Geo-Marine Letters

, Volume 37, Issue 2, pp 179–192 | Cite as

Estuary-type circulation as a factor sustaining horizontal nutrient gradients in freshwater-influenced coastal systems

  • Richard Hofmeister
  • Götz Flöser
  • Markus Schartau


Estuary-type circulation is a residual circulation in coastal systems with horizontal density gradients. It drives the accumulation of suspended particulate matter in coastal embayments where density gradients are sustained by some freshwater inflow from rivers. Ebenhöh et al. (Ecol Model 174(3):241–252, 2004) found that shallow water depth can explain nutrient gradients becoming established towards the coast even in the absence of river inflow. The present study follows their concept and investigates the characteristic transport of organic matter towards the coast based on idealised scenarios whereby an estuary-type circulation is maintained by surface freshwater fluxes and pronounced shoaling towards the coast. A coupled hydrodynamical and biogeochemical model is used to simulate the dynamics of nutrient gradients and to derive budgets of organic matter flux for a coastal transect. Horizontal nutrient gradients are considered only in terms of tidal asymmetries of suspended matter transport. The results show that the accumulation of organic matter near the coast is not only highly sensitive to variations in the sinking velocity of suspended matter but is also noticeably enhanced by an increase in precipitation. This scenario is comparable with North Sea conditions. By contrast, horizontal nutrient gradients would be reversed in the case of evaporation-dominated inverse estuaries (cf. reverse gradients of nutrient and organic matter concentrations). Credible coastal nutrient budget calculations are required for resolving trends in eutrophication. For tidal systems, the present results suggest that these calculations require an explicit consideration of freshwater flux and asymmetries in tidal mixing. In the present case, the nutrient budget for the vertically mixed zone also indicates carbon pumping from the shelf sea towards the coast from as far offshore as 25 km.


Suspended Particulate Matter Dissolve Inorganic Carbon Particulate Organic Matter Dissolve Inorganic Nitrogen Horizontal Gradient 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



The work of Richard Hofmeister has been funded by the Lower Saxony Ministries for Science and Culture (MWK) and the Ministry of Environment, Energy and Environmental Protection (MU) through the project WIMO and by the German Federal Ministry of Education and Research (BMBF) through the project MOSSCO. We thank Karsten Bolding and Jorn Bruggeman for maintaining the open-source modelling software FABM, GOTM and GETM. Constructive assessments by three reviewers are acknowledged.

Compliance with ethical standards

Conflict of interest

The authors declare that there is no conflict of interest with third parties.

Supplementary material

367_2016_469_MOESM1_ESM.pdf (430 kb)
ESM 1 (PDF 429 kb)


  1. Alldredge AL, Passow U, Logan BE (1993) The abundance and significance of a class of large, transparent organic particles in the ocean. Deep Sea Res I Oceanogr Res Pap 40(6):1131–1140CrossRefGoogle Scholar
  2. Becherer J, Burchard H, Flöser G, Mohrholz V, Umlauf L (2011) Evidence of tidal straining in well-mixed channel flow from micro-structure observations. Geophys Res Lett 38(17):L17611. doi: 10.1029/2011GL049005 CrossRefGoogle Scholar
  3. Bruggeman J, Bolding K (2014) A general framework for aquatic biogeochemical models. Environ Model Software 61:249–265. doi: 10.1016/j.envsoft.2014.04.002 CrossRefGoogle Scholar
  4. Burchard H, Badewien TH (2015) Thermohaline residual circulation of the Wadden Sea. Ocean Dyn 65(12):1717–1730CrossRefGoogle Scholar
  5. Burchard H, Hetland RD (2010) Quantifying the contributions of tidal straining and gravitational circulation to residual circulation in periodically stratified tidal estuaries. J Phys Oceanogr 40(6):1243–1262. doi: 10.1175/2010JPO4270.1 CrossRefGoogle Scholar
  6. Burchard H, Bolding K, Villarreal MR (2004) Three-dimensional modelling of estuarine turbidity maxima in a tidal estuary. Ocean Dyn 54:250–265CrossRefGoogle Scholar
  7. Burchard H, Flöser G, Staneva JV, Badewien TH, Riethmüller R (2008) Impact of density gradients on net sediment transport into the Wadden Sea. J Phys Oceanogr 38(3):566–587. doi: 10.1175/2007JPO3796.1 CrossRefGoogle Scholar
  8. Burchard H, Schuttelaars HM, Geyer WR (2013) Residual sediment fluxes in weakly-to-periodically stratified estuaries and tidal inlets. J Phys Oceanogr 43(9):1841–1861CrossRefGoogle Scholar
  9. Burnett WC, Bokuniewicz H, Huettel M, Moore WS, Taniguchi M (2003) Groundwater and pore water inputs to the coastal zone. Biogeochemistry 66(1/2):3–33. doi: 10.1023/B:BIOG.0000006066.21240.53 CrossRefGoogle Scholar
  10. Cloern JE (1987) Turbidity as a control on phytoplankton biomass and productivity in estuaries. Cont Shelf Res 7:1367–1381CrossRefGoogle Scholar
  11. Deek A, Dähnke K, van Beusekom J, Meyer S, Voss M, Emeis K (2013) N2 fluxes in sediments of the Elbe Estuary and adjacent coastal zones. Mar Ecol Prog Ser 493:9–21. doi: 10.3354/meps10514 CrossRefGoogle Scholar
  12. Delaney ML (1998) Phosphorus accumulation in marine sediments and the oceanic phosphorus cycle. Glob Biogeochem Cycles 12(4):563–572. doi: 10.1029/98GB02263 CrossRefGoogle Scholar
  13. Dentener F, Drevet J, Lamarque JF, Bey I, Eickhout B, Fiore AM, Hauglustaine D, Horowitz LW, Krol M, Kulshrestha UC, Lawrence M, Galy-Lacaux C, Rast S, Shindell D, Stevenson D, Van Noije T, Atherton C, Bell N, Bergman D, Butler T, Cofala J, Collins B, Doherty R, Ellingsen K, Galloway J, Gauss M, Montanaro V, Müller JF, Pitari G, Rodriguez J, Sanderson M, Solmon F, Strahan S, Schultz M, Sudo K, Szopa S, Wild O (2006) Nitrogen and sulfur deposition on regional and global scales: a multimodel evaluation. Glob Biogeochem Cycles 20:GB4003. doi: 10.1029/2005GB002672 CrossRefGoogle Scholar
  14. Ebenhöh W, Kohlmeier C, Baretta J, Flöser G (2004) Shallowness may be a major factor generating nutrient gradients in the Wadden Sea. Ecol Model 174(3):241–252. doi: 10.1016/j.ecolmodel.2003.07.011 CrossRefGoogle Scholar
  15. Eckart C (1952) The propagation of water waves from deep to shallow water. Natl Bur Stand Circ 20:165–173Google Scholar
  16. Engel A, Thoms S, Riebesell U, Rochelle-Newall E, Zondervan I (2004) Polysaccharide aggregation as a potential sink of marine dissolved organic carbon. Nature 428(6986):929–932CrossRefGoogle Scholar
  17. Feser F, Weisse R, von Storch H (2001) Multi-decadal atmospheric modeling for Europe yields multi-purpose data. EOS Trans Am Geophys Union 82(28):305–310. doi: 10.1029/01EO00176 CrossRefGoogle Scholar
  18. Fettweis M, Francken F, Van den Eynde D, Verwaest T, Janssens J, Van Lancker V (2010) Storm influence on SPM concentrations in a coastal turbidity maximum area with high anthropogenic impact (southern North Sea). Cont Shelf Res 30(13):1417–1427. doi: 10.1016/j.csr.2010.05.001 CrossRefGoogle Scholar
  19. Flöser G, Riethmüller R, Nauw J, Burchard H (2013) Observational evidence for the general presence of estuarine circulation in the Wadden Sea. J Coast Res 65:1527–1532. doi: 10.2112/SI65-258.1 CrossRefGoogle Scholar
  20. Frank C, Schroeder F, Ebinghaus R, Ruck W (2006) A fast sequential injection system for the simultaneous determination of ammonia and phosphate. Microchim Acta 154:31–38. doi: 10.1007/s00604-006-0496-y CrossRefGoogle Scholar
  21. Gayer G, Dick S, Pleskachevsky A, Rosenthal W (2006) Numerical modeling of suspended matter transport in the North Sea. Ocean Dyn 56(1):62–77. doi: 10.1007/s10236-006-0070-5 CrossRefGoogle Scholar
  22. Geider RJ, MacIntyre HL, Kana TM (1998) A dynamic regulatory model of phytoplanktonic acclimation to light, nutrients, and temperature. Limnol Oceanogr 43(4):679–694CrossRefGoogle Scholar
  23. Geyer WR, MacCready P (2014) The estuarine circulation. Annu Rev Fluid Mech 46(1):175–197. doi: 10.1146/annurev-fluid-010313-141302 CrossRefGoogle Scholar
  24. Grasshoff K, Ehrhardt M, Kremling K (1999) Methods of seawater analysis, 3rd edn. Wiley-VCh, New YorkCrossRefGoogle Scholar
  25. Gräwe U, Wolff JO, Ribbe J (2010) Impact of climate variability on an east Australian bay. Estuar Coast Shelf Sci 86(2):247–257. doi: 10.1016/j.ecss.2009.11.020 CrossRefGoogle Scholar
  26. Grunwald M, Dellwig O, Kohlmeier C, Kowalski N, Beck M, Badewien TH, Kotzur S, Liebezeit G, Brumsack HJ (2010) Nutrient dynamics in a back barrier tidal basin of the Southern North Sea: time-series, model simulations, and budget estimates. J Sea Res 64(3):199–212. doi: 10.1016/j.seares.2010.02.008 CrossRefGoogle Scholar
  27. Hetzel Y, Pattiaratchi C, Lowe R (2013) Intermittent dense water outflows under variable tidal forcing in Shark Bay, Western Australia. Cont Shelf Res 66:36–48. doi: 10.1016/j.csr.2013.06.015 CrossRefGoogle Scholar
  28. Jay DA, Musiak JD (1994) Particle trapping in estuarine tidal flows. J Geophys Res 99(C10):20445–20461. doi: 10.1029/94JC00971 CrossRefGoogle Scholar
  29. Kondo J (1975) Air–sea bulk transfer coefficients in diabetic conditions. Bound Layer Meteorol 9:91–112CrossRefGoogle Scholar
  30. Kumar N, Voulgaris G, Warner JC, Olabarrieta M (2012) Implementation of the vortex force formalism in the coupled ocean-atmosphere-wave-sediment transport (COAWST) modeling system for inner shelf and surf zone applications. Ocean Model 47:65–95. doi: 10.1016/j.ocemod.2012.01.003 CrossRefGoogle Scholar
  31. Lenhart H-J, Mills DK, Baretta-Bekker H, van Leeuwen SM, van der Molen J, Baretta JW, Blaas M, Desmit X, Kühn W, Lacroix G, Los HJ, Ménesguen A, Neves R, Proctor R, Ruardij P, Skogen MD, Vanhoutte-Brunier A, Villars MT, Wakelin SL (2010) Predicting the consequences of nutrient reduction on the eutrophication status of the North Sea. J Mar Syst 81:148–170. doi: 10.1016/j.jmarsys.2009.12.014 CrossRefGoogle Scholar
  32. Lucotte M, D’Anglejan B (1983) Forms of phosphorus and phosphorus-iron relationships in the suspended matter of the St. Lawrence Estuary. Can J Earth Sci 20:1880–1890CrossRefGoogle Scholar
  33. Maerz J, Hofmeister R, van der Lee EM, Gräwe U, Riethmüller R, Wirtz KW (2016) Evidence for a maximum of sinking velocities of suspended particulate matter in a coastal transition zone. Biogeosci Discuss. doi: 10.5194/bg-2015-667 Google Scholar
  34. Onken R, Riethmüller R (2010) Determination of the freshwater budget of tidal flats from measurements near a tidal inlet. Cont Shelf Res 30(8):924–933. doi: 10.1016/j.csr.2010.02.004 CrossRefGoogle Scholar
  35. Painting S, Foden J, Forster R, van der Molen J, Aldridge J, Best M, Jonas P, Hydes D, Walsham P, Webster L, Gubbins M, Heath M, McGovern E, Vincent C, Gowen R, O’Boyle S (2013) Impacts of climate change on nutrient enrichment. MCCIP Sci Rev 2013:219–235. doi: 10.14465/2013.arc23.219-235 Google Scholar
  36. Petersen W, Schroeder F, Bockelmann F-D (2011) FerryBox - Application of continuous water quality observations along transects in the North Sea. Ocean Dyn 61(10):1541–1554. doi: 10.1007/s10236-011-0445-0 CrossRefGoogle Scholar
  37. Pritchard D, Hogg A (2003) Cross-shore sediment transport and the equilibrium morphology of mudflats under tidal currents. J Geophys Res 108:3313. doi: 10.1029/2002JC001570 CrossRefGoogle Scholar
  38. Puls W, Bernem KH, Eppel D, Kapitza H, Pleskachevsky A, Riethmüller R, Vaessen B (2011) Prediction of benthic community structure from environmental variables in a soft-sediment tidal basin (North Sea). Helgol Mar Res 66(3):345–361. doi: 10.1007/s10152-011-0275-y CrossRefGoogle Scholar
  39. Schartau M, Engel A, Schröter J, Thoms S, Völker C, Wolf-Gladrow D (2007) Modelling carbon overconsumption and the formation of extracellular particulate organic carbon. Biogeosci Discuss 4(1):13–67CrossRefGoogle Scholar
  40. Simpson JH, Brown J, Matthews J, Allen G (1990) Tidal straining, density currents, and stirring in the control of estuarine stratification. Estuaries 13(2):125–132. doi: 10.2307/1351581 CrossRefGoogle Scholar
  41. Soulsby RL (1997) Dynamics of marine sands. Thomas Telford, LondonGoogle Scholar
  42. Stacey MT, Brennan ML, Burau JR, Monismith SG (2010) The tidally averaged momentum balance in a partially and periodically stratified estuary. J Phys Oceanogr 40(11):2418–2434. doi: 10.1175/2010JPO4389.1 CrossRefGoogle Scholar
  43. Stanev EV, Dobrynin M, Pleskachevsky A, Grayek S, Günther H (2008) Bed shear stress in the southern North Sea as an important driver for suspended sediment dynamics. Ocean Dyn 59(2):183–194. doi: 10.1007/s10236-008-0171-4 CrossRefGoogle Scholar
  44. Thomas H, Bozec Y, de Baar HJW, Elkalay K, Frankignoulle M, Schiettecatte LS, Kattner G, Borges AV (2005) The carbon budget of the North Sea. Biogeosciences 2(1):87–96. doi: 10.5194/bg-2-87-2005 CrossRefGoogle Scholar
  45. van Beusekom J, Brockmann UH, Hesse KJ, Hickel W, Poremba K, Tillmann U (1999) The importance of sediments in the transformation and turnover of nutrients and organic matter in the Wadden Sea and German Bight. German J Hydrogr 51(2):245–266. doi: 10.1007/BF02764176 Google Scholar
  46. van Beusekom J, Loebl M, Martens P (2009) Distant riverine nutrient supply and local temperature drive the long-term phytoplankton development in a temperate coastal basin. J Sea Res 61(1-2):26–33. doi: 10.1016/j.seares.2008.06.005 CrossRefGoogle Scholar
  47. van der Molen J, Bolding K, Greenwood N, Mills DK (2009) A 1-D vertical multiple grain size model of suspended particulate matter in combined currents and waves in shelf seas. J Geophys Res 114:F01030. doi: 10.1029/2008JF001150 Google Scholar
  48. van Engeland T, Soetaert K, Knuijt A, Laane R, Middelburg J (2010) Dissolved organic nitrogen dynamics in the North Sea: a time series analysis (1995-2005). Estuar Coast Shelf Sci 89(1):31–42. doi: 10.1016/j.ecss.2010.05.009 CrossRefGoogle Scholar
  49. van Leeuwen S, Tett P, Mills D, van der Molen J (2015) Stratified and nonstratified areas in the North Sea: long-term variability and biological and policy implications. J Geophys Res Oceans 120:4670–4686. doi: 10.1002/2014JC010485 CrossRefGoogle Scholar
  50. Winter C, Herrling G, Bartholomä A, Capperucci R, Callies U, Heipke C, Schmidt A, Hillebrand H, Reimers C, Bremer P, Weiler R (2014) Scientific concepts for monitoring the ecological state of German coastal seas (in German). Wasser und Abfall 07–08(2014):21–26. doi: 10.1365/s35152-014-0685-7 CrossRefGoogle Scholar
  51. Wu Z, Zhou H, Zhang S, Liu Y (2013) Using 222Rn to estimate submarine groundwater discharge (SGD) and the associated nutrient fluxes into Xiangshan Bay, East China Sea. Mar Pollut Bull 73(1):183–91. doi: 10.1016/j.marpolbul.2013.05.024 CrossRefGoogle Scholar
  52. Young IR, Verhagen LA (1996) The growth of fetch limited waves in water of finite depth. Part 1. Total energy and peak frequency. Coast Eng 29(1-2):47–78. doi: 10.1016/S0378-3839(96)00006-3 CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  • Richard Hofmeister
    • 1
    • 2
  • Götz Flöser
    • 1
  • Markus Schartau
    • 3
  1. 1.Helmholtz-Zentrum GeesthachtInstitute of Coastal ResearchGeesthachtGermany
  2. 2.Institute of Hydrobiology and Fisheries ScienceUniversity of HamburgHamburgGermany
  3. 3.GEOMAR Helmholtz Centre for Ocean ResearchKielGermany

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