Contribution of deeper soil horizons to N and C cycling during the snow-free season in alpine tundra, NW Italy

Abstract

(AAM) is copyrighted and published by Elsevier. It is posted here by agreement between Elsevier and the University of Turin. Changes resulting from the publishing process-such as editing, corrections, structural formatting, and other quality control mechanisms-may not be reflected in this version of the text. The definitive version of the text was subsequently published in CATENA, 155, 2017, 10.1016/j.catena.2017.03.007. You may download, copy and otherwise use the AAM for non-commercial purposes provided that your license is limited by the following restrictions: (1) You may use this AAM for non-commercial purposes only under the terms of the CC-BY-NC-ND license. (2) The integrity of the work and identification of the author, copyright owner, and publisher must be preserved in any copy.

Abiotic Parameters and Pedogenesis as Controlling Factors for Soil C and N Cycling Along an Elevational Gradient in a Subalpine Larch Forest (NW Italy)

“…In order to obtain possible responses to the expected warming on soil carbon and nitrogen cycling, biogeochemical properties might be analyzed and used as short-term indicators due to their great sensitivity, even to slight environmental modifications [5], such as changes in pedoclimatic factors. Soil moisture and temperature are in fact known to be of paramount importance, affecting microorganisms and nutrient cycling in forests soil [6] and in higher alpine tundra soils [7]. In mountain forest ecosystems, the pedoclimatic factors are known to be heavily influenced by the seasonal snow cover, which can vary in its depth and duration each year.…”

“…Less snow cover means less soil thermal insulation during winter [22], and according to soil frost intensity and the number of freeze/thaw cycles, it could: (a) increase fine roots mortality [23,24]; (b) alter the soil structure due to the disruption of the aggregates [25,26]; (c) influence the microbial activity with large consequences on CO 2 fluxes [27][28][29][30]. High concentrations of soil C and N forms are usually found when freeze/thaw cycles occur or when soil is affected by severe freezing [7,31]. The thermal stresses observed during winter could influence the soil and also the soil solution chemistry in the subsequent snow-free season [32].…”

“…The thermal stresses observed during winter could influence the soil and also the soil solution chemistry in the subsequent snow-free season [32]. Magnani et al [7], in the alpine tundra soils of the northwest (NW) Alps, found higher soil microbial nitrogen concentrations during years characterized by an elevated number of soil freeze/thaw cycles. They also found that in years with greater snow cover duration, the microbial biomass in the subsequent growing season was lower, as a potential consequence of the greater consumption of soil resources under the long lasting snowpack.…”

“…Similar results were also obtained by Viglietti et al [32] in a subalpine forest ecosystem with a significant increase in nitrate concentration in soil solution during spring and summer after a year characterized by late snow accumulation (snow manipulation experiment). Consequently, the snow depth and duration may have implications for the subsequent summer processes, such as the vegetation growth [33,34] and the ground thermal regime [7,35].…”

On characteristics and dynamics of water-rock glacier interactions in mountain areas (Western Italian Alps)

“…Generally, EC and solute content in the Col d'Olen Rock Glacier Pond were comparable to values measured in rock-glacier outflows in catchments composed of metamorphic rocks (Krainer andMostler, 2001a,b, 2002;Berger et al, 2004;Krainer et al, 2007), but lower than values measured in other rock glacier outflows (Williams et al, 2006;Thies et al, 2013) and lakes (Thies et al, 2007;Ilyashuk et al, 2014). NO 3 concentrations in the pond, except during high rock-glacier discharge periods at RG3, were comparable to those measured in a rock-glacier lake in the Central Eastern European Alps (Ilyashuk et al, 2014) and other high elevations surface waters (Balestrini et al, 2014;Magnani et al, 2017), but lower than those measured in rock-glacier outflows in the Colorado Front Range (Williams et al, 2007). Trace-element concentrations in this study were lower than ones measured in other rock-glacier outflows (Thies et al, 2013) and rock-glacier lakes (Ilyashuk et al, 2014).…”