“…Indeed, the areas surrounding the Alpine rim produce nitrogen deposition among the highest in Europe (Rogora et al, 2001) and, in 2009, the total N concentration (0.88 mg L -1 ) and deposition rates (14.4 kg N ha -1 y -1 , calculated by annual precipitation and average N content) at the sampling station of La Thuile were high and similar to those usually reported for the Alpine range (N deposition rate: 14-15 kg N ha -1 y -1 ; Rogora et al, 2006). However, the final nitrogen concentration in the lakes depends on retention process (closely related to vegetation and catchment characteristics) (Marchetto et al, 1995;Rzychon and Worsztynowicz, 2008), in addition to N deposition rate. Inorganic nitrogen concentration in the lakes studied (0.07 mg N L -1 in NIV, and 0.04 mg N L -1 in TRS) was considerably lower than the values found in other lakes in the Gran Paradiso National Park (0.17 mg L -1 , average IN concentration from a set of 15 Alpine lakes sampled in 2009, unpublished data) and for the Alps (0.8-1.0 mg L -1 ) (Rogora et al, 2003(Rogora et al, , 2008, and it was comparable with the values from European and non-European pristine areas subject to low atmospheric input of N compounds (Boavida and Gliwicz, 1996;Tartari et al, 1998;Murphy et al, 2010).…”