| Abstract | In alpine tundra the interannual and seasonal variability of C and N forms in soil and lake water during the short snow-free season could be significant and related to climatic and pedoclimatic variables. The hypothesis that not only the climatic and pedoclimatic parameters recorded during the summer season but also the ones measured during the previous snow-covered season could contribute to explaining the C and N dynamics in soil and surface water was tested along 10 snow-free seasons in 3 sites in the alpine tundra in the north-western Italian Alps (LTER site Istituto Mosso). Among the considered parameters, the snow cover duration (SCD) exerted a primary control on soil N-NH , DOC, C , N and DOC:DON ratio, with an inverse relationship. A long SCD might cause the consumption of all the subnival substrata by the soil microorganisms, determining a C starvation during the subsequent snow-free season. An opposite trend was observed for the lake water, where a longer SCD corresponded to a higher content of inorganic N forms. Among the pedoclimatic indices, the number of soil freeze/thaw cycles (FTC) recorded during the snow-covered season had a positive relation with most of soil C and N forms and N-NO in lake water. Only the soil DON showed an inverse pattern, and this result is consistent with the hypothesis that FTC released soil DON, subsequently decomposed and mineralized. Only N-NO had a significant intraseasonal variability, reaching the highest values in September both in soil and water, revealing a significant slowdown of the contribution of soil N immobilization processes. |
| Text | 406800 2019 10.3897/natureconservation.34.30737 Scopus 2 s2.0 85065587761 ISI Web of Science WOS 000466756300004 LTER snow cover duration soil temperature freeze/thaw cycles leaching N NO3 Climatic and pedoclimatic factors driving C and N dynamics in soil and surface water in the alpine tundra NW Italian Alps Freppaz M.; Viglietti D.; Balestrini R.; Lonati M.; Colombo N. Department of Agricultural, Forest and Food Sciences, University of Torino, Largo Paolo Braccini 2, Grugliasco TO , 10095, Department of Agricultural, Forest and Food Sciences, University of Torino, Largo Paolo Braccini 2, 10095, Grugliasco TO , Italy, , Italy; Research Center on Natural Risk in Mountain and Hilly Environments, NatRisk, University of Torino, Largo Paolo Braccini 2, Grugliasco TO , 10095, Research Center on Natural Risk in Mountain and Hilly Environments, NatRisk, University of Torino, Largo Paolo Braccini 2, 10095, Grugliasco TO , Italy, , Italy; Water Research Institute IRSA CNR , Via del Mulino 19, Brugherio MB , 20861, Water Research Institute IRSA CNR , Via del Mulino 19, 20861, Brugherio MB , Italy, , Italy In alpine tundra the interannual and seasonal variability of C and N forms in soil and lake water during the short snow free season could be significant and related to climatic and pedoclimatic variables. The hypothesis that not only the climatic and pedoclimatic parameters recorded during the summer season but also the ones measured during the previous snow covered season could contribute to explaining the C and N dynamics in soil and surface water was tested along 10 snow free seasons in 3 sites in the alpine tundra in the north western Italian Alps LTER site Istituto Mosso . Among the considered parameters, the snow cover duration SCD exerted a primary control on soil N NH , DOC, C , N and DOC DON ratio, with an inverse relationship. A long SCD might cause the consumption of all the subnival substrata by the soil microorganisms, determining a C starvation during the subsequent snow free season. An opposite trend was observed for the lake water, where a longer SCD corresponded to a higher content of inorganic N forms. Among the pedoclimatic indices, the number of soil freeze/thaw cycles FTC recorded during the snow covered season had a positive relation with most of soil C and N forms and N NO in lake water. Only the soil DON showed an inverse pattern, and this result is consistent with the hypothesis that FTC released soil DON, subsequently decomposed and mineralized. Only N NO had a significant intraseasonal variability, reaching the highest values in September both in soil and water, revealing a significant slowdown of the contribution of soil N immobilization processes. 34 Published version http //www.scopus.com/record/display.url eid=2 s2.0 85065587761 origin=inward Climatic and pedoclimatic factors driving C and N dynamics in soil and surface water in the alpine tundra NW Italian Alps NC_Freppaz.pdf Articolo in rivista Pensoft Publishers, 1314 3301 Nature Conservation Sofia. Online Nature Conservation Sofia. Online Nat. Conserv. Sofia. Online Nature Conservation. Sofia. Online raffaella.balestrini BALESTRINI RAFFAELLA |
