattacharya, M.C.C., G.D., B.H.J., J.J., S.B.O. and P.V.C.) and by Lake Futures Project under the Global Water Futures umbrella, and provided through the Canada First Research Excellence Fund (N.B.B., P.V.C., R. Brouwer and R. Bhattacharya). N.B.B. was also supported by a University Research Chair appointment and by an NSERC Discovery Grant. K.J.V.M. was also supported by startup funds at The Pennsylvania State University. D.K.B. was supported by the NSERC Alexander Graham Bell Canada Graduate Scholarship.
The authors declare no competing interests.
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Basu, N.B., Van Meter, K.J., Byrnes, D.K. et al. Managing nitrogen legacies to accelerate water quality improvement. Nat. Geosci. 15, 97–105 (2022). https://doi.org/10.1038/s41561-021-00889-9