Brighenti et al. (2025) Cryosphere and lithology influence the hydrological gradients of high elevation Alpine catchments

Identification

• Journal: CATENA
• Year: 2025
• Date: 2025-12-04
• Authors: Stefano Brighenti, Matteo Delpero, Francesca Bearzot, Giulia Bertolotti, Monica Tolotti, Maria Cristina Bruno, Andrea Fischer, Gerfried Winkler, Giulio Voto, Agnese Aguzzoni, Werner Tirler, Francesco Comiti
• DOI: 10.1016/j.catena.2025.109676

Research Groups

• Eco Research, Bolzano, Italy
• Competence Centre for Mountain Innovation Ecosystems, Free University of Bozen/Bolzano, Bolzano, Italy
• Faculty of Agricultural, Environmental and Food Sciences, Free University of Bozen/Bolzano, Bolzano, Italy
• Faculty of Earth, Energy, and Environment, University of Calgary, Calgary, Canada
• Institute for Interdisciplinary Mountain Research, Austrian Academy of Sciences, Innsbruck, Austria
• Department of Earth Sciences, NAWI Graz Geocenter, University of Graz, Graz, Austria
• Research and Innovation Centre, Fondazione Edmund Mach, S. Michele all’Adige, Italy
• National Biodiversity Future Center (NBFC), Universit`a di Palermo, Palermo, Italy
• Department of Land, Environment, Agriculture, and Forestry, University of Padova, Padova, Italy

Short Summary

This study investigates how receding cryosphere and lithology influence the hydrological, thermal, and chemical gradients in two high-elevation Alpine catchments. It finds that rock glaciers are major hydrological regulators, contributing significantly to runoff and buffering water temperature, while predisposing lithology in glacierized catchments can lead to geochemical hotspots with elevated trace element concentrations.

Objective

• To estimate the spatial behaviour of water temperature, stable water isotopes, and water chemistry along the river continuum in high-elevation Alpine catchments.
• To determine if meltwater-derived runoff from snow and ice is larger than rainwater contribution in glacierized versus non-glacierized catchments.
• To assess if the hydrological contribution from different landforms (glaciers, rock glaciers, moraines) differs between catchment types.
• To investigate if tributary springs from cold rocky landforms (CRLs) decrease water temperature and increase solute concentrations along the main streams.

Study Configuration

• Spatial Scale: Two headwater catchments in the Eastern Italian Alps (Upper Etsch/Adige River basin, South Tyrol):
  • Madritsch/Madriccio creek catchment (non-glacierized): 7.6 km², elevation range ~2400–3400 m a.s.l.
  • Rosshütte/Capanna del Cavallo (Lazaun) Creek catchment (glacierized): 3.8 km², elevation range ~2400–3400 m a.s.l.
• Temporal Scale: Summer 2022 (20 June – 27 September) and 2023 (14 June – 12 October), with monthly field campaigns.

Methodology and Data

• Models used:
  • End-member mixing models (hydrological and spatial frameworks) using the R package MixSiar v 3.1.12.
  • Principal Component Analysis (PCA) using SPSS software (IBM, 2018) for thermal indices and trace element concentrations.
• Data sources:
  • Field measurements: Water temperature (data loggers and portable probe, accuracy 0.1 °C to 0.53 °C), electrical conductivity (EC) (portable probe, accuracy 0.1 µS cm⁻¹), pH (automatic titrator).
  • Laboratory analyses of water samples:
    • Stable isotopes (δ²H, δ¹⁸O) using cavity ring-down laser spectroscope (CRDS Picarro L2130i, precision: 0.1 ‰ for δ²H, 0.025 ‰ for δ¹⁸O).
    • Concentrations of 32 trace elements (e.g., Li, Al, Ni, Mn, Zn, Y) by Inductively Coupled Plasma Mass Spectrometry (ICP-MS ICAP-Q).
    • Concentrations of major ions (HCO₃⁻, Ca²⁺, Mg²⁺, Cl⁻, Na⁺, K⁺, SO₄²⁻) by ion chromatography.
  • Reference isotopic data for rainwater, snowmelt, and glacier ice melt from Delpero et al. (2025).
  • Rock glacier inventory and classification from Autonomous Province of Bozen/Bolzano APB (2025).
  • Permafrost likelihood map (Boeckli et al., 2012).

Main Results

• Hydrological Contributions: Meltwater was the dominant runoff component in both catchments, but significantly higher in the glacierized Lazaun (>90% at outlet) than in the non-glacierized Madritsch (70–80% at outlet). Rainwater contributed 20–30% in Madritsch and <10% in Lazaun. Rock glaciers contributed 60–65% to stream runoff at both catchment outlets, with till and moraine springs accounting for >30%.
• Thermal Gradients: In the non-glacierized Madritsch, water temperature increased from 1.6 °C at the intact rock glacier spring to 7.3 ± 1.5 °C at the catchment outlet. In the glacierized Lazaun, proglacial reaches had water temperatures of 6.9 ± 2.6 °C, but cold rock glacier springs decreased water temperatures by 2–4 °C downstream, leading to the lowest daily and seasonal fluctuations in these sections. Intact rock glacier springs were consistently the coldest (<2.0 °C).
• Water Chemistry: Stream and spring waters were dominated by sulphate, calcium, and magnesium. The glacierized Lazaun catchment, a geochemical hotspot, showed significantly higher SO₄²⁻ over HCO₃⁻ (S-ratio) and elevated concentrations of trace elements (e.g., Ni, Al, Mn, Zn, Y, Li) due to sulphide oxidation from predisposing paragneiss and micaschist lithology. In contrast, the non-glacierized Madritsch catchment exhibited lower S-ratios and higher buffering from carbonate and silicate dissolution (quartz-rich phyllites and serpentinites), resulting in lower heavy metal concentrations.

Contributions

• Provides a quantitative assessment of the shifting hydrological, thermal, and chemical gradients in Alpine catchments undergoing deglaciation.
• Highlights the increasing role of rock glaciers as significant hydrological regulators, contributing substantially to stream runoff and providing thermal buffering in warming mountain environments.
• Demonstrates the critical combined influence of cryospheric processes (glacier retreat, permafrost degradation) and local lithology in driving water chemistry, identifying specific geochemical hotspots with elevated trace element concentrations.
• Offers crucial insights for understanding hydrochemical shifts and informing sustainable water management strategies in rapidly changing mountain ecosystems globally.

Funding

• Project Rock-me (Chemical response of Alpine ROCK glaciers to global warming: hydroecological consequences of trace eleMent Export) funded by the GECT Euregio Science Fund - 4th call (IPN-159).
• Consortium iNEST (Interconnected North-East Innovation Ecosystem) funded by the European Union Next-Generation EU (PNRR) Missione 4 Componente 2, Investimento 1.5 D.D. 1058 23/06/2022, ECS_00000043 (supported S. Brighenti).
• Department of Innovation, Research, University and Museums of the Autonomous Province of Bozen/Bolzano (covered Open Access publication costs).

Citation

@article{Brighenti2025Cryosphere,
  author = {Brighenti, Stefano and Delpero, Matteo and Bearzot, Francesca and Bertolotti, Giulia and Tolotti, Monica and Bruno, Maria Cristina and Fischer, Andrea and Winkler, Gerfried and Voto, Giulio and Aguzzoni, Agnese and Tirler, Werner and Comiti, Francesco},
  title = {Cryosphere and lithology influence the hydrological gradients of high elevation Alpine catchments},
  journal = {CATENA},
  year = {2025},
  doi = {10.1016/j.catena.2025.109676},
  url = {https://doi.org/10.1016/j.catena.2025.109676}
}