bluuebunny/crossref_metadata_2025 huggingface dataset:
The origin of tectonic mélanges and implication for the subduction interface processes
Authors: Rajič Kristijan , Raimbourg Hugues , Famin Vincent , Moris-Muttoni Benjamin
Published: March 2024

Tectonic mélanges, penetrative mixes of sediments and basalts, are often interpreted as fossil subduction plate interfaces. These formations, marked by intense deformation, contain witnesses of past earthquakes and commonly include remnants of the oceanic crust of the subducting plate. The original process that led to penetrative mixing of sediments and basalts is often controversial, and classically relies either on tectonic slicing of the downgoing plateduring subduction, or on pre-subduction, olistostrome-forming sedimentary mixing. In addition, magma emplacement in sediments of the downgoing plate may also explain the mixed lithologies of mélanges. This latter case should leave an aureole of contact metamorphism in sediments near basalts. In this work, we applied Raman Spectroscopy of Carbonaceous Material in the modern seafloor sediments where magmatism is reported, in order to evaluate the thermal influence from basalts onto carbonaceous material in the contacting sediments. Then, to check the potential contact metamorphism in mélanges, we employed the same methodology in several examples of sediment-basalt mélanges at (sub)-greenschist-facies conditions (Kodiak complex, Alaska; Shimanto Belt, Japan).In modern ocean-floor settings, magmas intruding, and to a lesser extent, flowing onto sediments, resulted in higher crystallinity of carbonaceous material in a cm- to dm-thick contact aureole. In four of five studied mélanges, the crystallinity of carbonaceous material in metasediments increases toward basalts, indicating a ~1 cm-thick contact metamorphism aureole. Thus, we propose that for the studied mélanges the mixing likely occurred prior to subduction, with the preservation of contact metamorphism despite syn-subduction, low-temperature metamorphism.As a consequence, the block-in-matrix structure observed in mélanges, as well as the occurrence of mafic bodies at seismogenic depths in accretionary prisms, is in many instances the result of pre-subduction structure, rather than tectonic slicing and step-down of the decollement into the oceanic crust. In particular, tectonic mélanges such as Mugi in Japan and Ghost Rocks in Alaska do not reflect simply the structure and thickness of the plate subduction interface, but a complex combination of pre-subduction geometry and tectonic processes during underplating and within the accretionary wedge.Furthermore, in two studied paleo-accretionary complexes, deposition ages of the trench sediments forming the matrix of three examined mélanges overlap ages of magmatism within uncertainty. Considering that the basalts from these mélanges exhibit MORB signatures, this age overlap suggests that the mélanges possibly formed at the trench just before ridge subduction. We thus conclude that basalt-sediment mélanges stand as potential records documenting ancient ridge subduction events.
Seismic and core-based glacial sequence stratigraphy of an overdeepened valley fill in northern Switzerland 
Authors: Schaller Sebastian , Schuster Bennet , Beraus Sarah , Buechi Marius W. , Buness Hermann , Anselmetti Flavio S.
Published: March 2024

In the context of the DOVE (Drilling Overdeepened Alpine Valleys) project, supported by the International Continental Scientific Drilling Program (ICDP), a series of boreholes were drilled into buried overdeepened glacial troughs situated in the northern forelands of the Central and Eastern Alps. The sediments infilled into these troughs provide relatively complete sedimentary records of the Mid- and Late Pleistocene and help to better understand past glaciations, paleoclimate, and landscape evolution. As part of this project, an over 250 meters thick succession of unconsolidated Quaternary lacustrine and glacio-to-glaciofluvial sediments was successfully cored from the Basadingen Trough (ICDP 5068_2, NE Switzerland). This overdeepend trough is located in the NE sector of the former Rhine glacier's foreland lobe and is associated with an SSE-NNW valley system that connects the present-day Thur Valley with the Rhine Valley. This association, absent in the current surface morphology, is believed to have been active solely during the Middle Pleistocene.The correlation of the core with two lines of high-resolution 2D seismic data (acquired during a pre-drill site survey) directly links seismic facies, the petrophysical data of the core (obtained from MSCL- and wireline-logging), and sedimentological properties. This link allowed us to develop a glacial sequence stratigraphy, based on which the overdeepend valley fill could be grouped into three glacial sequences (S1 – S3), enabling a more detailed reconstruction of the glacial advance and retreat history.Furthermore, integration of the 2D seismic lines with the local geological information (e.g., drill cores, bedrock map, topography, model of the Quaternary sediment cover) has facilitated the establishment of a three-dimensional model of a segment of the Basadingen Trough. This model visualizes the shape of the initial bedrock incision, the multiphase trough-infill architecture, and the emplacement of fluvial channels overlaying the overdeepend basin. This three-dimensional approach overcomes inherent limitations in two-dimensional representations, providing a more accurate mapping of actual geometries. This study thus contributes to the development of a local glaciation model for the Basadingen Trough and a model of subglacial erosion of overdeepened basins in the northern Alpine foreland.
High pressure diversity of solid organic compounds in subduction zones, a window to the deep organic carbon cycle.
Authors: Debret Baptiste , Ménez Bénédicte , Caurant Clara
Published: March 2024

The nature and the fraction of carbon that are recycled to the deep Earth via the subduction factory remain an active and controversial research frontier. While many studies have attempt to establish the budgets and distribution of inorganic carbon in the subducting slab at high pressure (HP), relatively little is known about the organic counterpart. Here, we explore the nature and diversity of solid organic compounds trapped in HP ultramafic rocks from the Monviso meta-ophiolite. We show that the eclogitic ultramafic rocks record strong variations of redox conditions (i.e., oxygen fugacity, fO2) during subduction. Such variations influenced carbon distribution and redox state. In particular, reducing conditions associated with brucite breakdown in meta-ophicarbonate promoted the formation of an unexpected diversity of abiotic carbon-based materials, ranging from disordered carbonaceous matter and organic minerals, never described in HP environments, to nanodiamonds. These newly-formed organic compounds could subsequently be recycled in the deep mantle, with the potential to play a major role on the deep carbon cycle, therefore calling for a thorough examination of the diversity, abundance and stability of solid organic phases under deep Earth.
EMAN7: understanding methane seepage dynamics in the Hola Trough
Authors: Ferré Bénédicte , Barreyre Thibaut , Bünz stefan , Argentino Claudio , Corrales-Guerrero Jorge , Dølven Knut Ola , Stetzler Marie , Fallati Luca , Sert Muhamed Fatih , Panieri Giuliana , Rastrick Samuel , Kutti Tina , Moser Manuel
Published: March 2024

The Hola Trough, offshore Norway’s Lofoten-Vesterålen (LoVe) area, has been of interest for many years due to its rich marine life and potential oil and gas resources. There, coral mounds thrive around methane seepage. The LoVe observatory network monitors this unique environment. Using this observatory platform, associated dataset and research expeditions at sea, the project EMAN7 (Environmental impact of Methane seepage and sub-seabed characterization at LoVe-Node 7) aims to understand the environmental impact of methane seepage as well as its spatio-temporal variability.The comparison of methane seep activity during two summers with different environmental conditions revealed 3.5 times more seeps when a combination of warmer bottom water and low tide changes the sediment pore pressure. Piezometer data, recording subseafloor pore pressure and bottom temperature, support these findings. Sub-seafloor investigations identified pathways for gas migration in methane seep areas, influenced by topography.This study is supported by the Research Council of Norway, project number 320100, through the project EMAN7.
Anticipating future extreme wildfire events by coupling ignition and success of initial attack models
Authors: Gelabert Vadillo Pere Joan , Jiménez Ruano Adrian , Catelo Fellice , Rodrigues Mimbrero Marcos
Published: March 2024

In recent years, the EU Commission has enacted various firefighting policies to combat and diminish the adverse effects of wildfires. The Mediterranean area has experienced an observable extension of its wildfire season, coupled with rapid shifts in fire-weather dynamics, resulting in exceptionally severe wildfire occurrences. As of 2022, the EU has recorded an approximate total burned area of 792,902 hectares, with forests accounting for 66% of this figure (Rodrigues et al., 2023).The main objective of this study is to anticipate extreme wildfire conditions by providing a synthetic product depicting the chances of a fire event starting and escaping containment. To do so, we combined empirical models of ignition likelihood and effectiveness of the initial attack stage. We employed machine learning techniques to calibrate binary regression models using historical wildfire ignition data and geospatial layer depicting the main drivers of ignition and containment, namely: accessibility, human pressure on wildlands, fuel moisture and availability. We illustrate our approach along the Mediterranean coastal region of Spain. Our approach enables us to predict wildfire contention capacity under diverse population growth and climate warming scenarios. This strategy aims to improve disaster risk reduction by pointing wildfire management zones and prioritizing intervention in high-risk areas.Results indicate a high predictive ability to model human-caused wildfire ignition (AUC>0.80) but a modest capability to capture the containment capability (AUC≈0.70). Accessibility by road largely controls the spatial pattern of ignition and containment, with dead fuel moisture content modulating the temporal pattern of probability. We further illustrate the approach by providing insights into future SSP (Shared Socieconomic Pathways) scenarios by synthesizing both products into comprehensive management zones (Rodrigues et al., 2022). ReferencesRodrigues, M., Camprubí, À.C., Balaguer-Romano, R., Megía, C.J.C., Castañares, F., Ruffault, J., Fernandes, P.M., Dios, V.R. de, 2023. Drivers and implications of the extreme 2022 wildfire season in Southwest Europe. Science of The Total Environment 859, 160320. https://doi.org/10.1016/j.scitotenv.2022.160320Rodrigues, M., Zúñiga-Antón, M., Alcasena, F., Gelabert, P., Vega-Garcia, C., 2022. Integrating geospatial wildfire models to delineate landscape management zones and inform decision-making in Mediterranean areas. Safety Science 147, 105616. https://doi.org/10.1016/j.ssci.2021.105
Improving the prediction of East Asia summer monsoon precipitation using a Bayesian dynamic linear model
Authors: Xing Wen , Han Weiqing , Zhang Lei
Published: March 2024

Seasonal prediction of East Asia summer monsoon rainfall (EASMR) is in great demand but remains challenging, because the relationships between the Asian monsoon system and precursors are nonstationary and exhibit significant decadal changes. The present study aims to 1) examine decadal variations of the relationships between the EASMR and predictors used in previous studies and 2) establish a new prediction model using a Bayesian dynamical linear model (DLM), which is capable of capturing the time-evolving relationships between the predictand and predictors whereas the conventional static linear model cannot.Two predictors were selected previously to predict the EASMR. One is the sea level pressure tendency anomalies over the tropical eastern Pacific from late spring to early summer, which represents remote forcing related to ENSO and has a stable effect on EASMR throughout the analysis period. The other is the sea surface temperature anomaly difference between the northern Indian Ocean (IO) and the WNP during spring through early summer (called IOWPSST), which denotes local air-sea interaction that affects the WNP subtropical high. Results show that the IOWPSST has strong influence on EASMR during 1979 to 2003 (period 1), while from 2004-2017 (period 2) its connection to EASMR evidently weakens. This nonstationary relationship is due to the non-persistence of the enhanced WNP subtropical high during period 2, which is associated with the positive-to-negative phase transition of the Interdecadal Pacific Oscillation since ~2000.A new prediction model was established using the two predictors with Bayesian DLM. The cross-validation method and a 9-yr independent forward-rolling forecast is applied to test the hindcast and actual forecast ability. Results show that the Bayesian DLM has higher hindcast/forecast skill and lower mean square error compared with static linear model, suggesting that the DLM has advantage in predicting EASMR and is a promising method for seasonal prediction.
Influence of the solar cycle and stratospheric intrusions to the tritium variation of continental ice layers (Colle Gnifetti, European Alps and EGRIP camp, Greenland)
Authors: Palcsu László , László Elemér , Veres Mihály , Surányi Gergely , Vargas Danny , Temovski Marjan
Published: March 2024

Examining continental ice layers accumulated before the nuclear era, when the artificial tritium component can be excluded, enables us to better understand the natural variation of cosmogenic tritium (3H). The extremely sensitive 3He-ingrowth method of 3H analysis allows us to determine low level tritium activities with high accuracy. Here we provide a detailed tritium profile of two shallow ice cores drilled in the European Alps and Greenland.A sensitive tritium profile of the top 33.7 m of the ice accumulation at Colle Gnifetti (Swiss-Italian Alps) is provided. The tritium concentrations of annual ice layers before 1953 vary between 0.050 and 0.145 TU with uncertainties of 0.0019 to 0.0048 TU. The tritium values reconstructed for the time of accumulation are varying between 4 and 10 TU. The long-term pattern of tritium in the ice (mainly before 1940) is in anti-correlation with the sunspot numbers. As the ice is not contaminated with artificial tritium, this change can be strongly attributed to the 11-year cycle of solar magnetic activity. This confirms the existing link between the Solar cycle and the cosmogenic tritium of precipitation [1].On the contrary, in Greenland at the EGRIP camp, the signal of the solar cycle is hardly visible. The natural level of tritium at around 20 TU is disturbed by large spikes (>400 TU). These spikes seem to be randomly distributed in time. There are annual layers which are unaffected. The reason of the high tritium concentration might be the stratospheric moisture input as shown by Fourré et al. (2018) [2]. Stratospheric moisture can be also identified by its 17O-excess pattern. Here we provide the correlation of tritium and 17O, as a hint of the origin of excess tritium. On the other hand, the evaluation of the first results shows that the strength of the stratospheric intrusions qualified by tritium amount seems to be weakening over the last 100 years.[1] Palcsu, L., Morgenstern, U., Sültenfuss, J., Koltai, G., László, E., Temovski, M., Major, Z., Nagy, J.T., Papp, L., Varlam, C., Faurescu, I., Túri, M., Rinyu, L., Czuppon, G., Bottyán, E., Jull, A.J.T. Modulation of Cosmogenic Tritium in Meteoric Precipitation by the 11-year Cycle of Solar Magnetic Field Activity, Scientific Reports 8 (2018) 12813.[2] Fourré, E., Landais, A., Cauquoin, A., Jean-Baptiste, P., Lipenkov, V., Petit J.-R. Tritium Records to Trace Stratospheric Moisture Inputs in Antarctica. Journal of Geophysical Research: Atmospheres 123 (2018), 3009-3018.
A multi-resolution deep-learning surrogate framework for global hydrological models
Authors: Droppers Bram , Bierkens Marc , Wanders Niko
Published: March 2024

Global hydrological models (GHMs) are an important tool for sustainable development making in today’s water-scarce world. These models enable assessment of water scarcity by estimating both the natural water cycle and human activities around the world. Moreover, their process-based structure allows for projections under diverse climate change and socio-economic scenarios; information that is essential to support sustainable water management. Nevertheless, the need for better, higher resolution and larger ensemble simulations is reaching the limit of what is computationally feasible.Recently, the deep-learning community has shown the potential of neural networks in providing highly accurate and computationally cheap hydrological predictions. This development has let to the emergence of deep-learning model surrogates that mimic process-based hydrological simulations using neural networks. Yet, the majority of these surrogates are restricted to assessing land-surface water fluxes at a singular spatial resolution, thereby limiting their application for global hydrological models.We present a novel framework to create deep-learning global hydrological surrogates, with two salient features. First, our surrogate framework integrates spatially-distributed runoff routing that is essential to estimate water availability and human water withdrawals. Second, our surrogate framework offers scalability across various spatial resolutions and can match the wide variety of resolutions at which global hydrological models are applied.To test our framework, we developed a deep-learning surrogate of the PCRaster Global Water Balance (PCR-GLOBWB) global hydrological model. The surrogate encompasses all water-balance components, including the impact of human activities on the water system. The PCR-GLOBWB surrogate runs faster than its process-based counterpart and performs well when compared to the original model’s output at different spatial resolutions. Interestingly, the multi-resolution surrogate actually outperforms model surrogates trained for a single resolution, even on their target resolution.Deep-learning surrogates are a useful tool for the global hydrological modeling community, enabling enhanced model calibration (through parameter learning and flux matching) and more detailed model simulations. Our framework provides an excellent foundation for the community to create their own multi-scale deep-learning model surrogates.
Musical messages – Creating a Bespoke Climate Story for the Outer Hebrides
Authors: Pope James , Logan Matthew , Kennedy Sandra , MacDonald Kathleen , Matthews Alicia , Milne Kathleen , Pratt Eleanor
Published: March 2024

Exposed to westerly and south-westerly Atlantic weather systems, the Outer Hebrides (off the west coast of Scotland) are a series of islands where the inhabitants are already well versed in coping with severe weather.  Headed by the Outer Hebrides Community Planning Partnership (OHCCP) Climate Change Working Group (CCWG), a range of adaptation planning documents are in production. Driven by a desire to engage with local communities, the CCWG alongside the Làn Thìde Climate Beacon, Adaptation Scotland and the Met Office created a project to explore the development of a storyline to communicate climate change information to the Outer Hebrides community.  Collaborating with a local artist, Tuil is Geil (Gaelic for “Flood and Wind”) was created through a combination of sonified climate data, local voices and field recordings of local weather.  Three themed pieces were created and these pieces (alongside a science presentation on projections of climate change for the Outer Hebrides) formed the centre of public engagement sessions when members of the public were able to share their thoughts about vulnerabilities and adaptation needs on the islands. As a project team we learned a number of important lessons around the process for creating a bespoke storyline for a community which included: i) The need to set appropriate boundaries and manage expectations, ii) The importance of local partner organisations and networks, iii) The need to bridge between science and art, and iv) The need to collaborate with the local community. We strongly believe that this approach has major community impact and it is the intention to support similar storyline projects in other regions of Scotland.
Development and validation of an automated method using a FlowCAM to detect and quantify Spheroidal carbonaceous particles (SCPs) from peat samples
Authors: Liu Rongqin , Le Roux Gaël , Gandois Laure , Rose Neil , Azemar Frederic , Hagelskjaer Oskar
Published: March 2024

The semi-quantitative exploration of Spheroidal Carbonaceous Particles (SCPs) and pollen determination in sediments has opened new avenues for studying historical atmospheric contamination trends. These particles can be found in lake, peat, ice, and other geologic archives, and have been proposed as a marker to serve as the Global Boundary Stratotype Section and Point (GSSP) for the onset of the Anthropocene in the geologic time scale, offering globally synchronous indicators of human impact. SCPs generated by high-Temperature processes, have no natural source compared to traditional methods like radiocarbon dating and lead isotope analysis, fly-ash particles present a cheaper and more accessible alternative as a simple chronomarker.
Our study focuses on SCPs using FlowCAM (Fluid Imaging Technologies, FC) as an alternative tool to identify and quantitatively enumerate these particles in peat samples from purely ombrotrophic Sphagnum bogs. To investigate SCPs in peat samples, the study aims to develop a semi-automated analytical method using SCPs reference materials to create an "SCPs library" as a filter to investigate the concentration and distribution of SCPs in the Pyrenees. The research evaluates the effectiveness of FlowCAM in quantifying SCPs and demonstrates its potential as an independent method for studying historical atmospheric contamination trends in natural peat samples. FlowCAM was used to quantify SCPs from a reference material with an accuracy of 105% and a standard deviation (SD) of 34%. SCP profiles could be established in natural peat cores and allowed the reconstruction of the history of anthropogenic deposition in the Pyrenees and remote regions. All the characteristic data of SCPs from FlowCAM could also be a tool for analysis with other natural samples; this "SCPs library" could be continuously strengthened with more sample measurements to accurately refine the results from FlowCAM and inform atmospheric models based on retro-observations.
The response of phytoplankton community to dissolved organic matter composition and lake trophic state: Insights from the largest urban lake in China
Authors: Ai Yadi , Cheng Hongguang , Gong Yiwei , Quan Weici , Yang Kaiming
Published: March 2024

The dual impacts of human activities and climate change have increased the input of dissolved organic matters (DOM) into urban lakes, which is crucial for aquatic biogeochemical cycle and global carbon cycle, affecting the lake ecological health to some extent. What's more, phytoplankton are sensitive to changes in water environment, making them important indicator organisms in water environment monitoring. However, the composition dynamics of phytoplankton community and DOM in shallow urban lakes under strong anthropogenic disturbances, and their relationship remain poorly understood. Thus, this study aimed to reveal the composition dynamics of phytoplankton community and DOM in urban lakes, identify the main environmental factors affecting phytoplankton communities, and understand the relationship between DOM and phytoplankton composition in various trophic states. A whole-year campaign was conducted in Tangxun Lake, Wuhan City, the largest urban lake in China, which is highly urbanized and industrialized. The parallel factor analysis method (PARAFAC) was applied to identify the three-dimensional fluorescence spectra and components of DOM. As a result, it was found that: The water quality of Tangxun Lake exhibited strong spatiotemporal variability, mainly presenting a state of eutrophication to moderate eutrophication. A total of 54 genera, 26 families, 15 orders, 9 classes, 6 phyla of phytoplankton have been identified in Tangxun Lake. The phytoplankton community structure was diatomic-green algae-cyanobacteria type as a whole, and the seasonal succession changes of phytoplankton community were significant. Excitation–emission matrix fluorescence spectroscopy (EEMs) coupled with PARAFAC indicated that DOM in Tangxun Lake consisted of four components, mainly terrestrial component. This study reveals the response of phytoplankton to DOM and lake trophic status, which has profound implications for the aquatic ecosystem management, and provide reference for the potential correlation mechanism among lake carbon cycle, CDOM source composition and phytoplankton community.
Seismic ground shaking by historical earthquakes in the Firenze metropolitan area
Authors: Ayoqi Najmeh , Marchetti Emanuele
Published: March 2024

The seismic vulnerability assessment of a complex metropolitan area depends on the seismic source, wave propagation, and site amplification, as well as seismic response of single edifices. As a first step to evaluate the seismic vulnerability of Firenze, we computed the seismic ground motion on rigid bedrock of the 1919, 6.3 Mw Mugello earthquake in Tuscany, Italy, through a stochastic finite-fault technique (EXSIM) in conjunction with the Python framework.The theoretical shake maps, evaluated at epicentral distances ranging between 10 and 100 km, is computed from 360 synthetic waveforms and corresponding Fourier acceleration spectrum, pseudo-spectral acceleration, peak ground acceleration, and peak ground velocity in the high-frequency range (f > 1 Hz). Synthetic waveform analysis is performed to investigate the model dependance on the various input parameters and corresponding confidence levels.Comparison between model results and shake maps obtained from historical damages was used to validate the analysis and discuss the relation between expected damages and the main seismogenic area around the city. This study is performed in the framework of the HGP project (CUP:B55F21007810001) funded within the Next Generation EU program.
Optimizing UAV seaweed mapping through algorithm comparison across RGB, multispectral, and combined datasets
Authors: akhmetshin damir , Naughton Owen , Cavanagh Leon , Callaghan Dean
Published: March 2024

The use of unmanned aerial vehicles (UAVs) with off-the-shelf RGB and multispectral sensors has expanded for environmental monitoring. While multispectral data enables analysis impossible with RGB, visible range cameras have benefits for large-scale habitat mapping. This research compared RGB, multispectral, and fused RGB-multispectral data from UAVs for seaweed mapping along the Irish coast. Three classification algorithms – Random Forest, Maximum Likelihood Classifier and Support Vector Machines – were tested on the three datasets to compare accuracies for seaweed species delineation and percent cover estimation. The RGB sensor effectively classified broad intertidal classes, but struggled differentiating some seaweed species. Multispectral data significantly improved species-level classification accuracy but tended to overestimate the presence of red and green algae. Fusing the RGB and multispectral data improved species classification accuracy over multispectral and RGB images. The results demonstrate the benefits of RGB sensors for broad habitat mapping and cover estimation, and multispectral for detailed species delineation. Fusion of the two sensor types enhances the strengths of both. This highlights the potential for UAVs paired with off-the-shelf visible range and multispectral cameras to provide detailed, accurate, and affordable change monitoring of intertidal seaweed habitats.
Glucose Release Controlled by Sugar Transporters in Wheat Plant Modulates Microbial Growth and Enzyme Activity Around the Root
Authors: Rashtbari Mehdi , Hosseini Seyed Sajjad , Azimi Ahmad Samir , Schemmel Markus , Zhou Zheng , Han Lingyue , Cai Daguang , Razavi Bahar S.
Published: March 2024

Soil microbial communities are the main regulators of ecosystem services and are vital for carbon and nutrient cycling. Root exudates play a crucial role in shaping soil microbial assembly and hence, influencing biogeochemical processes that impact plant growth. Here, we hypothesized that continuous wheat cultivation would lead to lower glucose release, resulting in lower microbial growth, activity, and biomass. For the first time in situ glucose imaging was optimized for studying these interactions in the field - using installed root windows in the first (W1) and third (W3) wheat after break crop plots. Root and leaf samples were collected to determine the expression of sugar transporter genes using transcriptomics. Soil microbial respiration (characterized by Substrate Induced Growth Respiration (SIGR)) and enzyme kinetics (measured by fluorometric microplate assays of 4-methylumbelliferone (MUF) and 7-amino-4-methyl coumarin (AMC)) were measured in rhizosphere, root affected and bulk soil samples to assess C, N, and P acquisition.W3 had the lowest proportion of hotspots for glucose release with 1.35 % of the total soil surface area, indicating a 17.7 % decline compared to W1. Also, we found that the expressions of functional orthologous genes of SWEET1a in wheat roots were significantly upregulated in W3 compared to W1. Furthermore, total microbial biomass dropped by 11.8 and 4.8 % in W3 in the rhizosphere and bulk soils compared to W1, respectively. The growing microbial biomass in the rhizosphere soil of W1 was about five times higher than W3. For β-glucosidase activity, soil samples from W1 had a higher maximum velocity of enzyme activity (Vmax) compared to W3 samples, in all studied compartments (rhizosphere, root affected and bulk soil samples). Lower glucose release in W3 highlights the importance of root exudates in shaping rhizosphere interactions and microbial community dynamics in response to continuous wheat cultivation. Also, differences in SWEET gene expression in wheat roots and leaves, indicates shifts in nutrient uptake and resource allocation strategies. This decline in glucose release observed under W3 compared to W1 underscores the significance of root exudates in shaping rhizosphere interactions.Overall, the shift in glucose release is linked to altered root physiology and exudation processes, potentially reflecting the plant's strategy to create a less favorable environment for ambuscade and opportunistic pathogens. Hence, this study provides novel insights into the complex interactions between continuous wheat cultivation, root exudation, microbial dynamics, gene expression, and enzymatic activities.
Cloud-feedbacks in global km-scale earth system model simulations
Authors: Moon Ja-Yeon , Lee Sun-Seon , Timmermann Axel , Streffing Jan , Semmler Tido , Jung Thomas
Published: March 2024

Clouds are an important regulator of earth’s radiation balance. Therefore, future changes in clouds and corresponding feedbacks are likely to influence global climate sensitivity. How clouds respond to greenhouse warming on global and regional scales is still not well understood. Here we present first results from a km-scale, cloud-permitting greenhouse warming simulation conducted with the coupled OpenIFS-FESOM2 model (AWI-CM3) with ~9 km atmosphere resolution, 137 vertical levels and  4-15 km variable ocean resolution. Our analysis is based on a  set of 10-year time-slice simulations, which branched off from a lower-resolution (31 km) SSP585 transient scenario run with relatively high climate sensitivity. We will quantify the effect of atmosphere resolution and cloud granularity on cloud radiative feedbacks. We will further present results from the calculation of radiative kernels to determine the role of high cloud feedbacks in polar amplification. 
“rswap” – an R package for automated and command-based interaction with the SWAP4.2 model.
Authors: Shore Moritz , Farkas Csilla
Published: March 2024

“rswap” is an R package under development for SWAP 4.2 with the goal of simplifying, automating, and improving user interaction with the model. The package functions by detecting and translating SWAP input files into R-compatible dataframes, allowing for easy and automated modifications to parameters. Modified model inputs can then be re-written to files and run in SWAP from the R console using "rswap". SWAP model output can be automatically imported into the R environment and visualized using a variety of (interactive) graphing functions. If observational data is provided by the user, then the package can adjust output settings to match (variables and depth).  Modelled and observed data can then be graphically compared in-line and “goodness-of-fit” statistics can be generated and plotted. Additionally, model runs can be saved and interactively compared with each other, functions are thoroughly documented with runnable examples, and a baseline runnable model setup can be automatically initialized. Further planned developments to the package include support for parallel running of model runs, enabling rapid automated sensitivity analysis, scenario analysis, as well as automated “hard calibration” routines and parameter estimation. Through this functionality, “rswap” can connect the SWAP model to an integrated development environment (IDE), such as “RStudio”, allowing users to efficiently perform all their work (setup, calibration, execution, analysis) in a single environment. Importantly, the packages allows for direct use of  SWAP with the vast array of research software on the R platform. “rswap” is an open-source project originally developed for use in OPTAIN (optain.eu) and has been applied in multiple case studies and thesis projects.
Implications of dynamic topographic measurements along Africa’s passive margins
Authors: Slay Philippa , Holdt Megan , White Nicky
Published: March 2024

Earth’s topography is both isostatically and dynamically supported. Sub-crustal density anomalies, caused by convective mantle processes, generate transient vertical motion at Earth's surface, producing the dynamic component of topographic support. Residual depth measurements are a well-established proxy for quantifying dynamic topography on oceanic crust and provide an observation-led approach to probing mantle dynamics. A global database of residual depth anomalies compiled from seismic reflection profiles and wide-angle seismic experiments is augmented with results obtained from interpreting further seismic experiments in the oceans surrounding the African continent. Residual depth anomalies are calculated by isolating and removing isostatic signals arising from sediment loading and crustal heterogeneity. Following these corrections, observed water-loaded depth-to-basement is compared to that predicted by the plate cooling model, with deviation equal to the residual depth anomaly. Coverage surrounding the African continent is improved, particularly in the Gulf of Guinea and Mozambique Channel. Results are consistent with previous observations, showing dynamic support of ± 1 km out to and including spherical harmonic degree l = 40 (i.e. ~ 1000 km). Results are corroborated by independent geologic and geophysical markers of subsidence and uplift. For example, volcanism and slow shear-wave upper mantle velocity anomalies associated with the Cameroon Volcanic Line indicate dynamic support. Improving the spatial sampling of residual depth anomalies provides insight into the influence of convective circulation on Earth’s surface, culminating in a more robust database against which geodynamic models of mantle convection can be benchmarked.
Calving dynamics and mélange buttressing conditions at the Thwaites Glacier calving face
Authors: Crawford Anna , Åström Jan , Benn Doug , Luckman Adrian , Gladstone Rupert , Zwinger Thomas , Robertsén Fredrik , Bevan Suzanne
Published: March 2024

Thwaites Glacier, a large outlet glacier of the West Antarctic Ice Sheet, holds over a half meter of sea level rise equivalent. The large potential contribution to sea level is concerning given that the glacier may be vulnerable to self-sustaining processes of rapid retreat due to the retrograde bed slope that characterises much of the glacier’s bed. Such a reverse-sloping bed exists behind the relatively high ridge on which the western calving front (WCF) of the Thwaites Glacier terminus currently rests. Our study focuses on the factors that control the calving dynamics of the WCF and the ability of mélange to influence these dynamics. Employing the 3D Helsinki Discrete Element Model (HiDEM), we find that calving at this location currently occurs as rifts form and widen due to longitudinal tensile stresses associated with ice flow across the grounding line. Calving is restricted in HiDEM simulations that include a constricted mélange field that is confined within the bounds of the model domain. A thicker, constricted mélange field fully suppresses calving. These simulations show the development of robust force chains that transmit resistive forces to the Thwaites WCF. In the future, the ability for mélange to influence the calving dynamics at the WCF will depend on the degree to which it is constrained in the wide Amundsen Sea Embayment, either through binding in land-fast sea ice or jamming behind large, grounded icebergs. As such, sea-ice conditions and iceberg characteristics will need to be considered along with the presence of mélange in investigations of the future retreat of the prominently recognised Thwaites Glacier.
Hydraulic Stimulation Experiments in a Decimeter-scale True Triaxial Compressive Apparatus
Authors: Osten Julian , Jalali Mohammadreza , Cadmus Alexander , Welsing Leonie , Schaber Tom , Cook Paul , Guglielmi Yves , Fuentes Raul , Amann Florian
Published: March 2024

Geothermal energy is considered a sustainable energy source for the transition to a carbon-neutral economy. In Central Europe, sufficiently hot source rocks are buried deep underground and comprise tight crystalline basement formations. To extract their thermal energy, hydraulic stimulation is used to create efficient heat exchangers in the context of Enhanced Geothermal Systems (EGS). Successful geothermal reservoir initiation requires a broad understanding of the hydro-mechanical coupling in fractured rock masses. For this reason, a decimeter-scale true-triaxial setup has been developed to conduct injection-driven shear tests under various stress conditions.To gain a deeper insight into the hydro-mechanical processes involved in hydraulic stimulation, a true triaxial compressive apparatus at the decimeter scale is employed. The experimental setup consists of 30 x 30 x 45 cm cuboidal granite specimens, each containing an oblique saw-cut laboratory fracture with different surface properties. The fracture is crossed by two boreholes equipped with packers to isolate a fracture interval. Fluid injection into the isolated intervals follows the typical HTPF (hydraulic testing of pre-existing fractures) scheme, including stepwise pressure increases and decreases. Stress boundary conditions are introduced by three sets of oil-filled flatjacks, contained within a steel frame which allows a more realistic and accurate replication of the stress conditions experienced by geological formations during hydraulic stimulation experiments. Stresses for individual tests are manipulated from hydrostatic to strike-slip conditions to test for different end member states of slip tendency. Fracture and rock deformations are recorded by 16 linear variable differential transformer (LVDT) sensors mounted externally along the edges of the specimen, volume changes in the flatjacks and a newly developed borehole deformation probe (mini-SIMFIP).
Investigation of solar flares showing quasi-periodicity based on STIX Quick-Look light curves
Authors: Szaforz Żaneta , Mrozek Tomasz , Tomczak Michał
Published: March 2024

The emission of radiation associated with the release of energy in solar flares is in many cases modulated according to a quasi-oscillatory pattern. This behavior is known as Quasi-Periodic Pulsations (QPPs). STIX instrument on board  Solar Orbiter offers new opportunities to study these types of phenomena. We reviewed Quick-Look light curves of the STIX instrument recorded from the beginning of the mission (April 14, 2020) to the end of March 202. 129 flares with the clearest pulses were selected, for which the periodicity analysis was carried out using the Lomb-Scargle periodogram and the autocorrelation method. It was found that 70% of those flares showed statistically significant oscillations. The observed periods ranged from 43 to 1355 s. It was found that longer periods occur less frequently than shorter ones. It has also been shown that there is a relationship between the period and the time interval in which the oscillations were observed.
A Streamlined Neural Network Architecture for Magnetic Data Inversion
Authors: Shi Xiaoqing , Geng Hua , Liu shuang
Published: March 2024

Data-driven methods based on deep learning have been applied to magnetic inversion and achieved excellent results. However, the existing neural network structures used for inversion are relatively complex, resulting in increased computational costs. Different from the inversion structure of existing encoder-decoder structures, this study designed a streamlined neural network inversion architecture based on the characteristics of magnetic anomaly forward modeling. The network structure only contains a decoder that maps magnetic anomaly data to a three-dimensional magnetic susceptibility model, which can save computational costs. First, the single-channel input data is transformed into multi-channel data through a transformation, then it is transformed into the dimensions of the magnetic susceptibility model through a four-layer decoder, and then the multi-channel data is transformed into a single channel through transformation, and finally the output is 3D magnetic susceptibility model. The transformation coefficients are trained by neural network. The neural network structure designed by this method is interpretable. It can reduce the parameters that need to be trained, reduce training time, and achieve high accuracy. It was verified through simulated and measured magnetic anomaly data, and high-precision inversion results were obtained. This idea can also be generalized to the inversion of other data.
The history of deep-water upwelling and heat delivery to the Amundsen Sea Embayment, West Antarctica: a palaeoceanographic perspective
Authors: Smith James A. , Radionovskaya Svetlana , Mawbey Elaine M. , Hillenbrand Claus-Dieter , Wellner Julia S. , Klages Johann ,   THOR team
Published: March 2024

Thwaites and Pine Island glaciers serve as main outlets for ice draining the West Antarctic Ice Sheet into the Amundsen Sea Embayment (ASE). Observational records show that these ice streams exhibit continuous and substantial thinning and grounding-line retreat since the 1940s, particularly accelerating from the 1990s onwards . Furthermore, modeling studies suggest that ASE glaciers are susceptible to runaway retreat. Thus, the rate and magnitude of potential mass loss from these ice streams presents a major source of uncertainty for future sea level rise predictions.Ocean-driven melting of the underside of ASE glacier ice-shelves, caused by the upwelling of warm Circumpolar Deep Water (CDW) at the shelf break and its advection across the continental shelf, is thought to be the main driver of mass loss. CDW upwelling onto the ASE shelf has varied due to natural decadal variability, longer centennial variability as well recent changes in anthropogenic forcing (Holland et al., 2022). However, regional observational records are limited to the last few decades, and the onset and evolution of the oceanic forcing, prior to the instrumental period, remains uncertain. Here, we present high-resolution foraminiferal geochemical data from marine sediment cores recovered from the ASE shelf, including material collected during the Thwaites Glacier Offshore Research (THOR) expeditions in 2019, 2020 and 2021. Preliminary Mg/Ca records of benthic foraminifera shells, a proxy for bottom-water temperature, accompanied by benthic foraminiferal δ13C records, used as a water mass tracer, reveal that CDW incursions onto the ASE shelf contributed to glacier retreat on centennial to millennial timescales. Future work will aim to further constrain changes in CDW advection to the inner ASE shelf, particularly in western Pine Island Bay and at the Dotson Ice Shelf front, for the 20th century and beyond.
Joint inversion for Vp, Vs, and Vp/Vs of subduction zone in northern Chile
Authors: Chen Zixin , Zhang Haijiang , Gao Lei
Published: March 2024

We collected earthquake waveform data recorded by permanent seismic stations in northern Chile from 2014 to 2019 to construct a new earthquake catalog, and integrated them with the previous catalog data. In total, the new catalog consisted of 536342 P and 453920 S arrival times from 52165 earthquakes and 245 stations. We resolved Vp, Vs, and Vp/Vs models and seismic locations for northern Chile by using a new version of double-difference seismic tomography method based on Vp/Vs model consistency constraint (Guo et al., 2018). The new velocity models provide a refined structure of the subducting slab down to 350 km.The earthquake relocations reveal a distinct double seismic zone in northern Chile, but the gap between the two seismic planes disappears at a depth of approximately 100 km and replaced by a concentration of seismic cluster. Under this intermediate-depth seismic cluster, several isolated small seismic clusters remain. The tomography results indicate a strong correlation between seismicity distribution and high-velocity anomalies. The subducting Nazca Plate presents stripe-like high-velocity anomalies with clear segmentations, potentially related to the weakening at the outer-rise of the trench. Furthermore, our Vp/Vs model indicates that the upper seismic plane exhibits high Vp/Vs anomalies, which may indicate the presence of fluids released from dehydration reactions of various hydrous minerals. In contrast, lower seismic plane and deep seismic clusters are associated with low Vp/Vs anomalies, which could be related to supercritical fluids. Additionally, the enhanced seismicity and velocity anomalies in the region of 21-22ºS along the strike suggest a potential influence of the subduction of the Iquique Ridge of the Nazca Plate.
Aerosol Transport from the Asian Summer Monsoon into the Arctic Lower Stratosphere
Authors: Tritscher Ines , Graßl Sandra , Ritter Christoph , Vogel Bärbel
Published: March 2024

The Asian summer monsoon is linked to deep convection over the Indian subcontinent and to an anticyclonic flow that extends from the upper troposphere into the lower stratosphere region. This allows both gas-phase aerosol precursors and aerosol particles from surface sources to reach the stratosphere. The horizontal transport out of the Asian monsoon anticyclone towards the extratropical lower stratosphere of the Northern Hemisphere is the focus of this study.We present an annual record of Lidar observations at AWIPEV in Ny-Ålesund. The data record is free from obvious layers like polar stratospheric clouds, volcanic eruptions or forest fires. Nevertheless, the lower stratosphere reveals an annual cycle with lower backscatter values in winter and spring and higher backscatter values in summer and autumn. The Lidar measurements have been linked to backward trajectory calculations and simulations of artificial surface origin tracers with the three-dimensional Chemical Lagrangian Model of the Stratosphere (CLaMS). The simulations show that air masses observed above Ny-Ålesund have been transported from surface sources in Asia into the Arctic lower stratosphere. Thus, the increased backscatter values during summer and autumn can be explained by transport of aerosol particles from the Asian summer monsoon into the Arctic lower stratosphere.