bluuebunny/crossref_metadata_2025 huggingface dataset:
Fault segmentation, off-fault deformation, and fault maturity
Authors: Klinger Yann
Published: March 2024

Large continental strike-slip earthquakes produce significant surface ruptures, tens to hundreds of kilometers long, with displacement that can reach several meters, depending on the magnitude of the earthquake. However, this information, and more specifically the detail of the surface ruptures has long been overlooked, as we missed efficient ways to document extensive ruptures. In the last decade, with the emergence of new remote sensing tools, our community came to realize that earthquake surface ruptures could bear significant information about fault structure and the way deformation is accommodated during earthquakes. Hence, through a systematic survey of surface ruptures, based on field observation and remote sensing data, we demonstrate that it is possible to define a fault segmentation that would not be arbitrary, but instead is related to some first-order characteristic of the brittle crust, the thickness of the brittle crust, also called the seismogenic thickness. This observation result has been tested and confirmed through a series of analogue and numerical experiments that allowed us to systematically study fault segmentation when varied the thickness of the brittle material. We also questioned the distribution of deformation along those fault segments during earthquakes, as the development of high-resolution image correlation technics gives us access to a more detailed picture of the ground deformation distribution around large strike-slip earthquake ruptures. More specifically, we have been able to show that in some places a significant part of the deformation is distributed off fault, up to 30%, accommodated by micro-cracks, or even in the bulk. This deformation is almost impossible to measure in the field and thus is not considered in classic models of earthquake source inversion. It might in fact be the reason why many models involve some shallow slip deficit, which is physically not understood, while it might only be an artefact of modeling. Eventually, the evolution through time of fault geometry and off-fault deformation is questioning the long-term evolution of fault geometry, a potential proxy for fault maturity. Here we show through analogue experiments that in fact, once a growing fault system has gone pass through a localization stage, where distributed deformation is drastically reduced, the fault system never simplifies further and keeps having some level of complexity associated with a steady amount of distributed deformation close to 20%, independently of the total amount of deformation accommodated by the fault system, suggesting that a fault system can probably be considered definitively mature almost immediately after its localization stage, for a small amount of total displacement.
Inferring climatic sea-level variations from microatolls in tectonically active regions
Authors: Debaecker Sophie , Karpytchev Mikhail , Becker Mélanie , Feuillet Nathalie , Satake Kenji
Published: March 2024

Coral microatolls are often used to reconstruct the relative sea-level (RSL) along tropical coastlines. They grow at a constant rate, developing each year a growth band that can be observed in their internal stratigraphy. As their development is limited by the water height, they record annual variations of the relative sea-level once they have reached the sea surface. These changes are related to both climate and tectonic, and several criteria are used to decipher both signals. For example, it is commonly accepted that a local signal would rather correspond to a tectonic event, and inversely. However, majority of the criteria such as regrowth of the coral, amplitude of the RSL anomaly or matches with seismic or climatic events catalogs are mainly qualitative and most of the time, incomplete. In our study, we seek to develop a mathematically sound method to separate the climatic signal recorded by a series of microatolls. We focused on the region of the Ryukyus islands in south-west Japan, where the Philippine sea plate plunges under the Eurasia plate. In this area, up to 15 modern and living corals have been collected previously; and their RSL records extend from 1762 to 2018. They extend over 900 km along the subduction zone. Despite the seismic activity of the area, it is possible to infer that any signal common to all microatolls can be considered as climatic. We used a statistical method over the corals dataset to extract a common-mode RSL signal over the island arc. We found a long term sea-level rise for the last 200 years. We further analyze shorter time trends and annual anomalies, and compare our results from the RSL records that include years where only minimum RSL was recorded. Additionally, to refine our method we aim to compare sea level changes recorded by tide gauge in the Ryukyus with the estimates from inferred from the coral microatolls from seismically stable regions in the Pacific Ocean.
Diversity of seasonal cycle anomalies of surface air temperature in winter over China 
Authors: Yu Minjie
Published: March 2024

The seasonal cycle (SC) anomalies of winter surface air temperature (SAT) over China mainly include three modes: consistent changes throughout the winter, inverse changes in the early and late winter, and opposite changes in the southern and northern China, respectively.  The positive EOF1 phase (i.e., uniformly warming throughout winter) can be attributed to global warming, especially in the North Atlantic and tropical Pacific. The EOF2 is mainly related to the dipole sea surface temperature (SST) pattern in the North Atlantic. In the early winter, the Rossby wave originating from North Atlantic strengthens Ural blocking high (UBH) and Siberian high (SH) in the early winter, resulting in cold SAT anomalies in most of China. While the large-scale zonal circulation with weakened SH has transformed SAT over China into a warm state in the later winter. The EOF3 can be attributed to the tripole SST in the North Atlantic and El Niño-like SST pattern in the tropical Pacific. In December, the Rossby wave train originating from the mid-latitudes of the North Atlantic Ocean enhances cold air activity in the Northern Hemisphere, causing cold SAT anomalies in Northeast China, while the dominating southerly winds in southern China cause warm SAT anomalies. In the late winter, the large-scale circulation resembles negative AO phase, resulting in the northerly winds and cold SAT anomalies in the northern China. Meanwhile, the anomalous anticyclonic circulation in the Northwest Pacific causes warm SAT anomalies in southern China. Therefore, the combined effects of tropical and extratropical SST should be considered when predicting interannual variability of winter SAT anomalies over China.
Linking the interior structure of terrestrial exoplanets to their (tidal) observables
Authors: Walterová Michaela , Běhounková Marie
Published: March 2024

Tidal effects probe the interior of celestial bodies and are an important source of information on their thermal state and the prevailing deformation mechanisms. In the case of exoplanets, estimation of quantities related to tides might add important constraints on the interior structure of those worlds that would complement the existing measurements of masses and radii [e.g., 1]. In recent years, the fluid Love number hf, which characterises the deformed figure of a rotating celestial body, has been measured for the gaseous exoplanet WASP-103b [2], and the rate of tidal dissipation has also been estimated for several extrasolar gas giants [e.g., 3]. Although not directly detectable today, future measurements might also assess the deformation of Earth-sized exoplanets. Moreover, the measurements of thermal emission light curves, accessible to JWST [4], might shed light on the actual spin states of low-mass exoplanets, which is another parameter affecting the long-term evolution and the habitability prospects of the extrasolar worlds. Detailed analysis of the light curves can also unveil global-scale volcanism that would be indicative of the magnitude of tidal dissipation [5].Here, we discuss and illustrate the link between various aspects of the planet’s interior structure and a set of potential observables related to tides on close-in rocky exoplanets without atmosphere. Specifically, we focus on the role of different rheological models and their parameters and on the major features of the interior structure, such as liquid layers or low-viscosity zones. We address the stability of various spin-orbit resonances, surface tidal heat flux, the magnitude of the tidal Love numbers h2 and k2, and the present-day effect of tides on the orbital elements. Since the tidal deformation and the rate of energy dissipation in close-in rocky exoplanets also govern the secular orbital evolution, we further discuss the effect of changes in the interior structure, induced by variations in the thermal state, on the long-term orbital dynamics of tidally loaded exoplanets or moons [6]. Acknowledgement:The work presented in this contribution has been supported by the Czech Science Foundation grant nr. 23-06513I. References:[1] Baumeister & Tosi (2023), doi:10.1051/0004-6361/202346216.[2] Barros et al. (2022), doi:10.1051/0004-6361/202142196.[3] Barker et al. (2024), doi:10.1093/mnras/stad3530.[4] Zieba et al. (2023), doi:10.1038/s41586-023-06232-z.[5] Selsis et al. (2013), doi: 10.1051/0004-6361/201321661.[6] Walterová & Běhounková (2020), doi:10.3847/1538-4357/aba8a5.
Microstructural insights during Abrupt events
Authors: Sanchez Moreno Miguel , Lamott André , Kipfstuhl Sepp , Dahl-Jensen Dorthe
Published: March 2024

The physical properties of ice crystals are strongly related to the flow and deformation of ice. This has been established by detecting crystal size and crystal orientation on 10cm x 10cm thin sections of ice through many of the deep ice cores by microstructure mapping. This method maps etch grooves on polished and sublimated surfaces at microscopic resolution generated by the Extra Large Area Scanning Microscope (xLASM) and allows for a detailed investigation of deformation-induced microstructural features. 

Here, we carry out a detailed examination of the microstructural features present along 25 meters of ice within the North Greenland Eemian Ice Drilling project (NEEM). The study analyzes ice from 2003 meters to 2028 meters in depth, covering three abrupt events (GI-19.2, GS-20, and GI-20) within the Last Glacial Maximum. In combination with fabric measurements and borehole logging data, we aim to understand shifts in ice rheology and flow dynamics during these abrupt events. 
Probability distributions as indicators of dissipative dynamics in river chemistry
Authors: Gozzi Caterina , Kleidon Axel , Buccianti Antonella
Published: March 2024

The chemistry of rivers plays a crucial role in comprehending the evolution of weathering processes, especially in the context of climate change and human activities. As weathering proceeds within river catchments, chemical concentrations tend to move towards saturation, or thermodynamic equilibrium. However, thermodynamic equilibrium is extremely difficult to achieve in an open system where matter and energy are continuously exchanged.The speed of weathering processes and the associated probability distributions of concentrations values differ among geochemical species. We demonstrate that these differences are characterized by the rate of entropy production associated with the mixing of groundwater enriched with weathering products with the less saturated river water.Based on river chemistry and discharge data observations in the Arno River basin in central Italy, we distinguish two groups of chemical variables, reflecting different levels of dissipative behavior. We show that Calcium (Ca2+) and Bicarbonate (HCO3-) concentrations are close to saturation along most of the downstream length of the Arno River, with decreasing dissipation rates and a (log)normal distribution, while Sodium (Na+) and Chlorine (Cl−) concentrations increase substantially downstream, showing increased dissipation rates and being power-law distributed. This supports our hypothesis that power law distributions appear to be indicative of dissipative systems far from thermodynamic equilibrium, while (log)normal distributions indicate weakly dissipative systems close to equilibrium. This suggests that the frequency distributions of environmental variables are intricately connected to their thermodynamic state, and the degree of disequilibrium constrains the range over which power-law scaling can be observed. These results should contribute to a more comprehensive understanding of the characteristics and underlying mechanisms that lead to these types of distributions, allowing to better classify variability in systems based on how dissipative they are.
SMASH: a constellation of small altimetry satellites to monitor daily inland surface waters
Authors: Biancamaria Sylvain , Calmant Stephane , Frappart Frederic , Garambois Pierre-Andre , Gosset Marielle , Grippa Manuela , Kouraev Alexei , Malaterre Pierre-Olivier , Munier Simon , Papa Fabrice , Yesou Herve , Amiot Thierry , Cheymol Cecile , Le Gac Sophie
Published: March 2024

At global scale, there is still considerable uncertainty about the spatial and temporal variability of water storage and fluxes at the surface of continents. This is even more critical in the context of global climate change and the increasing human pressure on water resources. Despite this context, the following scientific questions remain difficult to answer, due to the coarse spatio-temporal resolution of current data: what is the global distribution of the heterogeneous change undergone by continental surface waters? What is the impact of anthropogenic pressure on water flows and stocks? What is the impact of these changes on the frequency and intensity of hydrological extremes (high and low waters)? To answer these questions, the Global Climate Observing System (GCOS) has identified river levels/discharges and lake/reservoir levels/volumes as essential climate variables, and recommends daily sampling (GCOS, 2022). Besides, extreme events, such as floods or droughts, cover a wide range of spatio-temporal scales. At present, water volume variations can only be observed by satellite at the coarsest scales (and are therefore of interest only for floods on the scale of the world's largest watersheds). The lack of observation of these events in basins with little or no in situ instrumentation is a major issue to understand, simulate and forecast these events. Observing these events globally, at least on a daily scale, would make it possible to quantify local flooding, thus greatly improving our knowledge of these events.
One of the main issue to tackle these questions is the still rather coarse temporal sampling of current satellite missions, particularly altimetry missions. To overcome it, we are proposing the SMall Altimetry Satellites for Hydrology (SMASH) mission. This is a constellation of around 10 compact nadir radar altimeters optimized to provide daily observations of water levels in rivers, lakes and reservoirs along the constellation tracks. The specifications of the SMASH mission are the following: daily temporal sampling, observe water bodies larger than 100 m x 100 m and rivers as narrow as 50 m, with an accuracy on water elevation ~10 cm, and should provide products in near-real time and over the long term (10 years) in open access (open science and FAIR principles).
Combining "high temporal frequency/low spatial frequency" measurements from the SMASH mission with "high spatial frequency/low temporal frequency" measurements from swath altimetry missions (current SWOT or futur Sentinel-3 Next Generation Topography missions) would cover unprecedented time and space scales and should open new fields of research.
Status of the Circumpolar Landcover Unit database
Authors: Khairullin Rustam , von Baeckmann Clemens , Bartsch Annett , Bergstedt Helena , Widhalm Barbara , Efimova Aleksandra , Muri Xaver , Ermokhina Ksenia , Heim Birgit
Published: March 2024

The Circumpolar Landcover unit database provides landcover information in high detail, spatially (10m) and thematically (23 units). Such detail is needed for a wide range of applications targeting climate change impacts and ecological research questions. The landcover unit retrieval scheme used provides unprecedented detail. The landcover units have been derived by fusion of satellite data using Sentinel-1 (synthetic aperture radar) and Sentinel-2 (multispectral). The units reflect gradients of moisture as well as vegetation physiognomy. The original database covered the Arctic north of the tree line. It has been extended towards south, providing additional detail within the tundra-taiga transition zone in permafrost regions. The available spatial detail provides the means to assess the complexity of this zone in addition to information on recent disturbance related to for example wildfire and thermokarst lake change. Bartsch, A., Efimova, A., Widhalm, B., Muri, X., von Baeckmann, C., Bergstedt, H., Ermokhina, K., Hugelius, G., Heim, B., & Leibmann, M. (2023). Circumpolar Landcover Units (1.0) [Data set]. Zenodo. https://doi.org/10.5281/zenodo.8399018
 Soil microbial based strategies and seed enhancement technologies reconnect plant-soil biodiversity and improve restoration outcomes 
Authors: Muñoz-Rojas Miriam , Dadzie Frederick , Machado de Lima Nathali
Published: March 2024

Soil microorganisms control important ecosystem functions such as nutrient cycling, plant productivity and climate regulation. Thus, microbially assisted conservation and restoration has the potential to reconnect above and belowground dynamics, creating functional ecosystems that are more resilient to climate change impacts. In this research, we (i) assessed the responses of soil microbial communities to disturbance, e.g., severe fire, and extractive activities such as mining, and (ii) developed bioinoculants composed of locally sourced soil bacteria from the rhizosphere and biocrust cyanobacteria, to promote plant growth and soil fertility and enhance ecosystem capacity for global change adaptation. This presentation will showcase some key findings of these studies conducted in contrasting Australian ecosystems (shrubland-grassland in the arid zone, and subtropical/temperate forests). These outcomes include the successful translocation of whole-soil communities for inhibiting weeds, and the effective use of indigenous microbes (rhizobacteria and cyanobacteria combinations) for soil carbon sequestration, nitrogen fixation, and growth promotion of key arid and temperate plant species.Overall, our research demonstrates the benefits of using native microbial communities as bioinoculants in ecosystem restoration. The emerging technologies used in our research, i.e. seed enhancement through seed biopriming and biopellets, have a large potential for landscape-scale conservation and restoration programs in the context of global change.
Impact of Uncertainty on the Choice of Long-Term Flood Protection Option under Climate Change
Authors: Mavrova-Guirguinova Maria
Published: March 2024

The subject of the study is the considerable uncertainty in determining flood risk when long-term climate change projections are developed. Risk management decision-making involves comparing options based on their benefits and costs. The purpose of the analysis is to reveal the uncertainty robustness of alternative flood protection measures. The treatment of different sources of uncertainty is done by using probabilistic net present value (NPV) analysis as well as by using Information-gap decision theory (IGDT). The case study is a settlement in northern Bulgaria with a record of severe flooding in the past, for which different climate change projections are generated under RCP 4.5 and RCP 8.5 scenarios. The behaviour of three civil protection options under these uncertainty conditions is investigated for an extended 30-year time period to 2050. A probabilistic analysis with NPV performance criterion is performed sequentially, followed by Info-gap decision theory analysis.After discussing the results, the advantages and disadvantages of the two methods are compared. Some limitations and advantages of the Information gap theory are discussed. Finally, it is highlighted that when making decisions about long-term flood protection, it is recommended to use multiple methods that differ in data and assumptions, necessarily taking into account the hydrological uncertainty arising from climate change, which can radically change our choices.
Soil moisture forecast based on gridded historical and forecast datasets
Authors: Saboori Mojtaba , Jalali Shahrood Abolfazl , Ghag Kedar , Klöve Björn
Published: March 2024

Continuous monitoring of soil moisture (SM) has become a prevalent approach in precision irrigation control. Fluctuations in SM within the root zone, whether caused by overly wet or dry conditions, can potentially diminish plant transpiration, leading to decreased productivity. Hence, ensuring a timely and appropriate supply of water is essential for effective irrigation management. Though various machine and deep learning models, along with in-situ climate data, have been examined for monitoring SM, the incorporation of gridded historical and forecast climate data into this aspect has not been explored. In this research, we assess forecasting SM by Random Forest (RF) model for the next 7 days using two approaches: A) relying on forecasted data for each day, and B) relying solely on historical data. To this end, the gridded climate data (air temperature, relative humidity, wind speed, precipitation, and reference evapotranspiration-ET0), the soil features (lagged in-situ SM and gridded soil temperature), and vegetation features (Normalized Difference Vegetation Index-NDVI) for different land covers in Oulu, Finland. The findings suggest that using gridded data could be a promising option in places where there is limited data for the SM forecasting. The lagged SM was the most explaining variable, followed by soil temperature, NDVI, and ET0. Furthermore, both scenarios exhibited similar trends, showing a decline in forecasting accuracy as the lead time approached 7 days, and thus scenario B can provide more efficient SM forecasts.
Toward large-scale demonstration of local multi-hazard early warning tools
Authors: Park Shinju , Marc Berenguer , Sempere-Torres Daniel
Published: March 2024

Catalonia is located in north-eastern Spain and in a predominantly subtropical Mediterranean climatic zone. Due to the diverse geographical and orographic features, the climate within the region exhibits variations due to local continental, oceanic, and alpine influences.Within the Horizon Europe RESIST project (2023-2027), Catalonia is one of the leading regions for the demonstration of climate change adaptation strategies toward climate change resilience through innovation, science, and technology. The strategies being analyzed in Catalonia focus on the sector of civil protection to achieve improved preparedness and tools for disaster risk and emergency management for weather-related hazards (e.g., flash floods, wildfires, heat waves, etc.).The presentation will address the key enabling tools and activities toward better adaptation; e.g., improving and expanding the existing Multi-Hazard Early Warning System (EWS) over Catalonia, improving the assessment of vulnerabilities and including vulnerable communities, raising awareness. These aspects will be evaluated during a long-term demonstration in several local municipalities of the region. The first results obtained during 2023 will be presented; particularly for the major flood event in June 2023 in Terrassa city.
Plastic quantification and limitations in different soil types using large-volume pyrolysis and TD-GC-MS/MS
Authors: Bartnick Ryan , Rodionov Andrei , Oster Simon David Jakob , Löder Martin G. J. , Lehndorff Eva
Published: March 2024

It is a continuing challenge to analyze plastic in soil on an environmentally relevant level given the large variety and complexity of soil composition. Improvement of methods is required to: increase sample volume to meet soil heterogeneity, and simultaneously detect and quantify different types of plastic with high accuracy and precision independent of soil properties. A new combination of large-volume pyrolysis with thermal desorption-gas chromatography-tandem mass spectrometry (TD-GC-MS/MS) was used to detect a variety of polymer types without prior clean-up in larger (>1 g) soil samples. Characteristic MS/MS profiles for PA, PBAT, PE, PET, PLA, PMMA, PP, and PS were derived from plastic pyrolysis. Specifically developed rectangular, volume-defined reference micro-particles with respective weight (PE 0.48±0.12, PET 0.50±0.10, PS 0.31±0.08 µg), which can be directly introduced into solid samples for pyrolysis, were used as internal standards. For PE quantification in soil, we suggest a mathematical correction, PEcorrected, when analyzed without clean-up to account for organic matter contribution. In soil with organic carbon >1.5%, PE detection would require removal of organic matter. With a standard addition method, we quantified PS, PET and PEcorrected in complete soil matrices. To evaluate the reproducibility of plastic quantification for soils with different properties, sandy, clayey, oxide-rich and soils rich in organic matter were tested. We can now give recommendations for a simplified, more time-efficient quantification of various plastic types in a range of soil matrices and, hence, provide a robust base for future studies on the fate and effect of plastic in the environment.
Characterisation of algal blooms on seasonal snowfields through a combination of field spectrometry, drone imagery and radiative transfer modeling at Hardangerjøkulen (Hardanger glacier), Southern Norway
Authors: Chevrollier Lou-Anne , Wehrlé Adrien , M. Cook Joseph , M. Anesio Alexandre , G. Benning Liane , Tranter Martyn
Published: March 2024

Pigmented microalgae bloom on glaciers and snowfields worldwide, contributing to carbon storage and enhanced surface melt through surface darkening. The darkening impact of snow algal blooms is being increasingly studied on terrestrial glaciers and ice sheets but less attention has been given to seasonal snowfields, despite their ecological and climatic relevance. Algal blooms are typically widespread but heterogeneously distributed and therefore high resolution airborne observations provide important insights to better understand the spatial patterns and impact of the blooms. Here, we present 130 field spectra colocated with low-cost and light-weight drone imagery acquired over 6 different snowfields in July and August 2023 around Hardangerjøkulen (Hardanger glacier), Southern Norway. We combine these high-resolution measurements with radiative transfer modeling to provide estimates of abundance, carbon storage and albedo impact of snow algal blooms on seasonal snowfields.
Interdisciplinary Insights into the Island Mass Effect of the Cape Verde Archipelago
Authors: Schuette Florian , Hans Anna Christina , Schulz Marco , Brandt Peter , Hummels Rebecca , Körtzinger Arne , Fiedler Björn , Fischer Tim , Hoving Henk Jan , Hauss Helena
Published: March 2024

The Cape Verde Archipelago (CVA) stands out with exceptional biological productivity sustaining a highly diverse ecosystem. Higher primary productivity in the proximity of islands, known as the Island Mass Effect (IME), has been systematically observed on global scale but the details of the interplay between physical and biogeochemical processes remain not fully understood. Within this study, a comprehensive analysis of the IME within the CVA based on 20 years of physical, chemical, and biological observational data sets is presented for the first time. Three main physical processes are identified to be responsible for the IME of the CVA and are investigated in detail: I. The interactions of tidal flows/internal waves with topography: Internal wave breaking at critical slopes leads to elevated mixing rates of a factor 100 larger than at reference points. II. The generation of island wakes in lee of Santo Antãoand Fogo: wind interactions with the island’s topography cause local wind shear in lee, which can generate productive vortex patterns extending for several island diameters downstream. III. The interaction of remotely-generated mesoscale eddies with the CVA itself: After central collision of open ocean eddies with islands or seamounts or when the eddy passes by very closely, we observe submesoscale frontal dynamics driven by mesoscale flow brought out of geostrophic balance, thereby enabling vertical mixing hotspots. Our observations particularly show the interactions between eddies and the internal wave field (modified by vertical shear of the mesoscale eddy, tides, bathymetry, or a combination of all these factors).All these mechanisms (I., II., and III.), albeit diverse, uniformly augment vertical exchange by turbulent motions with strongly enhanced diapycnal mixing rates and/or vertical velocities and thereby promote elevated nutrient flux into the euphotic layer. This flux ultimately results in significantly higher phytoplankton concentrations in areas where these physical processes occur, thus providing the basis of the local pelagic food web consisting of mesozooplankton and micronecton up to larger predators.
Can contamination indices performance be improved by accounting for the dilution effect when dealing with stream sediments? A case study from southern Italy.
Authors: Iannone Antonio , Guarino Annalise , Pacifico Lucia Rita , Albanese Stefano
Published: March 2024

Geochemical prospecting is a valuable tool for investigating the influence of the geological context on the composition of stream sediment and determining the existence of any natural or anthropogenic geochemical anomaly within a river catchment basin. Several indices have been proposed in scientific literature to assess sediment's environmental quality and the ecological condition of catchment basins. In environmental studies, these indices are usually based on applying ratios among the raw geochemical composition of the sediment at the sampling location and a value assumed as a reference for the undisturbed conditions (Background/baseline). However, the reference values are often determined while overlooking the potential influence of river dynamics on the variability of sediment composition, and this can compromise the robustness of the contamination assessment.As a matter of fact, the chemical composition of a stream sediment sample is representative of the relative upstream catchment basin. The Sample Catchment Basin (SCB) method, which accounts for the dynamic nature of rivers, has been largely used in literature to correct the dilution effect impacting the composition of stream sediment, aiming at determining reliable geochemical background values to be used for mineral prospecting.The main purpose of the study was to check if the use of the correction of the dilution effect to determine background values could also improve the performance of some contamination indices, favouring a more effective and accurate assessment of the environmental degradation affecting a river basin.The Sarno River, known for its susceptibility to contamination from urban and industrial sources, served as a pertinent case study. A total of 96 samples were used to define the zone of influence of each sample through the elaboration of geomorphological and hydrological features; then, the background concentrations of each element were estimated by calculating the weighted average element content based on the areal proportions of lithologic units in each sample catchment basin. The values deriving from this step were then used as a reference to calculate the degree of contamination for each SCB.The contamination indices were calculated and mapped by using both non-diluted and dilution-corrected background data.A comparative analysis was performed among the results obtained to assess if sensitive changes occurred to the spatial and statistical distribution of used indices and to determine if an improvement in performance could be obtained. This study represents a methodological benchmark for future research focusing on environmental risk assessment of stream sediment.
Leaf thermoregulation and fog wetting dynamics of Erica platycodon in a Macaronesian cloud forest
Authors: Regalado Carlos M. , Garcia-Tejera Omar , Ritter Axel
Published: March 2024

Interception of fog droplets in cloud forests leads to wetting of the canopy, hampering transpiration and affecting the energy dynamics of the vegetation due to evaporation of the leaf water lamina and the reduction in the incoming solar radiation. We carried out continuous concurrent measurements of the canopy temperature (through infrared thermometers), artificial leaf wetness (LWS) and the micrometeorology of a cloud forest in the Anaga Biosphere Reserve (Tenerife, Canary Islands) during a 4-month period. Fog presence at the site, characterized by visibility measurements (Ω), was coincidental with variations in LWS and a decline in net solar radiation, Rn, i.e. 62.2 W m-2 during foggy conditions (Ω < 1 km) versus 245.0 W m-2 for fog-free conditions (Ω ≥ 1 km). Infrared readings during foggy conditions of one of the representative species of the cloud forest stand, the perennial tree Erica platycodon, showed that differences between canopy and ambient temperatures were primarily driven by Rn. After a fog event, E. platycodon was estimated to remain wet for at least 30 minutes up to 2.25 hours. This study provides information about the consequences of fog in the wetting/drying dynamics of cloud forests of the Canary Islands and their leaf thermoregulation.
GWMicroPlast project – researching microplastics in groundwater
Authors: Kovač Viršek Manca , Bizjak Tine , Colmenarejo Calero Elvira , Zabret Katarina , Koroša Anja , Miler Miloš , Mali Nina
Published: March 2024

Microplastics are recognised as an emerging pollutant. Microplastics describe plastic particles between 1 µm and 5 mm, which may be produced in this size (primary microplastics) or originate from bigger plastic debris subjected to decay or wear in the environment (secondary microplastics). Research in the field of microplastics started in the marine environment over 60 years ago but has been focusing on other environments only for the past 25 years. Microplastic particles have been observed almost everywhere – in oceans, rivers, wetlands, groundwater, lakes, air, plants, animals and people. Water is identified as the main transport medium of microplastics, however, only a few more recent studies identified microplastics in groundwater. Groundwater is an important drinking water resource in many parts of the world, e.g., in Slovenia, 98 % of drinking water demands are covered by groundwater resources.This contribution gives the main subject of the ongoing research project GWMicroPlast, within which we will investigate the entire pathway of the microplastics and other pollutants linked with plastics pollution through the aquifer, starting from potential sources to the transport in the unsaturated zone and saturated zone and focusing on the evaluation of the presence of microplastics in different groundwater zones and on the improvement of understanding of microplastics migration through the aquifer. Within the scope of the proposed project, we aim to check the status of microplastic pollution in all three types of drinking water aquifers, intergranular, karst and fissured, in Slovenia. Special attention will be paid to developing methods for sampling and analysing microplastics in groundwater for different aquifers. The transport processes of microplastics in the gravel unsaturated zone will be investigated in more detail by a tracing experiment in the lysimeter.  Acknowledgement: This contribution is part of the ongoing research project entitled “Improved methods for determination of transport processes and origin of microplastics in groundwater resources – (GWMicroPlast)” supported by the Slovenian Research and Innovation Agency (J1-50030).
Summer Deep Depressions Increase Over the North Atlantic
Authors: D'Andrea Fabio
Published: March 2024

Mid-tropospheric deep depressions in summer over the North Atlantic are shown to have strongly increased in the eastern and strongly decreased in the western North Atlantic region.  This evolution is linked to a change in baroclinicity in the west of the North Atlantic ocean and over the North American coast, likely due to the increased surface temperature there. Deep depressions in the Eastern North Atlantic are linked to a temperature pattern typical of extreme heat events in the region. The same analysis is applied to a sample of CMIP6 model outputs, and no such trends are found.  This study suggests a link between the observed increase of summer extreme heat events in the region and the increase of the number of Atlantic depressions. The failure of CMIP6 models to reproduce these events can consequently also reside in an incorrect reproduction of this specific feature of midlatitude atmospheric dynamics.
Subgrain-size piezometry of feldspar and quartz records a single paleostress from dry lower continental crust
Authors: Osinchuk Alix , Dyck Brendan , Wallis Dave , Camacho Alfredo
Published: March 2024

Strength-depth profiles for ductile portions of continental crust are derived from either extrapolation of flow laws from deformation experiments or paleopiezometric estimates in deformed and nominally hydrated plate margins. Lower continental crust in intracontinental settings, in contrast, is relatively dry and should be considerably stronger than the lower crust of hydrated plate margins. The relative strengths of dry quartz and feldspar are poorly constrained by experiments and paleopiezometric estimates from such rocks are sparse. As such, the strength of intracratonic lower crust is difficult to ascertain. Here, we use a recently calibrated subgrain-size piezometer to estimate paleostresses from feldspar and quartz deformed in relatively dry (
Exploring microbial PFAS degradation at two contaminated firefighting training sites in Sweden
Authors: Messinger Nicola , Ahrens Lutz , Bertilsson Stefan , Berggren Kleja Dan , Fagerlund Fritjof
Published: March 2024

The extensive use of Aqueous Film Forming Foam (AFFF) has led to substantial contamination by per- and polyfluoroalkyl substances (PFAS) of soils and groundwater at many firefighting training sites in Sweden and worldwide. PFAS is a group of extremely persistent anthropogenic substances that pose risk for adverse effect even at low levels. There is consequently a need to understand the potential for natural degradation of these compounds and the controlling environmental factors. Understanding the microbial capacity to degrade and transform PFAS is also crucial for comprehending their transport in soil and groundwater and for the development of a potential bioremediation technique. Despite commonly referred to as “forever chemicals”, there is emerging evidence of PFAS being microbially degraded in laboratory settings. The aim of this study is to investigate the microbial degradation capacity of the natural bacteria at two firefighting training sites (FFTS) contaminated with PFAS. Utilizing a sonic drill, soil samples were collected from both above and below the water table from FFTS near Örnsköldsvik and Sundsvall Timrå airports in Sweden. Enrichment cultures were initiated by mixing these soil samples with four different growth media—two for aerobic and two for anaerobic incubations. The incubation conditions, aerobic or anaerobic, were determined dependent on if the sample was taken above or below the groundwater level. All incubations were spiked with perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), 6:2 fluorotelomer sulfonic acid (6:2FTSA) and perfluorooctane sulfonaminde (FOSA) to reach a concentration of 9ppm. Samples from the incubations were taken at monthly intervals to screen for fluoride production, as an indicator for PFAS degradation, using ion chromatography. Using this approach, we aim to uncover the capability of the natural microbial community at these sites to degrade PFAS. In the second phase of this study, this will be followed by careful analysis of degradation products with the aim to identify degradation pathways.
Comparative simulations of Kelvin-Helmholtz induced magnetic reconnection at the Earth's magnetospheric flanks
Authors: Ferro Silvia , Faganello Matteo , Califano Francesco , Bacchini Fabio
Published: March 2024

In this work, we investigate the interaction between the solar wind and the Earth’s magnetosphere by conducting 3D Hall-MHD simulations. Specifically, we focus on the development of the Kelvin-Helmholtz instability (KHI) and its crucial role in driving magnetic reconnection and plasma transport at the magnetopause. The KHI is closely linked to plasma turbulence, as turbulent fluctuations contribute to its growth by facilitating energy transfer and mixing at smaller scales and the KHI itself is a driver for turbulence in plasma dynamics. At Earth's magnetopause, this leads to increased vortex and wave activity and the emergence of secondary KH modes. Our work involves analyzing simulation data and comparing the effects of initial magnetic shear on the development of the KHI. The results show that the presence of magnetic shear significantly influences the latitudinal distribution of vortices and magnetic reconnection events, leading to quantitative differences in the system’s evolution. Despite differences in the global magnetic topology, all simulations exhibit the formation of vortices, secondary KH instabilities, and a turbulent mixing layer during the late nonlinear phase of the instability.
Exploring key issues in public engagement and activism. Findings of a working group at the University of Lausanne.
Authors: Fragnière Augustin
Published: March 2024

The growing involvement of researchers in the public debate is triggering reflections in various scientific institutions. Here we report on the reflections of a working group of the University of Lausanne (UNIL) gathering researchers from all faculties, coordinated by the Competence Centre in Sustainability (CCD) and the Interdisciplinary Centre for Ethics Research (CIRE). Commissioned by UNIL’s Rectorate, the working group met thirteen times between April 2020 and May 2022 and independently defined the themes, approaches and methods that it deemed relevant to mobilize in this perspective. In particular, it conducted a literature review, a survey and focus groups with the UNIL community in the spring of 2021.The working group's reflections were primarily aimed at clarifying the issues related to the engagement of scientists in the public debate and at better understanding the practices and perceptions of the UNIL community in this respect. They also aimed to propose answers to questions such as: should researchers be free to engage in public advocacy and activism? Is this compatible with the swiss legal framework and with notions such as science neutrality and academic freedom? What good practices should be followed when engaging in advocacy and/or activism? How should UNIL, as an institution, support its engaged researchers?The main conclusion of the working group, published in a report in May 2022, is that participation in the public debate, advocacy and activism is compatible with research activities and as such should be supported by the academic institutions. However, it recommends a few good practices such as being as transparent as possible about the role that is endorsed (expert, researcher, activist, etc.) and about the nature of the statements that are made in public (scientific findings, personal opinion, political recommendation, etc.). In this brief oral, I will delve into the main conclusions of the working group’s report and address the questions mentioned above.
Statistical methods for estimating the forced component of historical SST and precipitation changes: A bias-variance tradeoff
Authors: Höver Maren , Jnglin Wills Robert , Fahrenbach Nora
Published: March 2024

Distinguishing the influences of externally forced responses and internal variability on the observed climate is critical for attributing historical climate change and for evaluating the forced responses simulated by climate models. Statistical methods such as optimal fingerprinting, low-frequency component analysis (LFCA), and dynamical adjustment have proven useful for this application. The skill of such statistical methods can be evaluated using climate model large ensembles, where the forced response is estimated by averaging over many realizations. Our study uses large ensemble simulations from five different climate models to evaluate the performance of three statistical methods for this application: (1) low-frequency component analysis, (2) signal-to-noise maximizing pattern optimal fingerprinting (SNMP-OF), which uses the patterns from an ensemble-based signal-to-noise maximizing pattern (SNMP) analysis for optimal fingerprinting, and (3) a novel method based on SNMP analysis called fingerprint maximizing patterns (FMP), which finds patterns within observed variability that have the maximum fingerprint of the model-based forced response. We investigate how the root mean square error (RMSE) of these three methods varies across the choices of hyperparameters and show that all methods have a similar maximum skill. However, the contribution to the RMSE from the mean bias in the forced response estimate varies across the methods, with SNMP-OF and FMP showing a larger mean bias than LFCA. This demonstrates that methods that largely rely on the model forced response to obtain the observed forced response may give biased estimates and underestimate the uncertainty in these estimates due to the bias-variance tradeoff. Additionally, we apply these methods to observed Sahel precipitation, which is extensively debated in terms of its forced component, and closely related North Atlantic sea surface temperatures (SSTs). We show that while the methods give a robust estimate of the forced response in North Atlantic SSTs from 1950 to 2022, their estimates of the forced response in Sahel precipitation over the same period differ in sign. The fact that these estimates of the Sahel precipitation response differ substantially, despite all methods performing similarly well for large ensembles, suggests substantial epistemic uncertainty in estimates of the forced precipitation response in this region.