, Volume 587, Issue 1, pp 5–18 | Cite as

Modelling the influence of nutrient loads on Portuguese estuaries

  • Sofia Saraiva
  • P. Pina
  • F. Martins
  • M. Santos
  • F. Braunschweig
  • R. Neves


The effects of implementing Directive 91/271/EEC of 21 May 1991 (Waste Water Treatment Plan Directive) and Directive 91/676/EEC of 12 December (Nitrates Directive) are analysed in 7 Portuguese estuaries (Minho, Lima, Douro, Mondego, Tagus, Sado and Guadiana) and two coastal lagoons (Ria de Aveiro and Ria Formosa), with a modelling approach. MOHID Water Modelling System was used to perform simulations with three nitrogen load scenarios for each system: a reference scenario, a 50% nitrate removal by agriculture scenario and another with a 100% nutrients removal by waste water treatment plants (WWTP). It is shown that the interaction between hydrodynamic and ecological processes is an important feature to study trophic problems in estuaries. Ecological processes such as primary production only occur inside the system if the residence time of water is high enough to enable organismal activity and if the adequate conditions are found (e.g. light, nutrients, temperature). From the model results it is possible to conclude: (i) in systems with short residence time a reduction in nutrient load will only produce a decrease in nutrient transit and will not affect the system’s global ecological status (e.g. Douro Estuary); (ii) in systems with long residence time the effects will range from significant, when primary production is mostly limited by nutrients (e.g. Ria de Aveiro), to non-significant, when primary production in the system is light-limited (e.g. Tagus Estuary).


Modelling European Directives Nutrient loads Coastal waters Primary production Eutrophication 



This research was made possible within the framework of a project of Portuguese National Water Institute (INAG) to evaluate water quality in Portuguese estuaries. The authors would also like to thank the contributions of two anonymous reviewers.


  1. Braunschweig, F., F. Martins, P. C. Leitão & R. J. Neves, 2003. A methodology to estimate renewal time scales in estuaries: the Tagus estuary case. Ocean Dynamics 53: 137–145.CrossRefGoogle Scholar
  2. Cunha, M., H. Coelho, R. J. Neves & P. C. Leitão, 2000. A numerical study of the Guadiana estuary. In Proceedings from the 3th Symposium on the Iberian Atlantic Margin. Universidade do Algarve, Faro, 27–28.Google Scholar
  3. Day, J. N., C. A. S. Hall, W. M. Kemp & A. Y. Arancibia, 1989. Estuarine ecology. Wiley, New York.Google Scholar
  4. De Jonge, V. N. & M. Elliott, 2001. Eutrophication. In Steele, J., S. Thorpe & K. Turekian (eds), Encyclopaedia of ocean sciences. Academic Press, London, 852–870.Google Scholar
  5. De Jonge, V. N., M. Elliott & E. Orive, 2002. Causes, historical development, effects and future challenges of a common environmental problem: eutrophication. Hydrobiologia 475–476: 1–19.CrossRefGoogle Scholar
  6. Deleersnijder, E., J.-M. Campin & E. J. M. Déles, 2001. The concept of age in marine modelling. I. Theory and preliminary model results. Journal of Marine Systems 28: 229–267.CrossRefGoogle Scholar
  7. EPA, 1985. Rates, constants and kinetics formulations in surface water quality modelling. 2nd edn. United States Environmental Protection Agency, Washington.Google Scholar
  8. Flindt, M. R., M. A. Pardal, A. I. Lillebø, I. Martins & J. C. Marques, 1999. Nutrient cycling and plant dynamics in estuaries: a brief review. Acta Oecologica 20: 237–248.CrossRefGoogle Scholar
  9. Grall, J. & L. Chauvaud, 2002. Marine eutrophication and benthos: the need for new approaches and concepts. Global Change Biology 8: 813–830.CrossRefGoogle Scholar
  10. Havens, K. E., J. Hauxwell, A. C. Tyler, S. Thomas, K. J. McGlathery, J. Cebrian, I. Valiela, A. D. Steinman & S. Hwang, 2001. Complex interactions between autotrophs in shallow marine and freshwater ecosystems: implications for community responses to nutrient stress. Environmental Pollution 113: 95–107.PubMedCrossRefGoogle Scholar
  11. Marsili-Libelli, S., 2003. Fuzzy prediction of the algae blooms in the Orbetello lagoon. Environmental Modelling and Software 19: 799–808.Google Scholar
  12. Martins, F., R. J. Neves, P. C. Leitão & A. Silva, 2001. 3D modelling in the Sado estuary using a new generic coordinate approach. Oceanologica Acta 24, S51-S62.CrossRefGoogle Scholar
  13. Martins, F., M. P. Reis, R. J. Neves, A. P. Cravo, A. Brito & A. Venâncio, 2004. Molluscan Shellfish bacterial contamination in Ria Formosa coastal lagoon: A modelling approach. Journal of Coastal Research, special issue 39.Google Scholar
  14. MOHID, 2004. Water Modelling System. Maretec—Instituto Superior Técnico, Lisbon. www.mohid.com.Google Scholar
  15. Nixon, S. W., 1995a. Enriching the sea to death. Scientific American. The Oceans, 48-53.Google Scholar
  16. Nixon, S. W., 1995b. Coastal marine eutrophication: a definition, social causes and future concerns. Ophelia 41: 199–220.Google Scholar
  17. Pina, P., 2001. An integrated approach to study the Tagus estuary water quality. [M.Sc Thesis]. Instituto Superior Técnico, Universidade Técnica de Lisboa, Lisbon.Google Scholar
  18. Pina, P., F. Brawnschweig, S. Saraiva, M. Santos & R. J. Neves, 2003. The role of physics controlling the eutrophication processes in estuaries. Thalassas 19: 141–143.Google Scholar
  19. Pina, P., J. P. Delfino, P. C. Leitão & R. J. Neves, 2000. An integrated approach to study the Tagus estuary water quality. Proceedings from the 3rd Symposium on the Iberian Atlantic Margin. Universidade do Algarve, Faro, 95–96.Google Scholar
  20. Portela, L., 1996. Modelação matemática de processos hidrodinâmicos e de qualidade da água no estuário do Tejo. [PhD Thesis]. Instituto Superior Técnico, Universidade Técnica de Lisbon.Google Scholar
  21. Schramm, W., 1999. Factors influencing seaweeds response to eutrophication: some results from EU-project EUMAC. Journal of Applied Phycology 11: 69–78.CrossRefGoogle Scholar
  22. Smith, V. H., G. D. Tilman & J. C. Nekola, 1999. Eutrophication: impacts of excess nutrients inputs on freshwater, marine, and terrestrial ecosystems. Environmental Pollution 100: 179–196.PubMedCrossRefGoogle Scholar
  23. Trancoso, A., S. Saraiva, L. Fernandes, P. Pina, P. Leitão & R. Neves, 2005. Modelling macroalgae using a 3D hydrodynamic-ecological model in a shallow, temperate estuary. Ecological Modelling 187: 232–246.CrossRefGoogle Scholar
  24. Valiela, I., 1995. Marine ecological processes. Springer-Verlag, New York.Google Scholar
  25. Villarreal, M. R., P. Montero, J. J. Tabuada, R. Prego, P. C. Leitão & P. Vicente, 2002. Hydrodynamic model study of the Ria de Pontevedra under estuarine conditions. Estuarine, Coastal and Shelf Science 54: 101–113.CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2007

Authors and Affiliations

  • Sofia Saraiva
    • 1
  • P. Pina
    • 1
  • F. Martins
    • 2
  • M. Santos
    • 1
  • F. Braunschweig
    • 1
  • R. Neves
    • 1
  1. 1.Instituto Superior TécnicoLisboaPortugal
  2. 2.Escola Superior de Tecnologia da Universidade do AlgarveFaroPortugal

Personalised recommendations