| Abstract | Several research programs monitoring atmospheric deposition have been launched in the Alpine countries in the last few decades. This paper uses data from previous and ongoing projects to: (i) investigate geographical variability in wet deposition chemistry over the Alps; (ii) assess temporal trends of the major chemical variables in response to changes in the atmospheric emission of pollutants; (iii) discuss the potential relationship between the status of atmospheric deposition and its effects on forest ecosystems in the alpine and subalpine area, focusing particularly on nitrogen input. We also present results of studies performed at a local level on specific topics such as long term changes in lead deposition and the role of occult deposition in total nitrogen input. The analysis performed here highlights the marked geographical variability of atmospheric deposition in the Alpine region. Apart from some evidence of geographically limited effects, due to local sources, no obvious gradients were identified in the major ion deposition. The highest ionic loads were recorded in areas in the foothills of the Alps, such as the pre-alpine area in North-Western Italy and the area of Canton Ticino, Switzerland. Trend analysis shows a widespread decrease in the acidity of precipitation in the last 15-20 years as a consequence of the reduced emission of S compounds. On the other hand, nitrate concentrations in rain have not changed so much, and ammonium has decreased significantly only at the Austrian sampling sites. The deposition of N is still well above the estimated critical loads of nutrient N at some forest sites in the alpine and subalpine areas, thus confirming the critical situation of both terrestrial and aquatic ecosystems regarding N inputs. Existing data highlights the importance of continuously monitoring atmospheric deposition chemistry in the Alpine area, taking account of acidifying elements, nutrients and other pollutants such as heavy metals and organic compounds. There is also a need for unifying sampling and analytical methods in order to obtain comparable data from the different regions of the Alps. |
| Text | 52914 2006 10.1007/s10750 005 1803 z ISI Web of Science WOS 000236780200003 precipitation chemistry wet deposition forest nitrogen trend An overview of atmospheric deposition chemistry over the Alps present status and long term trends Rogora M. 1 ; Mosello R. 1 ; Arisci S. 1 ; Brizzio M.C. 1 ; Barbieri A. 2 ; Balestrini R. 3 ; Waldner P. 4 ; Schmitt M. 4 ; Stahli M. 4 ; Thimonier A. 4 ; Kalina M. 5 ; Puxbaum H. 5 ;Nickus U. 6 ; Ulrich E. 7 ; Probst A. 8 1 CNR Institute of Ecosystem Study, Verbania Pallanza, Italy 2 Cantonal Agency for Water Protection and Treatment, Bellinzona, Canton Ticino, Switzerland; 3 CNR Water Research Institute, Department of Hydrobiology Applied to Water Pollution, Brugherio, Milan, Italy; 4 WSL, Swiss Federal Institute for Forest, Snow and Landscape Research, Birmensdorf, Switzerland; 5 Institute of Analytical Chemistry IAC , Vienna University of Technology, Vienna, Austria; 6 Institute of Meteorology and Geophysics, University of Innsbruck, Innsbruck, Austria; 7 Office National des Forets, Fontainebleau, France; 8 Laboratoire des Mecanismes et Transferts en Geologie LMTG , UMR 5563 CNRS/IRD/UPS, Toulouse, France Several research programs monitoring atmospheric deposition have been launched in the Alpine countries in the last few decades. This paper uses data from previous and ongoing projects to i investigate geographical variability in wet deposition chemistry over the Alps; ii assess temporal trends of the major chemical variables in response to changes in the atmospheric emission of pollutants; iii discuss the potential relationship between the status of atmospheric deposition and its effects on forest ecosystems in the alpine and subalpine area, focusing particularly on nitrogen input. We also present results of studies performed at a local level on specific topics such as long term changes in lead deposition and the role of occult deposition in total nitrogen input. The analysis performed here highlights the marked geographical variability of atmospheric deposition in the Alpine region. Apart from some evidence of geographically limited effects, due to local sources, no obvious gradients were identified in the major ion deposition. The highest ionic loads were recorded in areas in the foothills of the Alps, such as the pre alpine area in North Western Italy and the area of Canton Ticino, Switzerland. Trend analysis shows a widespread decrease in the acidity of precipitation in the last 15 20 years as a consequence of the reduced emission of S compounds. On the other hand, nitrate concentrations in rain have not changed so much, and ammonium has decreased significantly only at the Austrian sampling sites. The deposition of N is still well above the estimated critical loads of nutrient N at some forest sites in the alpine and subalpine areas, thus confirming the critical situation of both terrestrial and aquatic ecosystems regarding N inputs. Existing data highlights the importance of continuously monitoring atmospheric deposition chemistry in the Alpine area, taking account of acidifying elements, nutrients and other pollutants such as heavy metals and organic compounds. There is also a need for unifying sampling and analytical methods in order to obtain comparable data from the different regions of the Alps. 562 Articolo pubblicato 5_Hydrobiologia_2006.pdf Articolo in rivista Kluwer Academic Publishers 0018 8158 Hydrobiologia The Hague. Print Hydrobiologia The Hague. Print Hydrobiologia The Hague. Print Hydrobiologia. The Hague. Print Hydrobiologia Dordrecht The Hague. Print Hydrobiologia Boston The Hague. Print Hydrobiologia London The Hague. Print mariacristina.brizzio BRIZZIO MARIA CRISTINA ARISCI SILVIA michela.rogora ROGORA MICHELA rosario.mosello MOSELLO ROSARIO TA.P02.014.002 Impatto dei cambiamenti globali sugli ecosistemi acquatici |
