| Abstract | High-resolution temporal measurements in remote, high-elevation surface waters are required to better understand
the dynamics of nitrate (NO3? ) in response to changes in meteoclimatic conditions. This study reports on the
first use of a UV-Vis submersible spectrophotometric probe (UV-Vis probe) to measure the hourly concentration
of nitrate nitrogen (NO3? -N) in a pond located at 2722 m a.s.l. in an alpine tundra area (NW Italian Alps), during
two snow-free seasons (July-October) in 2014 and 2015. Weekly analyses of NO3? -N and stable isotopes of water
(?18O and ?2H), together with continuous meteorological, water temperature, and turbidity measurements, were
performed over the same period. The integration of in-situ UV-Vis spectrophotometric measurements with
weekly samples allowed depicting the role of summer precipitation, snow melt, and temperature (air and water)
in influencing NO3? dynamics. Short-duration meteorological events (e.g., summer storms and rain-on-snow
events) produced rapid variations of in-pond NO3? concentration, i.e., fivefold increase in 18 h, that would not
be detectable using the traditional manual collection of discrete samples. The observed seasonal variability of
NO3? concentration, negatively correlated with water temperature, highlighted the important role of in-pond
biological processes leading to an enhanced N uptake and to the lowest NO3? concentration in the warmer periods.
The occurrence of heavy rainfall events critically altered the expected seasonal NO3? trends, increasing the
N supply to the pond. The comparison of N dynamics in two years characterised by extremely different
meteoclimatic conditions allowed us to obtain insights on the potential effects of climate changes (e.g., high air
temperature, heavy rainfalls, and rain-on-snow events) on sensitive aquatic ecosystems as high-elevation ponds. |
| Authors | N. Colombo a,b,c, R. Balestrini d, D. Godone e,c,*, D. Vione f,c, D. Said-Pullicino a, G. Viviano d, M. Martin a, C.A. Delconte d, S. Fratianni g,c, A.G. Capodaglio h, E. Pintaldi a, M. Freppaz a,c, F. Salerno d, |
| Text | 488967 2024 10.1016/j.catena.2023.107635 NO3 surface waters mountains LTER turbidity Nitrogen retention High resolution temporal variations of nitrate in a high elevation pond in alpine tundra NW Italian Alps N. Colombo a,b,c, R. Balestrini d, D. Godone e,c, , D. Vione f,c, D. Said Pullicino a, G. Viviano d, M. Martin a, C.A. Delconte d, S. Fratianni g,c, A.G. Capodaglio h, E. Pintaldi a, M. Freppaz a,c, F. Salerno d, a University of Turin, Department of Agricultural, Forest and Food Sciences, Grugliasco, Italy b CNR IRSA National Research Council Water Research Institute , Rome, Italy c Research Center on Natural Risk in Mountain and Hilly Environments, NatRisk, University of Turin, Grugliasco, Italy d CNR IRSA National Research Council Water Research Institute , Brugherio, Italy e CNR IRPI National Research Council Research Institute for Geo Hydrological Protection , Turin, Italy f University of Turin, Department of Chemistry, Turin, Italy g University of Turin, Department of Earth Sciences, Turin, Italy h University of Pavia, Department of Civil Engineering and Architecture, Pavia, Italy i CNR ISP National Research Council Institute of Polar Sciences , Venezia Mestre, VE, Italy High resolution temporal measurements in remote, high elevation surface waters are required to better understand the dynamics of nitrate NO3 in response to changes in meteoclimatic conditions. This study reports on the first use of a UV Vis submersible spectrophotometric probe UV Vis probe to measure the hourly concentration of nitrate nitrogen NO3 N in a pond located at 2722 m a.s.l. in an alpine tundra area NW Italian Alps , during two snow free seasons July October in 2014 and 2015. Weekly analyses of NO3 N and stable isotopes of water 18O and 2H , together with continuous meteorological, water temperature, and turbidity measurements, were performed over the same period. The integration of in situ UV Vis spectrophotometric measurements with weekly samples allowed depicting the role of summer precipitation, snow melt, and temperature air and water in influencing NO3 dynamics. Short duration meteorological events e.g., summer storms and rain on snow events produced rapid variations of in pond NO3 concentration, i.e., fivefold increase in 18 h, that would not be detectable using the traditional manual collection of discrete samples. The observed seasonal variability of NO3 concentration, negatively correlated with water temperature, highlighted the important role of in pond biological processes leading to an enhanced N uptake and to the lowest NO3 concentration in the warmer periods. The occurrence of heavy rainfall events critically altered the expected seasonal NO3 trends, increasing the N supply to the pond. The comparison of N dynamics in two years characterised by extremely different meteoclimatic conditions allowed us to obtain insights on the potential effects of climate changes e.g., high air temperature, heavy rainfalls, and rain on snow events on sensitive aquatic ecosystems as high elevation ponds. 235 Published version https //www.sciencedirect.com/science/article/pii/S0341816223007269 via%3Dihub High resolution temporal variations of nitrate in a high elevation pond in alpine tundra NW Italian Alps Catena2023.pdf Articolo in rivista Catenian Association 0008 7769 Catena London Catena London Catena London Journal of the Catenian Association London raffaella.balestrini BALESTRINI RAFFAELLA franco.salerno SALERNO FRANCO carloandrea.delconte DELCONTE CARLO ANDREA danilofrancescostefano.godone GODONE DANILO FRANCESCO STEFANO TA.P05.010.001 Tecniche e tecnologie per il monitoraggio dei parametri che caratterizzano le evoluzioni morfologiche di alvei e versanti instabili. DTA.AD003.141.001 Sviluppo sistemi monitoraggio innovativi |
