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Hidden soils and their carbon stocks at high-elevation in the European Alps (North-West Italy)

2020; Elsevier BV; Volume: 198; Linguagem: Inglês

10.1016/j.catena.2020.105044

1872-6887

Emanuele Pintaldi, Michele D’Amico, Nicola Colombo, Chiara Colombero, Luigi Sambuelli, Claudio De Regibus, Diego Franco, Luigi Perotti, Luca Paro, Michele Freppaz,

Cryospheric studies and observations

Alpine soils store large quantities of total organic carbon (TOC). Given their high sensitivity to climate change, they may release large amounts of CO2 in a warming climate scenario. Thus, it is important to know their C stocks in order to estimate its possible release. While C stocks of forest, dwarf shrub and alpine grassland soils are well documented, little is known about soils and C stocks in high-elevated periglacial environments dominated by frost-driven processes. The object of this study is the periglacial environment of the Stolenberg Plateau (LTER site Istituto Mosso, 3030 m a.s.l.), at the foot of the Monte Rosa Massif (NW Italian Alps). The plateau is mostly covered by a thick stony layer, organized in periglacial blockfields and blockstreams. The plant cover reaches only 3–5%. During the construction of a chair lift, open trenches revealed, unexpectedly, well-developed soils under the active periglacial stone cover. In particular, thick (30–65 cm) and dark TOC-rich A horizons were observed. Below these Umbric horizons, Cambic Bw ones were developed but discontinuous. Despite the lack of vegetation, C stocks were remarkably high (up to ~ 5 kg m−2), comparable to vegetated soils at lower elevation. Non-invasive geophysical methods revealed that these hidden soils were widespread on the plateau under the stony cover, with a mean thickness of around 50 cm. These TOC-rich soils, without vegetation and covered by periglacial landforms, represent a unique pedoenvironment suggesting new perspectives on the actual C-stocks at high-elevation sites, which are probably underestimated.