| Title | Nitrogen budget of Lago Maggiore: The relative importance of atmospheric deposition and catchment sources. |
| Abstract | Hydrological and chemical data of 1996 and 1997 are used to evaluate the relative contributions of atmospheric deposition and urban/industrial wastewaters to the nitrogen budget of Lago Maggiore. The atmospheric load of nitrogen was about 80% of the total input to the lake, with negligible variations in dry (1997) and wet (1996) years. A comparison of the two study years with the yearly N budgets evaluated from 1978 to 1998, showed that the N load was higher with increasing amounts of precipitation/water inflow. Soils and vegetation act as N sinks; the % retention varies between 40-60% for the forested catchments with low population density in the central-northern part of the basin, to values close to zero or even negative in the south, indicating a net leaching from the soils. The Traaen & Stoddard (1995) approach revealed that all the catchments of the major inflowing rivers were oversaturated with nitrogen. The long-term trend of nitrogen concentrations in Lago Maggiore (1955-99) is analogous to the trend for atmospheric deposition (1975-99), which is related to emissions of nitrogen oxides and ammonia in the atmosphere. The relationships between the present N load and in-lake concentrations are discussed using a budget model, which is also used to infer the pristine load of N. The close relationships between N trends in lakes Maggiore, Como and Iseo, and the geographical and anthropogenic features common to their catchments, suggest that the results obtained for Lago Maggiore can be extended to a wider area. |
| Source | Journal of limnology (Testo stamp.) 60 (1), pp. 27–40 |
| Keywords | nitrogenatmospheric depositionwater chemistrywatershed |
| Journal | Journal of limnology (Testo stamp.) |
| Editor | Istituto per lo Studio degli Ecosistemi., Verbania Pallanza, Italia |
| Year | 2001 |
| Type | Articolo in rivista |
| Authors | Mosello, Rosario; Barbieri, Alberto; Brizzio, Maria Cristina; Calderoni, Alcide; Marchetto, Aldo; Passera, Stefania; Rogora, Michela; Tartari, Gabriele |
| Text | 407796 2001 ISI Web of Science WOS BCI200300001336 nitrogen atmospheric deposition water chemistry watershed Nitrogen budget of Lago Maggiore The relative importance of atmospheric deposition and catchment sources. Mosello, Rosario; Barbieri, Alberto; Brizzio, Maria Cristina; Calderoni, Alcide; Marchetto, Aldo; Passera, Stefania; Rogora, Michela; Tartari, Gabriele C.N.R. Istituto Italiano di Idrobiologia, L.go Tonolli 50, 28922, Verbania Pallanza, Italy Hydrological and chemical data of 1996 and 1997 are used to evaluate the relative contributions of atmospheric deposition and urban/industrial wastewaters to the nitrogen budget of Lago Maggiore. The atmospheric load of nitrogen was about 80% of the total input to the lake, with negligible variations in dry 1997 and wet 1996 years. A comparison of the two study years with the yearly N budgets evaluated from 1978 to 1998, showed that the N load was higher with increasing amounts of precipitation/water inflow. Soils and vegetation act as N sinks; the % retention varies between 40 60% for the forested catchments with low population density in the central northern part of the basin, to values close to zero or even negative in the south, indicating a net leaching from the soils. The Traaen Stoddard 1995 approach revealed that all the catchments of the major inflowing rivers were oversaturated with nitrogen. The long term trend of nitrogen concentrations in Lago Maggiore 1955 99 is analogous to the trend for atmospheric deposition 1975 99 , which is related to emissions of nitrogen oxides and ammonia in the atmosphere. The relationships between the present N load and in lake concentrations are discussed using a budget model, which is also used to infer the pristine load of N. The close relationships between N trends in lakes Maggiore, Como and Iseo, and the geographical and anthropogenic features common to their catchments, suggest that the results obtained for Lago Maggiore can be extended to a wider area. 60 Published version Articolo in rivista Istituto per lo Studio degli Ecosistemi. 1129 5767 Journal of limnology Testo stamp. Journal of limnology Testo stamp. J. limnol. Testo stamp. Journal of limnology. Testo stamp. rosario.mosello MOSELLO ROSARIO aldo.marchetto MARCHETTO ALDO michela.rogora ROGORA MICHELA gabriele.tartari TARTARI GABRIELE |
