Adrian Gilli

Last Name

Gilli

First Name

Adrian

ORCID

0000-0003-4193-2157

Organisational unit

01659 - Lehre Erd- und Planetenwissenschaften

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Publications 1 - 10 of 69

Frequent floods in the European Alps coincide with cooler periods of the past 2500 years
Glur, Lukas; Wirth, Stefanie B.; Büntgen, Ulf; et al. (2013)
Scientific Reports
Severe floods triggered by intense precipitation are among the most destructive natural hazards in Alpine environments, frequently causing large financial and societal damage. Potential enhanced flood occurrence due to global climate change would thus increase threat to settlements, infrastructure, and human lives in the affected regions. Yet, projections of intense precipitation exhibit major uncertainties and robust reconstructions of Alpine floods are limited to the instrumental and historical period. Here we present a 2500-year long flood reconstruction for the European Alps, based on dated sedimentary flood deposits from ten lakes in Switzerland. We show that periods with high flood frequency coincide with cool summer temperatures. This wet-cold synchronism suggests enhanced flood occurrence to be triggered by latitudinal shifts of Atlantic and Mediterranean storm tracks. This paleoclimatic perspective reveals natural analogues for varying climate conditions, and thus can contribute to a better understanding and improved projections of weather extremes under climate change.
Holocene seismic activity in south-eastern Switzerland: Evidence from the sedimentary record of Lake Silvaplana
Bellwald, Benjamin; Nigg, Valentin; Fabbri, Stefano C.; et al. (2024)
Sedimentology
High-Alpine regions are prone to a large variety of geohazards, among which earthquakes have the strongest impact on landscape and local population. Historic records indicate a moderate to high seismic activity in the northern, south-western and central parts of Switzerland. In contrast, south-eastern Switzerland has less historic earthquake chronicles due to the low population density, resulting in a poorly constrained seismic event catalogue. The aim of this study is to evaluate the palaeoseismic activity for south-eastern Switzerland by using the sedimentary record of Lake Silvaplana in the Engadine Valley. A dense grid of high-resolution two-dimensional seismic profiles, high-resolution bathymetry and a 10 m long sediment core from the deepest basin were used to investigate the stratigraphy of the lake sediments. The bathymetry reveals a flat basin, flanked by steep slopes to the north-west and south-east. The acoustic basement consists of four ridges, and gently-dipping fans to the south-west and north-east. Expressions of slope failure can be identified in all domains of the lake floor and the subsurface data. Multiple coevally-triggered chaotic mass-flow deposits, overlain by megaturbidites with a coarse-sand base, have been detected along ten horizons in the seismic data. The four most recent of these deposits are cored and radiocarbon dated to approximately 230, 310, 960 and 1330 cal yr bp, indicating four over-regional seismic events that triggered large slope failures in Lake Silvaplana in the last 1400 years. Correlation with sediments of Lake Sils, Lake Como, Lake Iseo and Lake Ledro indicate within radiocarbon uncertainties a large earthquake around 1330 cal yr bp. Within their age ranges, the postulated earthquake at 310 cal yr bp (1640 ce) further correlates with a moment magnitude Mw ca 5.4 event in Ftan in 1622 ce, and the 960 cal yr bp (990 ce) earthquake correlates with a Mw ca 5.2 earthquake in Brescia in 1065 ce. Six mass-movement deposits, also suggested to be caused by earthquakes, were not reached by the sediment core and have suggested ages between 7800 and 11 300 cal yr bp. Thus, Lake Silvaplana sediments provide the first reliable record of seismic activity for the mid and Late Holocene in this region, likely related to the neotectonic activity of the Engadine Line, a major fault zone running along the main valley.
Lake sediments tell the story of climate change
Naeher, Sebastian; North, Ryan P.; Gilli, Adrian; et al. (2014)
Chimia
Corrigendum to: “Variations of sedimentary Fe and Mn fractions under changing lake mixing regimes, oxygenation and land surface processes during Late-glacial and Holocene times” [Sci. Total Environ. 755 (2021) 143418]
Makri, Stamatina; Wienhues, Giulia; Bigalke, Moritz; et al. (2023)
Science of The Total Environment
Branched GDGT-based temperature calibrations from Central European lakes
Bauersachs, Thorsten; Schubert, Carsten J.; Mayr, Christoph; et al. (2024)
Science of The Total Environment
Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are common in lake sediments, where they are frequently employed to infer mean annual air temperatures (MAAT) or air temperatures of months above freezing (MAF) using the MBT'5Me lipid paleothermometer. The reliable reconstruction of such temperatures, however, requires robust calibration functions. Here, we investigated brGDGT distributions in surface sediments from 41 freshwater lakes located along an altitudinal gradient across the Alps (Central Europe) and spanning a MAAT range from 1.3 to 12.9 °C. Linear regression analysis demonstrates that fractional abundances of brGDGTs are strongly correlated with MAAT and MAF allowing to establish regional MBT'5Me-based transfer functions: MAAT (°C) = −2.19 + 31.91 × MBT'5Me (r2 = 0.72; RMSE = 1.51 °C) and MAF (°C) = 4.81 + 15.64 × MBT'5Me (r2 = 0.64, RMSE = 0.92 °C). Stepwise forward selection yielded the following, alternate temperature calibrations: MAAT (°C) = 7.11 + 67.66 × Ib – 13.54 × IIIa (r2 = 0.72; RMSE = 1.47 °C) and MAF (°C) = 5.19 + 16.22 × Ia (r2 = 0.66; RMSE = 0.98 °C). Our results demonstrate that the above calibration functions allow precise temperature reconstructions using lacustrine sediment records. However, our data also show that high-altitude lakes are more prone to warm bias and that lakes characterized by comparatively high abundances of 6-methyl brGDGTs show aberrant behaviors with temperature offsets up to ∼7 °C. Determining the IR6Me, as an independent control complementary to the MBT'5Me, is thus essential to validate the robustness of brGDGT-based temperature reconstructions of past climates. A cut-off value of 0.50 for the IR6Me is here proposed, after which MBT'5Me-reconstructed MAATs from lacustrine archives should be regarded as unreliable.
Late Pleistocene environmental change in eastern Patagonia and Tierra del Fuego
Ariztegui, Daniel; Anselmetti, Flavio S.; Gilli, Adrian; et al. (2008)
Developments in Quaternary Science ~ The late Cenozoic of Patagonia and Tierra del Fuego
A 2000 year long seasonal record of floods in the southern European Alps
Wirth, Stefanie B.; Gilli, Adrian; Simonneau, Anaëlle; et al. (2013)
Geophysical Research Letters
Knowledge of past natural flood variability and controlling climate factors is of high value since it can be useful to refine projections of the future flood behavior under climate warming. In this context, we present a seasonally resolved 2000 year long flood frequency and intensity reconstruction from the southern Alpine slope (North Italy) using annually laminated (varved) lake sediments. Floods occurred predominantly during summer and autumn, whereas winter and spring events were rare. The all-season flood frequency and, particularly, the occurrence of summer events increased during solar minima, suggesting solar-induced circulation changes resembling negative conditions of the North Atlantic Oscillation as controlling atmospheric mechanism. Furthermore, the most extreme autumn events occurred during a period of warm Mediterranean sea surface temperature. Interpreting these results in regard to present climate change, our data set proposes for a warming scenario, a decrease in summer floods, but an increase in the intensity of autumn floods at the South-Alpine slope.
Mid-Holocene strengthening of the Southern Westerlies in South America
Gilli, Adrian; Ariztegui, Daniel; Anselmetti, Flavio S.; et al. (2005)
Global and Planetary Change
The nexus among long-term changes in lake primary productivity, deep-water anoxia, and internal phosphorus loading, explored through analysis of a 15,000-year varved sediment record
Tu, Luyao; Gilli, Adrian; Lotter, André F.; et al. (2021)
Global and Planetary Change
Increased cultural eutrophication since the 20th century, caused by phosphorus (P) enrichment, has become a major problem worldwide. In deep, stratified lakes, eutrophication-induced hypolimnetic anoxia often stimulates the release of labile P from the sediment into the water column. This positive feedback, termed internal P loading, maintains or even accelerates eutrophication. However, most studies on internal P loading have focused on recent times. Little is known about whether such positive feedbacks caused by labile P release from sediments also played a role under natural conditions with little or no human impact. We investigated a high-resolution 15,000-year sediment record of paleoproduction, anoxia, and five sedimentary P fractions from a small, deep lake, Soppensee, on the Swiss Central Plateau. We estimated long-term qualitative internal P loading by comparing the Holocene record of diatom-inferred epilimnetic total P (DI-TP) concentrations with labile P fraction (Fesingle bondP) concentrations in sediments under changing trophic state, redox, and lake mixing regimes. Intensified P cycling from sediments into the water column (enhanced internal P loading) apparently occurred as a positive feedback to natural eutrophication with persistent bottom-water anoxia during the early to mid-Holocene (~9000–6000 cal BP). However, this positive feedback was not inferred for other eutrophic phases. Fe-rich layers formed during seasonal mixing of the lake in the late Holocene (~2000–200 cal BP) and magnetite-type minerals produced by magnetotactic bacteria (MTB) internal P loading during anoxic phases in the mid- to late Holocene (~6000–2000 cal BP) appeared to prevent internal P loading. MTB presence resulted in high concentrations of potentially labile Fesingle bondP in sediments. Our study demonstrates the potential contribution of internal P loading during long-term natural eutrophication of deep stratified lakes and has wide implications for lake management and restoration. Our results highlight the importance of the coupled geochemical cycles of P and Fe in the long-term trophic state evolution of stratified, ferruginous, low-sulfate-water lakes, conditions that have been reported to serve as analogs for the Archaean Ocean.
Impact of recent lake eutrophication on microbial community changes as revealed by high resolution lipid biomarkers in Rotsee (Switzerland)
Naeher, Sebastian; Smittenberg, Rienk H.; Gilli, Adrian; et al. (2012)
Organic Geochemistry

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Adrian Gilli

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