Swiss Federal Institute for Forest, Snow and Landscape Research

About: Swiss Federal Institute for Forest, Snow and Landscape Research is a facility organization based out in Birmensdorf, Switzerland. It is known for research contribution in the topics: Climate change & Soil water. The organization has 1256 authors who have published 3222 publications receiving 161639 citations. The organization is also known as: WSL.

Effects of root exudates and humic substances on weathering kinetics

Abstract: The effect of complex natural organic ligands on the weathering kinetics of aluminum oxide was investigated in laboratory experiments. A peat-derived humic substance and root exudates obtained from ectomycorrhizal (Picea abies — Hebeloma crustuliniforme) and non-mycorrhizal Norway Spruce trees; and γ-Al2O3 were used as a model system. The experimental weathering rates are in accordance with a surface-controlled dissolution mechanism. The effect of the humic material on dissolution rates appears to depend on the degree of protonation of the humic (macro)molecules: we observed dissolution-enhancement or -inhibition at pH 3 and 4, respectively. Ectomycorrhizal exudates proved to be effective weathering agents at pH 4, as opposed to humic material and non-mycorrhizal exudates. Our results suggest that (i) the role of humic materials in mineral weathering and podzolization is different from what is commonly thought, and (ii) mineral weathering rates in the rhizosphere may be higher than in the bulk soil.

Application of ash (Fraxinus excelsior L.) roots to determine erosion rates in mountain torrents

Abstract: Due to the effect of global change, the potential risk of natural hazards occurring in alpine areas is expected to increase to an even higher risk-level than has been recorded during the last century. These global changes potentially also have distinct influences on fluvial processes in torrents causing erosion on slopes and riverbanks in forested areas. Dating the time of root exposure along riverbanks combined with common dendrogeomorphic analysis applied to tree trunks helps to reconstruct the erosion dynamics leading to a potential destabilization of adjoining trees. The advantage of using exposed roots compared to common erosion measurement techniques is that the erosion rates can be quantified with annual resolution. The first year of exposure can be determined precisely by the characterization of the wood anatomical changes in the microscopic structure of the root. This study is the first to concentrate on the analysis of wood anatomical features of exposed roots of angiosperm trees aiming to reconstruct erosional processes. Two mountain torrents were selected as study sites based on a preliminary evaluation of various Swiss alpine areas. Sites of special interest concerning erosive processes were classified and examined in five different geomorphological groups representing different processes. The analysis comprised the examination of the exposed tree roots in each group. The project shows the potential of roots in general and in particular roots of deciduous angiosperm trees for geomorphological research, especially concerning erosion studies.

Greenland surface air temperature changes from 1981 to 2019 and implications for ice-sheet melt and mass-balance change

Abstract: We provide an updated analysis of instrumental Greenland monthly temperature data to 2019, focusing mainly on coastal stations but also analysing ice-sheet records from Swiss Camp and Summit. Significant summer (winter) coastal warming of ~1.7 (4.4) C occurred from 1991-2019, but since 2001 overall temperature trends are generally flat and insignificant due to a cooling pattern over the last 6-7 years. Inland and coastal stations show broadly similar temperature trends for summer. Greenland temperature changes are more strongly correlated with Greenland Blocking than with North Atlantic Oscillation changes. In quantifying the association between Greenland coastal temperatures and Greenland Ice Sheet (GrIS) mass-balance changes, we show a stronger link of temperatures with total mass balance rather than surface mass balance. Based on Greenland coastal temperatures and modelled mass balance for the 1972-2018 period, each 1C of summer warming corresponds to ~ (91) 116 Gt yr-1 of GrIS (surface) mass loss and a 26 Gt yr-1 increase in solid ice discharge. Given an estimated 4.0-6.6C of further Greenland summer warming according to the regional model MAR projections run under CMIP6 future climate projections (SSP5-8.5 scenario), and assuming that ice-dynamical losses and ice sheet topography stay similar to the recent past, linear extrapolation gives a corresponding GrIS global sea-level rise (SLR) contribution of ~10.0-12.6 cm by 2100, compared with the 8-27 cm (mean 15 cm) “likely” model projection range reported by IPCC (2019, SPM.B1.2). However, our estimate represents a lower limit for future GrIS change since fixed dynamical mass losses and amplified melt arising from both melt-albedo and melt-elevation positive feedbacks are not taken into account here.