| Title | Trends in nitrogen deposition and leaching in acid-sensitive streams in Europe |
| Abstract | Long-term records of nitrogen in deposition and streamwater were analysed at 30 sites covering major acid sensitive regions in Europe. Large regions of Europe have received high inputs of inorganic nitrogen for the past 20-30 years, with an approximate 20% decline in central and northern Europe during the late 1990s. Nitrate concentrations in streamwaters are related to the amount of N deposition. All sites with less than 10 kgN ha(-1) yr(-1) deposition have low concentrations of nitrate in streamwater, whereas all sites receiving > 25 kgN ha(-1) yr(-1) have elevated concentrations. Very few of the sites exhibit significant trends in nitrate concentrations; similar analyses on other datasets also show few significant trends. Nitrogen saturation is thus a process requiring many decades, at least at levels of N deposition typical for Europe. Declines in nitrate concentrations at a few sites may reflect recent declines in N deposition. The overall lack of significant trends in nitrate concentrations in streams in Europe may be the result of two opposing factors. Continued high deposition of nitrogen (above the 10 kgN ha(-1) yr(-1) threshold) should tend to increase N saturation and give increased nitrate concentrations in run-off, whereas the decline in N deposition over the past 5-10 years in large parts of Europe should give decreased nitrate concentrations in run-off. Short and long-term variations in climate affect nitrate concentrations in streamwater and, thus, contribute "noise" which masks long-term trends. Empirical data for geographic pattern and long-term trends in response of surface waters to changes in N deposition set the premises for predicting future contributions of nitrate to acidification of soils and surface waters. Quantification of processes governing nitrogen retention and loss in semi-natural terrestrial ecosystems is a scientific challenge of increasing importance. |
| Source | Hydrology and earth system sciences 5 (3), pp. 299–310 |
| Keywords | FORESTED CATCHMENTRUNOFF CHEMISTRYCLEAN RAINPROJECTACIDIFICATIONECOSYSTEMSRECOVERYWATERSINPUT |
| Journal | Hydrology and earth system sciences |
| Editor | Copernicus Publ., Göttingen, Germania |
| Year | 2001 |
| Type | Articolo in rivista |
| Authors | Wright, RF (Wright, RF); Alewell, C (Alewell, C); Cullen, JM (Cullen, JM); Evans, CD (Evans, CD); Marchetto, A (Marchetto, A); Moldan, F (Moldan, F); Prechtel, A (Prechtel, A); Rogora, M (Rogora, M) |
| Text | 252374 2001 ISI Web of Science WOS 000172782600004 FORESTED CATCHMENT RUNOFF CHEMISTRY CLEAN RAIN PROJECT ACIDIFICATION ECOSYSTEMS RECOVERY WATERS INPUT Trends in nitrogen deposition and leaching in acid sensitive streams in Europe Wright, RF Wright, RF ; Alewell, C Alewell, C ; Cullen, JM Cullen, JM ; Evans, CD Evans, CD ; Marchetto, A Marchetto, A ; Moldan, F Moldan, F ; Prechtel, A Prechtel, A ; Rogora, M Rogora, M 1 Norwegian Inst Water Res, N 0411 Oslo, Norway 2 Univ Bayreuth, BITOK, Inst Terr Ecosyst Res, D 95440 Bayreuth, Germany 3 Ctr Ecol Hydrol, Wallingford OX10 8BB, Oxon, England 4 Ist Italiano Idrobiol, CNR, I 28922 Verbania, VB, Italy 5 Swedish Environm Res Inst, IVL, S 40258 Gothenburg, Sweden Long term records of nitrogen in deposition and streamwater were analysed at 30 sites covering major acid sensitive regions in Europe. Large regions of Europe have received high inputs of inorganic nitrogen for the past 20 30 years, with an approximate 20% decline in central and northern Europe during the late 1990s. Nitrate concentrations in streamwaters are related to the amount of N deposition. All sites with less than 10 kgN ha 1 yr 1 deposition have low concentrations of nitrate in streamwater, whereas all sites receiving > 25 kgN ha 1 yr 1 have elevated concentrations. Very few of the sites exhibit significant trends in nitrate concentrations; similar analyses on other datasets also show few significant trends. Nitrogen saturation is thus a process requiring many decades, at least at levels of N deposition typical for Europe. Declines in nitrate concentrations at a few sites may reflect recent declines in N deposition. The overall lack of significant trends in nitrate concentrations in streams in Europe may be the result of two opposing factors. Continued high deposition of nitrogen above the 10 kgN ha 1 yr 1 threshold should tend to increase N saturation and give increased nitrate concentrations in run off, whereas the decline in N deposition over the past 5 10 years in large parts of Europe should give decreased nitrate concentrations in run off. Short and long term variations in climate affect nitrate concentrations in streamwater and, thus, contribute noise which masks long term trends. Empirical data for geographic pattern and long term trends in response of surface waters to changes in N deposition set the premises for predicting future contributions of nitrate to acidification of soils and surface waters. Quantification of processes governing nitrogen retention and loss in semi natural terrestrial ecosystems is a scientific challenge of increasing importance. 5 Trends in nitrogen deposition and leaching in acid sensitive streams in Europe Wright_etal_HESS_2001.pdf Articolo in rivista Copernicus Publ. 1027 5606 Hydrology and earth system sciences Hydrology and earth system sciences Hydrol. earth syst. sci. Hydrology and earth system sciences. HESS Gottingen. Print Hydrology and earth system sciences Print aldo.marchetto MARCHETTO ALDO michela.rogora ROGORA MICHELA |
