%0 Journal Article %J J. Limnol. %D 2001 %T Nitrogen budget of Lago Maggiore: the relative importance of atmospheric deposition and catchment sources %A Mosello, R. , Calderoni A. , Marchetto A. , Brizzio M. C. , Rogora M. , Passera S. , Tartari. G. A. %K atmospheric deposition %K catchment %K Lago Maggiore %K nitrogen budget %K river water %X 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. %B J. Limnol. %V 60 %P 27-40 %1 General %0 Journal Article %J J. Limnol. %D 2008 %T The water chemistry of Northern Patagonian lakes and their nitrogen status in comparison with remote lakes in different regions of the globe %A Rogora, M %A Massaferro J. %A Marchetto A. %A Tartari G. A. %A Mosello R. %K Alps %K Antarctica %K atmospheric deposition %K Nepal %K Nitrate %X Eighteen small shallow lakes located in the Northern Patagonian Lake District, in southern South America, were sampled in 2001 and analysed for the main chemical variables (pH, conductivity, alkalinity, major ions and nutrients). The study lakes span a wide geographical and altitudinal range and belong partly to the Pacific and partly to the Atlantic watershed. The main aim of this study was to investigate the relationships between water chemistry and physical/geographical properties of these lakes. Secondly, the nitrogen content of the lakes was considered in detail, and results compared to those obtained in previous studies carried out in other remote areas of the globe (the Central Southern Alps in Italy, the Sierra da Estrela region in Portugal, the Svalbard Islands in the Arctic, the Khumbu-Himal region in Nepal, and the Terra Nova Bay area in Antarctica). In the Alps, lakes are characterised by markedly high nitrogen concentrations, manly as nitrate, due to the high inputs of nitrogen compounds from downwind sources like the Po Plain in Northern Italy. Conversely, lakes at remote locations such as the Andes, Antarctica and Himalaya are characterised by a low nitrogen content, mainly as organic nitrogen. This status is related to the limited atmospheric inputs of nitrogen affecting these regions. %B J. Limnol. %V 67 %P 75-86 %N 2 %1 General