Long-term patterns of deposition, soil solution and stream water chemistry in an Alpine forest ecosystem.

Alpine ecosystems, both terrestrial and aquatic, are particularly sensitive to climate change and alteration of biogeochemical cycles. With the aim of understanding the potential effects due to the combination of climate change and atmospheric deposition, we evaluated the temporal evolution of some climatic factors and the chemical composition of atmospheric deposition, surface water and soil solution in an alpine LTER station. Monitoring data from for deposition (1995-2013), stream water (1997-2013), and soil solution (2006-2013) chemistries were statistically analyzed for long-term trends and seasonal patterns by using Seasonal Kendall test (SKT). Similarly to several European and North America sites we observed a sharp decline in sulfur concentrations, and a subsequent increase of pH values in all the analyzed environmental matrices. A less pronounced reducing has been detected for nitrate, but not for ammonia. These results are examined considering the seasonal variations of temperatures (min, max and mean), the amount of rain and snow, and the hydrological regime