The North Sea: source or sink for nitrogen and phosphorus to the Atlantic Ocean?
Tóm tắt
Annual nitrogen and phosphorus budgets for the whole North Sea taking into account the most recent data available were established. The area considered has a total surface of approximately 700,000 km2 and corresponds to the definition by OSPARCOM (Oslo and Paris Commission) with the exclusion of the Skagerrak and Kattegat areas. Input and output fluxes were determined at the marine, atmospheric, sediment and continental boundaries, and riverine inputs based on river flows and nutrient concentrations at the river–estuary interface were corrected for possible estuarine retention. The results showed that the North Sea is an extremely complex system subjected to large inter-annual variability of marine water circulation and freshwater land run-off. Consequently, resulting total N (TN) and P (TP) fluxes are extremely variable from 1 year to another and this has an important influence on the budget of these elements. Total inputs to the North Sea are 8870 ± 4860 kT N year−1 and 494 ± 279 kT P year−1. Denitrification is responsible for the loss of 23 ± 7% of the TN inputs while sediment burial is responsible for the retention of only of 2 ± 2% of the TP input. For TN, due to the large variability on marine and estuarine fluxes, and to the uncertainty related to the denitrification rate, it was concluded that the North Sea could either be a source (1930 kT N year−1) or a sink (1700 kT N year−1) for the waters of the North Atlantic Ocean. For TP it was concluded that the North Sea is mostly a source (−4 to 52 kT P year−1) for the waters of the North Atlantic Ocean.
Tài liệu tham khảo
AESN 1994. Agence de l'eau Seine-Normandie, Service Maritime de la Seine-Maritime (3ème section), Service de la navigation de la Seine (4ème section), Subdivision de la Navigation et de lutte contre la pollution. Reconnaissances Hydrologiques des 17 et 18 janvier, 16 et 17 mars, 16 et 17 mai, 11 et 12 juillet, 7 et 8 septembre, 22 et 23 novembre 1994. Cellule antipollution de la Seine, Rouen, France.
Barnes J. and Owens N.J.P. 1998. Denitrification and nitrous oxide concentrations in the Humber Estuary, UK, and adjacent coastal zones. Mar. Pollut. Bull. 37: 247–260.
Billen G. and Servais P. 1991. Modélisation du transport de pollutants par l'estuaire de l'Escaut, cas du phosphore. In: Unité de Gestion du Modèle Mathématique de la Mer du Nord et de l'estuaire de l'escaut, Ministère de la Santé Publique et de l'Environment. Bruxelles, Belgique.
Brion N., Billen G., Guezennec L. and Ficht A. 2000. Distribution of nitrifying activity in the Seine River (France) and its estuary. Estuaries 23(5): 669–682.
Cornell S., Rendell A. and Jickells T. 1995. Atmospheric inputs of dissolved organic nitrogen to the oceans. Nature 243–246.
De Vries A. and Klavers H. 1994. Riverine fluxes of pollutants: monitoring strategy first, calculation methods second. Eur. Water Pollut. Control 4: 12–17.
Fifth North Sea Conference 2002. Progress Report, Fifth International Conference on the protection of the North Sea, 20–21 March 2002. Bergen, Norway. Nilsen H.-G., Aarefjord H., Overland S. and Rukke J. (eds) Ministry of the Environment, Oslo, Norway, 210 p.
Goosen N.K., van Rijswijk P. and Brockmann U. 1995. Comparison of heterotrophic bacterial production rates in early spring in the turbid estuaries of the Scheldt and Elbe. Hydrobiologia 311: 31–42.
Grabemann H.J., Grabemann I., Herbers D., Loebel P. and Müller A. 1999. Hydrodynamik and Gewässergüte der Unterweser vor dem Hintergrund unterschiedlicher Nutzungen. In: Scirmer M. and Schuchardt B. (eds). Die Unterweser als Natur-, Lebens-und Wirtshaftsraum – Eine querschnittsorientierte Zustandserfassung. Bremen, Germany, pp. 13–65.
Heip C. and Herman P.M.J. 1995. Major biological processes in European tidal estuaries: a synthesis of the Jeep-92 Project. Hydrobiologia 311: 1–7.
Hydes D.J., Kelly-Gerreyn B.A., Le Gall A.C. and Proctor R. 1999. The balance of supply of nutrients and demands of biological production and denitrification in a temperate latitude shelf sea – a treatment of the southern North Sea as an extended estuary. Mar. Chem. 68: 117–131.
Kieskamp W.M., Lohse L., Epping E. and Helder W. 1991. Seasonal variation of denitrification rates and nitrous oxide fluxes in intertidal sediments of the western Wadden Sea. Mar. Ecol. Prog. Ser. 72: 145–151.
Laane R.W.P.M. 1992. Background concentrations of natural compounds. Report DGW-92.033. Tidal water division, Directorate-General of Public Works and Water Management, Ministry of Transport, Public Works and Water Management. The Netherlands, pp. 17–26.
Laane R.W.P.M., Svendsen E., Radach G., Groeneveld G., Damm P., Pätsch J., Danielssen D.S., Føyn L., Skogen M., Ostrowski M. and Kramer K.J.M. 1996. Variability in fluxes of nutrients (N, P, Si) into the North Sea from Atlantic Ocean and Skagerrak. German J. of Hydrogr. 48: 401–419.
Law C.S. and Owens N.J.P. 1990. Denitrification and nitrous oxide in the North Sea. Netherlands J. of Sea Res. 25: 65–74.
Levy II H. and Moxim J.M. 1989. Simulated global distribution and deposition of reactive nitrogen emitted by fossil fuel combustion. Tellus 41B: 256–271.
Lipshultz F. and Owens N.J.P. 1996. An assessment of nitrogen fixation as a source of nitrogen to the North Atlantic Ocean. Biogeochemistry 35: 261–274.
Lohse L., Malschaert H.F.P., Slomp C., Helder W. and van Raaphorst W. 1993. Nitrogen cycling in North Sea sediments: interaction of denitrification and nitrification in offshore and coastal areas. Mar. Ecol. Prog. Ser. 101: 283–296.
Lohse L., Malschaert H.F.P., Slomp C., Helder W. and van Raaphorst W. 1995. Sediment-water fluxes of inorganic nitrogen compounds along the transport route of organic matter in the North Sea. Ophelia 41: 173–197.
Michaels A.F., Olson D., Sarmiento J.L., Ammerman J.W., Fanning K., Jahnke R., Knap A.H., Lipschultz F., Prospero J.M. 1996. Inputs, losses and transformation of nitrogen and phosphorus in the pelagic North Atlantic Ocean. Biogeochemistry 35: 181–226.
Middelburg J.J. and Nieuwenhuize J. 2000. Uptake of dissolved inorganic nitrogen in turbid, tidal estuaries. Mar. Ecol. Prog. Ser. 192: 79–88.
Nixon S.W., Ammermann J.W., Atkinson L.P., Berounsky V.M., Billen G., Boicourt W.C., Boynton W.R., Church T.M., Ditoro D.M., Elmgren R., Gaeber J.H., Giblin A.E., Jahnke R.A., Owens N.J.P., Pilson M.E.Q. and Seitzinger S.P. 1996. The fate of nitrogen and phosphorus at the land–sea margin of the North Atlantic Ocean. Biogeochemistry 35: 141–180.
Ohlendieck U., Stuhr A. and Siegmund H. 2000. Nitrogen fixation by diazotrophic cyanobacteria in the Baltic sea and transfer of the newly fixed nitrogen to picoplankton organisms. J. Mar. Syst. 25: 213–219.
OSPARCOM 1992. Data report on riverine and direct inputs of contaminants to the waters of the Paris convention in 1990.
OSPARCOM 1994. Data report on riverine and direct inputs of contaminants to the maritime area of the Paris convention in 1991.
OSPARCOM 1995a. Data report on riverine and direct inputs of contaminants to the maritime area of the Paris convention in 1992.
OSPARCOM 1995b. Data report on riverine and direct inputs of contaminants to the maritime area of the Paris convention in 1993.
OSPARCOM 1996. Data report on the comprehensive study of riverine inputs and direct discharges (RID) in 1994.
OSPARCOM 1997. Data report on the comprehensive study of riverine inputs and direct discharges (RID) in 1995.
OSPARCOM 1998a. Data report on the comprehensive study of riverine inputs and direct discharges (RID) in 1996.
OSPARCOM 1998b. Summary report of the comprehensive study on riverine inputs and direct discharges (RID) in 1990–1995. Environmental assessment and monitoring committee (ASMO), 114 pp.
OSPARCOM 2000a. Data report on the comprehensive study of riverine inputs and direct discharges (RID) in 1997.
OSPARCOM 2000b. Data report on the comprehensive study of riverine inputs and direct discharges (RID) in 1998.
OSPARCOM 2000c. Quality Status Report 2000. Region II Greater North Sea. Published by OSPAR Commission, London. Can be free downloaded at (http://www.ospar.org/).
Otto L., Zimmerman J.T.F., Furnes G.K., Murk M., Saetre R. and Becker G. 1990. Review of the physical oceanography of the North Sea. Netherlands J. Sea Res. 26: 161–328.
Radach G. 1992. Ecosystem functioning in the German Bight under continental nutrient inputs by rivers. Estuaries 15: 477–496.
Radach G. and Lenhart H.J. 1995. Nutrient dynamics in the North Sea: fluxes and budgets in the water column derived from ERSEM. Netherlands J. Sea Res. 33: 301–335.
Radach G., Pätsch J., Gekeler J. and Herbig K. 1995. Annual cycles of nutrients and chlorophyll in the North Sea. Technical report in 2 volumes. Berichte aus dem zentrum für meeres und klimaforschung, Reihe B: Ozeanographie 20: 370 p.
Rahm L., Jönsson A. and Wulff F. 2000. Nitrogen fixation in the Baltic proper: an empirical study. J. Mar. Syst. 25: 239–248.
Rolff C. 2000. Seasonal variation of d13C and d15N of size-fractionated plankton at a coastal station in the northern Baltic proper. Mar. Ecol. Prog. Series 203: 47–65.
Sanders R.J., Jickells T., Malcolm S., Brown J., Kirkwood D., Reeve A., Taylor J., Horrobin T. and Ashcroft C. 1997. Nutrient fluxes through the Humber estuary. J. Sea Res. 37: 3–23.
Schroeder F., Wiltshire K.H., Klages D., Mathieu B., Blöcker G. and Knauth H.D. 1996. Nitrogen and oxygen processes in sediments of the Elbe estuary. Arch. Hydrobiol. 110: 311–328.
Seitzinger S.P. and Giblin A.E. 1996. Estimating denitrification in North Atlantic continental shelf sediments. Biogeochemistry 35: 235–274.
Smith S.V., Boudreau P.R. and Ruardij P. 1997. NP budget for the southern North Sea. LOICZ paper. http://data.ecolgy.su.se/MNODE/Europe?NorthSea/NORTHSEA.htm
Van Beusekom J.E.E. and de Jonge V.N. 1998. Retention of phosphorus and nitrogen in the Ems estuary. Estuaries 21(4A): 527–539.
van Boxtel A.M.J.V., von Köningslöw Mov and Tossings F.M. 1991. Atmospheric deposition of nutrients into the North Sea: assessment of possible effects on algae growth. Geosense B.V. by order of the Ministry of Public Works and Transport. North Sea Directorate, The Netherlands, 60 p.
van Raaphorst W., Kloosterhuis H.T., Cramer A. and Bakker K.J.M. 1990. Nutrient early diagenesis in the sediments of the Dogger Bank area, North Sea: pore water results. Netherlands J. Sea Res. 26: 25–52.
van Raaphorst W., Kloosterhuis H.T., Berghuis E.M., Gieles A.J.M., Malschaert J.F.P. and Van Noort G.J. 1992. Nitrogen cycling in two types of sediments of the Southern North Sea (Frisian Front, Broadfourteens): field data and mesocosm results. Netherlands J. Sea Res. 28: 293–316.
Van Weering T.C.E., Berger G.W. and Kalf J. 1987. Recent sediment accumulation in the Skagerrak, Northeastern North Sea. Netherlands J. Sea Res. 21(3): 177–189.
Wolter K., Knauth H.D., Kock H.H. and Schroeder F. 1985. Nitrifikation und nitratatmung im wasser und sediment der Unterelbe. In: Fachgruppe Wasserchemie in der GDCH (ed) VCH Verlagsgesellschaft, Weinheim. Vom Wasser 65: 63–80.