bluuebunny/crossref_metadata_2025 huggingface dataset:
Understanding the thermal history of the North Aquitaine platform: implications on vertical motion and karstification
Authors: Ortiz Alexandre , Husson Eglantine , Barbarand Jocelyn , Lasseur Eric , Briais Justine
Published: March 2022

The Lower Cretaceous corresponds, in northwestern Europe, to a period of significant extension with the rifting of the Bay of Biscay and its eastern prolongation, the Parentis Basin. This basin has a long history of rifting and several important discontinuities between the uppermost Jurassic and the Albian (at the top of the Jurassic, top of the Barremian and at the Aptian-Albian boundary). North of this basin i.e. the Aquitaine Platform, the sedimentation is very patchy, the few known Lower Cretaceous deposits suggest continental conditions during this period. Preliminary work carried out on some deep boreholes located on the Aquitaine platform reconstructed temperatures by thermochronology (apatite fission track on Triassic and Permian samples). The preliminary results show that these samples are not in equilibrium with the current sedimentary thickness taking into account a conventional geothermal gradient (35°/km). All these the samples then show a significant cooling at the end of the Lower Cretaceous consistent with a regional erosion event. This preliminary work leads us to make two hypothesis:-        The deposition of a Lower Cretaceous sedimentary thickness that was then eroded form the Aptian. This hypothesis is in agreement with study carried out further east (French Massif Central) but not with the first order sedimentary outcropping characterization on the Aquitaine platform.-        The high palaeotemperatures recorded are controlled by an increase in the geothermal gradient (a gradient of 50°/km must be considered) during the Upper Jurassic and Lower Cretaceous. This model does not consider the deposition and the erosion of a thick Cretaceous cover. This hypothesis is difficult to explain over such large area without significant crustal thinning.These two-hypothesis lead to very different palaeogeographical situations and to very different vertical displacement. The answer to these questions is a key in order to understand the periods of karstification of the Jurassic carbonate platform and therefore to have a better knowledge of the water reservoir. We presented in this work the results of an integrated study. The results are based on a combination of field study and the interpretation of subsurface data (boreholes and seismic). A wide range of methods has been applied to this dataset (sedimentology, sequence stratigraphy, well correlation, isotopic and geochemical analysis of carbonate, sand and clay and thermochronology).
Evaluating the effect of DOC on PFAS sorption to soil and colloidal activated carbon using column tests
Authors: Niarchos Georgios , Liebenehm-Axmann Anna Merle , Berggren Kleja Dan , Ahrens Lutz , Fagerlund Fritjof
Published: March 2022

Remediation of sites contaminated with per- and polyfluoroalkyl substances (PFASs) is a significant step towards protecting drinking water sources and limiting human exposure. PFAS production and use is increasingly being restricted worldwide with a reduction of point sources; however, legacy plumes are still posing a threat due to the persistence of these chemicals against degradation. One of the most widely applied soil remediation techniques for PFASs is stabilisation, aiming to long-term entrapment of the contaminants with the addition of fixation agents in the subsurface, which prevent their leaching from soil to groundwater. In relation to this, the aim of this study was to identify the leaching behaviour of various PFASs in a treatment scenario using colloidal activated carbon (CAC). The effect of dissolved organic carbon (DOC), one of the major groundwater constituents in Sweden, on sorption was evaluated. Silt loam soil sampled from central Sweden was used, as well as a mixture of the soil with CAC at 0.1% w/w. Spiked artificial groundwater was prepared with a mixture of 21 PFASs, at a total concentration of 1.4 μg mL-1. The sorption of PFASs to the solid phase was investigated using 15 cm long column experiments under saturated conditions, with and without DOC at 10 mg L-1. Non-reactive tracer tests with NaCl were used to evaluate hydrological parameters. The desorption behaviour after treatment was also investigated, by switching the inflow from contaminated to clean water after steady state was achieved. Analysis of the compounds was conducted using ultra performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). Preliminary results showed retardation of PFASs with the addition of CAC, primarily for long-chain PFASs, exhibiting a correlation between sorption strength capacity and perfluorocarbon chain length. Some short-chain compounds, like perfluorobutanoate (PFBA) and perfluoropentanoate (PFPeA), exhibited immediate breakthrough. Slightly higher retardation of long-chain PFASs was noticed in the presence of DOC, for both treated and reference soil, indicating a potential increase of adsorption sites. Conversely, short-chain PFASs appeared to be outcompeted by DOC and showed faster breakthrough in its presence. These results indicate that humus content can have variable effect on PFAS sorption to soil and CAC, depending on perfluorocarbon chain length. Further experiments aim to the quantification of the sorption capacity.
Knickpoints and faulted alluvial fans: evidence of orogen parallel active extension related to delamination in the Western Betics
Authors: Moreno-Sanchez Marcos , Ballesteros Daniel , Booth-Rea Guillermo , Pérez-Peña José Vicente , Pérez-Mejías Carlos , Reyes-Carmona Cristina , Azañón José Miguel , Galve Jorge P. , Ruano Patricia
Published: March 2022

We present the first results of the MORPHOMED project, in order to deepen the chronology, uplifting rate, and tectonic forcing of different sectors of the Betic Cordillera since the Pliocene. Our initial morphotectonic analysis in the Western Betics, at the active termination of the Betic dextral STEP fault, highlights the location of active orogen-parallel normal faults cutting Pliocene marine sediments, uplifted above 600 masl, and Quaternary alluvial fans. The morphometric study we carried out includes normalized river steepness (ksn) and other geomorphic indices calculated in GIS using our own code designed in python. The fieldwork developed comprises the identification of uplifted Pliocene marine deposits, faulted alluvial fans and remnants of uplifted planation surfaces. The alluvial fans are related to travertine deposits older than 350 ka, which would be associated with hot springs. Geochronological studies involve previous and new U-Th dating on travertines and speleothems from caves in the high areas. The preliminary morphometric analyses reveal the occurrence of knickpoints that coincide with normal faults affecting marine Pliocene deposits and alluvial fans. These fans show vertical displacement of more than 20 m and their age remains unknown albeit the associated travertines are being dated. These results support previous works concerning of active tectonics in the Central and Western Betic Cordillera and they will serve to define new active faults, driving tectonic uplift of the Western Betics, which are the key to understand the landscape evolution forced probably by deep mantle rooted tectonics like slab tearing and edge delamination.
Analysis of hydrogeological behavior of coastal aquifers based on clusters of groundwater hydrograph features and environmental drivers
Authors: Nolte Annika , Haaf Ezra , Heudorfer Benedikt , Bender Steffen , Hartmann Jens
Published: March 2022

Distinguishing between natural and anthropogenic impacts on groundwater systems at regional scale is not straightforward using current data-driven and traditional numerical groundwater models. This limits their benefit for groundwater level predictions and thus future-oriented groundwater resource management. We propose an approach to leverage the large amount of information and variability in the characteristics of groundwater hydrographs and environmental factors to obtain generalized insights into the influences of natural and anthropogenic factors on specific patterns in groundwater hydrographs using data-driven regionalization of groundwater level dynamics. In our approach, we focus on coastal regions that are often under water stress due to the water demands of growing coastal populations building on a data set containing several thousand wells in Europe, North America, South Africa, and Australia.

The approach comprises construction and comparison of multiple unsupervised machine learning cluster models based on a) groundwater level dynamics information, aggregated into groundwater hydrograph features, and b) selected environmental drivers that potentially influence natural groundwater recharge and discharge processes. Environmental descriptors were extracted at well locations from available global map products. We discuss the extent to which our selection of features can express the range of dynamics in representative groundwater hydrographs of clustered basins. Furthermore, we compare the similarity of anthropogenic factors within and between clusters in order to test our hypothesis that hydrograph patterns differ in response to natural processes but irrespective of anthropogenic influences. This would contribute to our understanding of natural processes in coastal groundwater systems.
Snow/rain source mixing and residence time modeling in a sub-alpine mountainous catchment under global warming
Authors: Gupta Aniket , Voisin Didier , Cohard Jean-Martial
Published: March 2022

Mountain catchments behavior is largely governed by snow accumulation and melting regime. These intricate water fluxes sustain the streamflow response for several months and maintain the surface moisture until late summer. The melting snow slowly percolates to the subsurface recharging underground reservoirs which later sustain the ecosystem during the dry periods. During the summer periods in mountainous catchment the rain contributes more to the surface runoff because of steep slopes. In this study, we hypothesise that middle elevation mountain catchments under a warming climate will shift from a snow hydrological recharging behavior to a flash flood behavior. We used ParFLOW-CLM, a fully distributed physical based surface-subsurface coupled integrated hydrological model to show how much water budget partitioning will change on a small subalpine mid-elevation (2000-2200 m) catchment at col du Lautaret (France). With a 10 m hyper-resolution setup, ParFLOW-CLM helps us to distinguish between the Hortonian and Dunian runoff along with the velocity of water movement in the x-y-z direction. Further, we applied a Lagrangian particle tracking model, EcoSLIM, to track the location, movement and residence time of the snow and rain sources. After running the model for the present climate we selected CMIP6 climate model projections that lead to temperature rise from 1 °C to 2.5 °C. The present climate results show that the snowmelt contributes to 90 % of subsurface source particles compared to rain and has a higher residence time in the catchment. These snow particles along with sustaining the streamflow also help in providing water to plants and evapotranspiration during the dry periods. Under warmer climates, the snow to rain ratio decrease leads to more surface runoff and less recharge to the subsurface. The decrease in subsurface recharge leads to reduced surface moisture in the dry season, which directly impacts the evaporation and transpiration through the vegetation. Hence, the rapid global warming leads to a decrease in the snow and subsurface storage which may impact downstream communities in terms of water availability, and at the same time, decrease water availability for the mountain vegetation through reduced surface moisture. In conjunction, the overall mountain ecosystem gets adversely impacted.
Seasonal stress inversion trends and Coulomb stress changes of RTS in Song Tranh2 reservoir, Vietnam
Authors: Nowaczyńska Izabela , Lizurek Grzegorz
Published: March 2022

The Song Tranh 2 hydropower construction is located in the Quang Nam province (central Vietnam), it has a reservoir volume of 740 million cubic meters of water and a dam height of 96 m. The reservoir was filled to capacity for the first time in February 2011. The seismicity in the vicinity of reservoir is example of reservoir triggered seismicity (RTS).  The natural seismic activity of the Song Tranh 2 reservoir is very low. After the reservoir was filled, the seismic activity increased, and the number and frequency of the tremors also changed as the water level changed. Water level changes are accelerating the tectonic process leading the critically stressed faults to slip. Data suggest that reservoir exploitation stress field changes as triggering origin of this seismicity. The stress inversion method was used to check if there were any seasonal trends. The inverted stress tensor and, in particular, the stress ratio, which is very sensitive to data quality and scope and difficult to accurately retrieve, can be influenced by porous pressure changes. Has been checked, how the average annual seismic activity is related to the change of the water level and if it implies the orientation of the principal stress during high and low water levels in the reservoir.  The pore pressure changes and the stress ratio changes were also estimated in relation to the high and low water level periods. Coulomb stress transfer is a seismic-related geological process of stress changes to surrounding material caused by local discrete deformation events.Importantly, Coulomb stress changes have been applied to earthquake-forecasting models that have been used to assess potential hazards related to earthquake activity. It is also often assumed that changes in pore fluid pressure induced by changes in stress are proportional to the normal stress change across the fault plane. Coulomb stress changes was also calculated for low and high water period.
Simulating avalanche problem types to assess avalanche climate zones in the French Alps
Authors: Reuter Benjamin , Hagenmuller Pascal , Eckert Nicolas
Published: March 2022

Snow avalanches result from a complex interaction of weather and terrain, where past weather as well as internal snow cover processes play an important role. Snow cover models account for these processes and simulate the snow cover at a level of detail that allows to describe snow instability. That information on snow instability is required to assess avalanche climates rather than snow climates – which represents a classification based on weather observations. Running the model SURFEX/Crocus with long-term meteorological data (S2M reanalysis) covering the winter seasons between 1958 and 2020, we eventually derived the avalanche problem types for the 23 massifs representing different regions of the French Alps at daily resolution. This allows us to create a climatology based on avalanche problem types and study differences between mountain regions in the French Alps.

In a first step, we applied a commonly used snow climate classification to understand how in the different Alpine regions seasonal characteristics fluctuate under continental or coastal influence. In some regions the majority of the winter seasons had coastal characteristics, whereas in other regions almost half of the seasons were classified continental. In a second step, we add snow instability information by simulating avalanche problem types. This allows us to explore snow instability patterns that result from the meteorological forcing that the snow climate classification summarizes but which the snow climate classification cannot fully capture. Across the regions persistent weak layers and wet snow were the most common avalanche problems types on days when the model expected natural release. Moreover, we applied a k-means clustering to the frequencies of new snow, persistent and wet snow avalanche problem types to identify similarities between in the Alpine regions. We assessed the clustering performance and found that 4 clusters separate well our data which includes information on duration and frequency of avalanche problem types. The clusters coincide with the geographic location of the regions, i.e. Northern, Southern, inner-alpine or front-range regions have specific characteristics that manifest in frequency of avalanche problem types.

We showed how avalanche problem types can be used as an additional descriptor to the snow climate classification to include snow instability specific information. As avalanche problem types identified spatial differences between different snow climate regions, we are now ready to analyze how those changes evolve with time in the different regions.
To what extent our food production depends on anthropogenic phosphorus?
Authors: Demay Josephine , Thomas Nesme , Ringeval Bruno , Pellerin Sylvain
Published: March 2022

Agricultural productivity has dramatically increased in the last sixty years, with undeniable benefits for global food security. Yet, our agricultural production systems have been built on the use of non-renewable resources, thereby altering their sustainability. Agriculture depends on fossil fuel energies – mainly to produce nitrogen fertilizers - but also on another non-renewable resource: phosphate rocks. Here we propose to quantify the reliance of our global food production on the use of fertilizer and additives derived from phosphate rocks, referred to as anthropogenic phosphorus (P). To do so, we simulated the evolution of the soil available P for 132 countries during the 1950-2017 period, with a distinction between both anthropogenic vs. natural soil P stocks. Natural P refers to P that is not derived from mined phosphate rocks. We also explicitly simulated the international trade of feed and food products, given that these fluxes participate in the transfer of anthropogenic P between countries. Finally, for each country, we calculated the P anthropogenic signature of their food production by dividing the anthropogenic P content of agricultural products by their total P content. Our results show that in 2017, the global P anthropogenic signature of food production was ~37%, with large variations across world regions. North America displayed the largest anthropogenic signature (63% ±9% in 2017), followed by Western Europe (55% ±10%), Asia (47% ±7%), Eastern Europe (35% ±10%), South America (33% ±6%), and Africa (20% ±5%). Also, the temporal evolutions of the P anthropogenic signatures reflect the dynamics of agricultural intensification observed in the different world regions. Overall, trade had a negligible effect on the P anthropogenic signature of food production, even when it contributed significantly to increase the soil P fertility of some countries (e.g. The Netherlands). Our estimates of soil P anthropogenic signatures were associated with large uncertainties, raising questions about the best way to estimate soil P legacy and about the data availability to calibrate the models. Eventually, our results highlight the large dependence of global food production to the non-renewable resources that are phosphate rocks. They suggest the urgent need to engage the transition of our food production systems toward more sustainable, input-free and circular agriculture.
Ocean Acidification and Warming effects on important Socio-Economic and Ecological Species in a Sub-Arctic Marine Ecosystem
Authors: Oostdijk Maartje , Sturludóttir Erla , Santos Maria
Published: March 2022

The Arctic is undergoing fast paced changes due to the amplified global change drivers and their effects on biophysical processes there. In particular, ocean acidification (OA) and global warming are likely to affect marine ecosystem processes with severe consequences for livelihoods that depend on natural resources from these ecosystems. Here, we examined those combined effects by running a series of scenarios of OA and warming on an end-to-end ecosystem model (Atlantis) parameterized for the waters around Iceland, and compared those to a baseline projection with no warming and OA. We assessed the resulting population dynamics for a subset of species in Icelandic waters that are important for their economic (catch value), social (number of participants in fisheries), or ecological (keystone species) importance. We used literature-derived values for the sensitivity of these species and functional groups to OA and warming. We show that the responses to OA and warming vary by species and trophic levels; generally, under warming and acidification scenarios several planktonic groups and forage fish improved their populations, while benthic groups and predatory fish populations decreased. When examining the combined effects of OA and warming under current conservative harvest rates for the largest catch-value species, Atlantic cod, we find that surprisingly this population remains stable, even when considering the strongest acidification and warming. However, when the model projects reductions in biomass of Atlantic cod, other species in the ecosystem increase likely due to reductions in competition and predation. Our results highlight possible cascading effects through trophic networks on both ecological and socio-economically important species, and the need for more ecosystem modeling of global change drivers to find such effects.
Degenerate induced magnetospheres
Authors: Barabash Stas , Holmström Mats , Yoshifumi Futaana , Zhang Qi , Ramstad Robin
Published: March 2022

Induced magnetospheres of non-magnetized atmospheric bodies like Mars and Venus are formed by magnetic fields of ionospheric currents induced by the convective electric field E = - V x B/c of the solar wind. When the interplanetary magnetic field is mostly radial (the cone angle θ is close to 0°, quasi-parallel conditions) and the convective field E ≈ 0, an induced magnetosphere becomes degenerate. The degenerate induced magnetospheres can be considered as a specific type of the interaction with ambient plasma. This type of interaction were observed at Venus and Mars, for example, 12 observed cases for Venus and 17 observed cases for Mars for θ < 10° as recorded by Venus Express (2006-2014) and Mars express (2014-2019). However, the quasi-parallel conditions are nominal for the majority of discovered exoplanets (hot Jupiters) orbiting the parent stars on distances 0.01 – 0.1 au when θ < 4° (assuming the solar conditions). The conditions at some moons of icy giants, Neptune (Triton) and Uranus, are also quasi-parallel due to large angle between magnetic dipole and the rotation axis though the plasma flow is subsonic.

In this report we introduce degenerate induced magnetospheres as a new type of interaction and review the current works on the subject. We also show examples of observations at Mars and Venus and numerical simulations, and describe the main properties and basic physics of such configurations.
Identification of large-scale aquifer behavior across three decades of groundwater storage change in the western Mediterranean region
Authors: Chavez Garcia Silva Rafael , Reinecke Robert , Varouchakis Emmanouil , Gómez-Hernández Jaime , Rode Michael , Jomaa Seifeddine
Published: March 2022

The Mediterranean region is undergoing increasing climatic and anthropogenic pressures that challenge water security. Groundwater is a strategic resource for agriculture and water supply in the region, buffering climate change impacts. While previous studies have focused on specific aquifers' water budgets and trends at plot scales, regional dynamics remain unclear. One of the challenges for assessment is the uneven distribution of access to groundwater level monitoring data, as it's not centralized and publicly accessible in most Mediterranean countries. Here we present results that focused on analyzing the groundwater level trends in the countries with the most available groundwater level information: France, Portugal, and Spain. This study contributes to our understanding of groundwater dynamics under varying drivers and groundwater-depletion mitigation options.

As a system with 'memory,' analyzing decades of time series is essential to understand the changes, vulnerability, and resilience. For 1985-1994, 1995-2004, and 2005-2014, a trend analysis was performed on the groundwater levels for piezometers (n=844) covering these periods with considerable completeness. We identified clusters of similar groundwater level developments and categorized them into nine aquifer archetypes, for example: stable water table depth, continued depletion, groundwater level recovery, and local gaining or depleting water levels occurring in each of the three decades. Furthermore, the influence of climate and geological variables on these temporal evolutions were analyzed. Overall, about a third of the studied piezometers showed trends in at least one of the periods. Increasing depths were observed more abundantly in the first period (1985-1994), while decreasing depths were more abundant in the last period.

This work was developed in the scope of the InTheMED project. InTheMED is part of the PRIMA programme supported by the European Union's Horizon 2020 research and innovation programme under grant agreement No 1923.
The short-term effects of enhanced efficiency fertilizers on soil N-cycling genes, and relationship with nitrogen use efficiency in a long-term field experiment
Authors: Zhang Wei , Yang Xuan , Xu Xiuchun , Liu Rui , Meng Fanqiao
Published: March 2022

Enhanced efficiency fertilizers (EEFs) used in agriculture worldwide for mitigating greenhouse gases N2O emissions and improving nitrogen use efficiency (NUE). However, the long-term and instant effects of EEFs on N2O emissions, NUE and the N-cycle related soil functional groups remains elusive. In the current study, we measured N2O emissions, crop yield and plant N content over 4 years (2012-2015) to evaluate the long-term effects of EEFs on N2O emissions and NUE in wheat-maize system in northern China. Besides, we investigated the microbial functional genes (amoA, nxrA, nxrB, narG and nosZ) before and after fertilization to examine how nitrifiers and denitrifiers communities responded to EEFs based on a long-term field experiment. The experiment consisted of the following six treatments: 1) CK, no N fertilizer; 2) U, urea; 3) NI, urea with 3,4-dimethylpyrazole phosphate (DMPP); 4) UI, urea with N-(n-butyl) thiophosphoric triamide (NBPT); 5) NIUI, urea with combined DMPP and NBPT and 6) CRF, urea with controlled release fertilizers. Compared with U treatment, using EEFs reduced cumulative N2O emissions by 30% (UI), 57% (NI), 46% (UINI) and 25%(CRF). The CRF, NIUI, UI and NI treatments increased the annual crop yield (7%, 8%,5% and 5%) and the NUE (44%, 22%, 8%and 9%) relative to the U treatment. Urea and EEFs significantly decreased the diversity of nxrA, nxrB, narG, nosZ rapidly after fertilization, but there was no difference among treatments. Urea applied alone reduced the diversity of AOA-amoA and altered its community structure instantly after fertilization. CRF changed the relative abundance with AOB on Phylum level in short-term, and changed the community composition of AOB after repeated use of CRF. NBPT has a prominent impact on the community structure of narG, whether in the short-term or in the long-term. It can be seen that the effect of EEFs varied according to different functional groups. The long-term and transient effects on soil microbe communities of EEFs might be inconsistent. This indicated that more studies are required focusing on the responds of soil microbe community to EEFs on different time scales.
Greenhouse gas balance of fen meadow landscapes using airborne flux measurements
Authors: Hutjes Ronald , Kruijt Bart , Franssen Wietse , van der Poel Laura
Published: March 2022

Drained organic soils are an important source of greenhouse gases worldwide. Also in the low lying areas of the Netherlands drainage of its organic soils, with the aim to enable more intensive usage of the land, leads to oxidation of organic material, significant carbon dioxide release and subsequent land subsidence. As part of climate mitigation policies the Dutch government seeks to reduce these emissions by about 25% in 2030. In support of these policies, the National Research programme on Greenhouse gas emissions from Fen meadow areas (in Dutch NOBV: https://www.nobveenweiden.nl/) aims to investigate the effects of various mitigation measures on total greenhouse gas balance of the targeted areas.

One approach, complementing multi-site ground based measurements using various techniques, is to use repeated airborne surveys to measure in-situ turbulent CO2 exchange. The push propellor aircraft is a SkyArrow 650 TCNS  equipped with a BAT probe in combination with a Licor 7500 for eddy covariance fluxes of momentum, sensible and latent heat and CO2, augmented by onboard PAR and net radiation sensors. Survey altitude is 200ft/60m nominally, guaranteeing minimal flux divergence between surface and flight level for well-developed boundary layers. Covariances were spatially integrated over 2 km.

In 2020 and 2021 flights were made twice weekly, weather permitting, to cover three major fen meadow landscapes in the Netherlands: the so-called ‘Groene Hart’ area in the west between the cities of Amsterdam, Utrecht and Rotterdam, predominantly used for intensive dairy farming; the ‘Kop van Overijssel’ between Zwolle, Meppel and Vollenhove with large tracts of nature areas besides dairy farming; and finally the South West of the province of Fiesland between Heerenveen, Drachten and Sneek. Flight patterns were designed such that crosswind, parallel flight tracks, separated ~2km, made typical flux footprints overlapping ensuring full spatial coverage of the respective areas.

We will present first analyses and scaling of airborne flux data for each of the three regions in relation to explanatory variables from vegetation and soil characteristics, land and water management (EO and map based) and weather, using machine learning algorithms. Source partitioning based on high frequency airborne covariance data will be used to separate soil and vegetation fluxes. We aim to ultimately provide a data driven regional greenhouse gas balances for the different fen meadow areas of the Netherlands.
Atmospheric acidity and its impacts on macronutrient deposition and plant growth
Authors: Arangio Andrea , Violaki Kalliopi , Quezada Rivera Juan-Carlos , He Megan , Motos Ghislain , Bragazza Luca , Grossiord Charlotte , Buttler Alexandre , Nenes Athanasios
Published: March 2022

Biological diversity and competition among species in ecosystems are sensitive to changes in macronutrient supply and nutrient availability. Human activity is intensively and extensively altering macronutrient cycles from a regional to a global scale with rates that can far exceed natural ones. Moreover, anthropogenic pollution exposes ecosystems to additional nutrients and stressors. These processes, although not well studied, can have a strong impact on ecosystem composition and productivity. In this study, we characterize the atmospheric deposition of bioavailable macronutrients from air pollution and study their impact on plant (oat) productivity and soil quality at a site in the Bois-Chamblard forest outside of Lausanne, Switzerland by Lake Geneva.

To evaluate the importance of atmospheric deposition as a nutrient path for soil and plants, we set up a mesocosm experiment where plants and bare soil were exposed to atmospheric deposition for four months (during Spring and Summer, 2021) and compared against replicates not exposed to atmospheric deposition. Carbon (C), N, P in plant and soil, as well as soil enzymatic activity, fungi and bacterial communities are quantified for each member of the mesocosm experiment. Quantification of the total nitrogen (N) and phosphorous (P), gas- and aerosol-species (inorganic/organic species and metals) in rain water, dry deposition and airborne particles and soil is carried out.

We find that plants exposed to atmospheric deposition display higher photosynthetic activity, larger N content and higher capacity to compete for nutrients in the soil. The soil community in the atmospheric deposition treatment shown higher nitrification rate and enzymatic activity towards lignin decomposition compared to the control. These results indicates that atmospheric pollutants act as plant fertilizers fostering their control on soil microbial community and accelerating soil nutrient stocks consumption.
Sulphide stimulates nitrate reduction in benthic diatoms from a microbial mat 
Authors: Merz Elisa , Dick Gregory J. , de Beer Dirk , Lavik Gaute , Marchant Hannah K. , Klatt Judith M.
Published: March 2022

Diatoms are among the few eukaryotes known to store nitrate (NO3−) and to use it for dissimilatory nitrate/nitrite reduction to ammonium (DNRA) to generate enegry in the absence of light and O2. We used stable isotope incubations and in situ microsensor measurements over complete light cycles to study the diel activity transitions of the NO3−-storing benthic diatom Craticula cuspidata in the submerged Middle Island Sinkhole, Lake Huron (USA). We found that this diatom links NO3− respiration to diel migration into deep (~4 cm) sulfidic sediments below the microbial mat. This pattern was accompanied by pronounced diel changes in the depth of sulphide consumption. During the day sulphide was consumed by anoxygenic photosynthesis and aerobic sulphide oxidation in the uppermost few mm. Surprisingly, the consumption zone moved downward in the evening and was deepest in the sediment at night. Thus, the sulphide consumption zone strikingly overlapped with the depth of DNRA-performing diatom residence. Using an enrichment of Craticula cuspidata, we found that the nitrate respiration via DNRA was ~10-fold higher in the presence of sulphide. Overall, our data therefore indicate that C. cuspidata and/or their microbiome link NO3− reduction to sulphide oxidation.
Stress field observations from hydraulic fracturing and focal mechanism inversion at the STIMTEC underground research lab, Reiche Zeche mine, Germany
Authors: Boese Carolin , Kwiatek Grzegorz , Renner Joerg , Dresen Georg
Published: March 2022

Between 2018 and 2021, the STIMTEC and STIMTEC-X hydraulic stimulation experiments were conducted at 130 m depth in the Reiche Zeche underground research laboratory in Freiberg/Germany. The STIMTEC experiment was designed to investigate the rock damage resulting from hydraulic stimulation and to link seismic activity and enhancement of hydraulic properties in anisotropic metamorphic gneiss. The following STIMTEC-X experiment aimed at better constraining the stress field in the rock volume to investigate the mechanisms leading to induced acoustic emission (AE) activity. Here, we present results from focal mechanism analysis of high-frequency (>1 kHz) AE events, associated with brittle deformation at the cm- to dm-scale induced by hydraulic stimulations. Focal mechanisms are calculated using full moment tensor inversion of first P-wave amplitudes using the hybridMT package. We use polarity and amplitude data from a (near) real-time seismic monitoring network, consisting of AE sensors, AE-hydrophones, accelerometers, and one broadband sensor. We observe changes in the predominant type of faulting from reverse faulting focal mechanisms during the frac and refrac cycles to oblique strike-slip focal mechanisms observed during subsequent high-volume fluid-injections performed during periodic pumping test. The observed differences in dominant focal mechanisms are consistent with the activation of less favourably oriented faults at increased pore fluid pressure during extended periodic pumping. We observe a reverse-faulting stress regime from focal mechanism inversion of low-volume injection stages for different boreholes, representative for the rock volume (typically ~5 m radially) surrounding the injection intervals. In contrast, stress field estimates obtained from analysing the instantaneous shut-in pressures of hydraulic stimulations in different boreholes indicate a regime change from thrust to strike-slip faulting in the investigated rock volume. The reservoir complexity seen at the scale of the experiment (30m x 30m x 20m) is large and is reflected by the significant variations in AE event activity in response to stimulation as well as small-scale rock, stress and structural heterogeneities.
Bioturbation-driven transport of microplastic fibres in soil
Authors: Heinze Wiebke Mareile , Mitrano Denise M. , Cornelis Geert
Published: March 2022

Microplastic pollution of the terrestrial environment and its potential impact on ecosystem services are gaining increasing public and scientific attention. Although the number of investigations on microplastic presence in soil under different management systems is growing, knowledge on the potential mobility of microplastics and their spatial distribution within soil is still lacking. In particular, microplastic fibres are often considered less mobile in soil due to their elongated shape and the resulting potential entanglement in pore structures or aggregated soil particles. While these processes may affect their water-driven transport, biologically-driven transport may still occur unimpeded because particles may be ingested by macrofauna such as earthworms. Micro- and nanoplastic transport by earthworms has been previously observed, however, the effect of particle shape on the transport dynamics is still elusive.

For understanding microplastic fibre transport in soil from a mechanistic perspective, we performed a series of process-studies with deep-burrowing earthworms, i.e. Lumbricus terrestris, in microcosms. We utilized metal-doped fibrous polyethylene terephthalate (PET) microplastics (1.27±0.66 mm) for a facilitated detection through acid extraction and subsequent analysis via inductively-coupled plasma mass-spectrometry. Fibres were spiked into the top of the soil columns of the microcosms, which were sampled according to specific depth segments every 7 days for four weeks. As a result, we were able to quantify fibre transport in soil profiles with a temporal resolution. Earthworms were important drivers of vertical transport of microplastic fibres in the soil, with fibres visibly incorporated into burrow walls. Thus, despite their elongated shape and relative larger size, microplastic fibres are not necessarily immobilized by interactions with soil particles, but continuously affected by burrowing soil organisms. Understanding these transport dynamics and the potential spatial distribution of microplastics of different shapes and sizes in the field is crucial in order to support appropriate sampling schemes for monitoring and for obtaining accurate mass estimates of microplastic pollution of terrestrial ecosystems.
Total ozone loss during the 2021/22 Arctic winter and comparison to previous years
Authors: Pazmino Andrea , Goutail Florence , Pommereau Jean-Pierre , Lefèvre Franck , Godin-Beekmann Sophie , Hauchecorne Alain , Lecouffe Audrey , Chipperfield Martyn , Feng Wuhu , Van Roozendael Michel , Jepsen Nis , Hansen Georg , Kivi Rigel , Alwarda Ramina , Strong Kimberly , Walker Kaley
Published: March 2022

The amplitude and rate of ozone depletion in the Arctic is monitored every year since 1994 by comparison between SAOZ UV-Vis ground-based network from NDACC and Multi-Sensor Reanalysis 2 (MSR-2) total ozone measurements over 8 stations in the Arctic and 3-D chemical transport model simulations in which ozone is considered as a passive tracer. The passive ozone method allows determining the cumulative loss at the end of the winter. The amplitude of the destruction varies between 0-10% in relatively warm and short vortex duration years to 25-38% in colder and longer ones, which the record winters estimated in 2010/2011 and 2019/2020.

In this study, the interannual variability of 10-days average rate of 2021/2022 winter will be analyzed and compared to previous years. In addition, SAOZ NO2 data will be used to evaluate re-noxification in the Arctic. The long-term ozone loss series estimated from measurements will be compared to REPROBUS and SLIMCAT CTM simulations. Relationship with illuminated Polar Stratospheric Clouds will be also presented.
The Anthropocene Geoarchaeology of the Yellow River  
Authors: Storozum Michael
Published: March 2022

China’s Yellow River, which gains its name from the extraordinary amount of yellow-brown silt it entrains, was not always so yellow. Current historical and geological evidence suggest that the Yellow River experienced several periods of human-induced transformation that have not only changed the color of the Yellow River’s water, but also fundamentally altered the river’s hydrological properties, specifically by increasing the Yellow River’s propensity for catastrophic floods. In this paper, I argue that the long history of soil erosion and Yellow River floods is a defining characteristic of China’s incipient Anthropocene period and can be understood through the application of geoarchaeological methods and frameworks. Specifically, I focus on how extreme Yellow River flood events at Kaifeng, a former capital of dynastic China, have shaped the city’s urban resilience in the wake of a flood that killed over 300,000 people in AD 1642. Recent geoarchaeological excavations have discovered evidence that reveals the AD 1642 Yellow River flood destroyed Kaifeng’s inner city, entombing the city and its inhabitants within meters of silt and clay. I argue that the geology of the Yellow River floods and the socio-political context of Kaifeng shaped the city’s resilience to extreme flood events. Through this example, the long-term consequences of China’s early Anthropocene are brought out in sharp relief. Flood events like at Kaifeng not only represent significant hydrological shifts in the Yellow River, but also had dramatic social consequences as numerous Yellow River floods have coincided with the collapse major Chinese dynasties. In conclusion, I suggest that a deeper understanding of the origins and long-term development of the Yellow River as a coupled human and natural system is fundamental to designing more sustainable solutions to managing the Yellow River and other large, muddy, rivers around the world.
How do changes in model parameters compare to climate change impacts signals? A case study of a modeling chain to predict reservoir inflow and sedimentation processes in the Devoll Catchment (Albania)
Authors: Pesci María Herminia , Mouris Kilian , Bosshard Thomas , Förster Kristian
Published: March 2022

Mountainous regions are viewed as “water towers”, where lower temperatures and higher precipitations affect the annual water balance with snow accumulation in winter and maximum runoff driven by snowmelt during spring or summer. Moreover, the need for effective water resources management has turned into a major challenge, especially in the face of climate change. The current development of computer models allows representing the response of catchments even under the impact of changing climate conditions. For this reason, the Devoll catchment in Albania, which is characterized by a Mediterranean climate and varying topography, is studied as part of a modelling chain up to the Banja reservoir, where sedimentation processes are of great importance.
Three different models are used to predict the response of the catchment within the modeling chain: i) a hydrological model (WaSiM), ii) a soil erosion and transport model (RUSLE and SEDD), and iii) a three-dimensional numerical model (SSIIM 2) to simulate flow and suspended sediment transport in the reservoir. Since numerous parameters are involved in the chain and those can introduce uncertainties in the subsequent models, an approximate method is applied to estimate the uncertainties arising from the model parameters, whereby each parameter is subject to a ±1% variation. In addition, climate change impacts are considered while running the modeling chain with different climate scenarios. In all cases, we focus not only on discharge as a target variable but also on the suspended sediment load and bed elevation along the reservoir transect. Finally, a comparison between the results obtained from the variation in parameters and climate change impacts is performed.
Temperature affects the frictional stability of experimental clay-bearing fault gouges
Authors: Ashman Isabel , Faulkner Daniel
Published: March 2022

Field observations have shown that mature fault zones are rich in clay minerals (e.g. MTL in Japan, Punchbowl Fault in USA, and Alpine Fault Zone in New Zealand). Most mature fault zones are also seismogenic, which is at odds with the velocity strengthening behaviour observed for clay-bearing material in rock deformation experiments. The measurements of rate and state friction in clay-bearing material show that most clay-bearing material would favour aseismic creep when the experiments are conducted at room temperature. To address this disparity between experimental and field observations, a set of controlled friction experiments were devised to investigate the effect of varying temperature conditions on the frictional properties of clay-bearing fault gouges.
The velocity-step friction experiments were conducted in a triaxial deformation apparatus at an effective normal stress of 90MPa and ambient temperatures that increased from room temperature (23°C) to 180°C in increments of 40°C. In order to measure the rate and state frictional properties of the fault gouges, the imposed slip velocity was stepped between 0.3-3 μm/s. The simulated quartz-clay fault gouges had controlled clay (kaolinite) contents in increments of 25wt% from 0-100wt%. Preliminary results show that by increasing the ambient temperature during fault slip, the rate and state friction parameter [a–b] consistently decreases significantly in clay-bearing fault gouges, often from a velocity strengthening [a–b] value to a weakening [a–b] value. This is consistent with the previous, limited studies of clay-bearing material at elevated temperatures. In the clay-poor gouges, the velocity weakening [a–b] parameter is accompanied by dynamic stick-slip behaviour, whereas in clay-rich gouges the velocity weakening [a–b] parameter shows initially unstable slip that is dampened and arrests to aseismic slip. The elevated temperatures in fault zones at depths up to ~6km, as investigated in this study, can therefore lead to unstable fault slip in clay-rich material that is velocity strengthening at room temperature. It is proposed that elevated temperatures are an important component of seismogenic slip occurring in clay-rich material, as is observed in natural faults.