bluuebunny/crossref_metadata_2025 huggingface dataset:
Do leaf phytochemical fingerprints vary with mycorrhizal association?
Authors: Guzman Thomas , Petriacq Pierre , Gibon Yves , Valls-Fonayet Josep , Dussarrat Thomas , Devert Nicolas , Cassan Cédric , Flandin Amélie , Wingate Lisa
Published: March 2024

Mycorrhizal symbiosis is a ubiquitous plant-fungal association widespread across the plant kingdom. Considering the different characteristics and distributions of arbuscular (AM) and ectomycorrhizal (EM) fungal types across biomes, mycorrhizal types can be associated with different climatic and edaphic conditions, reinforced by feedback between soil conditions and plant traits. Although it is becoming clear that AM and EM trees differ in leaf litter quality and nutrient acquisition strategies, studies investigating how leaf traits differ across mycorrhizal associations have led to contrasting results. Here for the first time, we used a combination of quantitative targeted measurements and an untargeted metabolomic approach on 32 European tree species to demonstrate that AM and EM-associated tree species show distinct leaf metabolic fingerprints. Finally, we discuss the link between AM and EM function with key leaf metabolites that emerged from our integrated metabolomic approach.
Simulations of the three-dimensional structure of instabilities beneath shoaling internal waves
Authors: Stastna Marek , Castro-Folker Nico
Published: March 2024

The simulation of instability and transport in the bottom boundary layer by internal solitary waves has been documented for over twenty years.  However, the challenge of shallow slopes and a disparity of scales between the large scale wave and the small scale boundary layer has proven challenging for simulations.  We present laboratory scale simulations that resolve the three-dimensionalisation in the boundary layer during the entire shoaling process.  We find that the late stage, in which the incoming wave fissions into boluses, provides the most consistent source of three-dimensionalisation.  In the early stage of shoaling, three-dimensionalisation occurs not so much due to separation bubble instability, but to the interaction of vortices shed from the separation bubble with the overlying pycnocline.
How Volcanic Aerosols Globally Inhibit Precipitation
Authors: McGraw Zachary , Polvani Lorenzo M.
Published: March 2024

Observations and models have indicated a reduction in global mean precipitation during the years following major volcanic eruptions, yet why this occurs has not been rigorously established. Here we apply an energy budget framework to identify the mechanisms behind reduced post-eruption precipitation. Volcanic aerosols alter the atmosphere’s energy balance, with a precipitation (latent heating) response being one pathway that returns the atmosphere towards equilibrium. Using global climate model simulations, we demonstrate that post-eruption precipitation reduction is primarily a consequence of Earth’s surface and troposphere cooling in response to reflection of sunlight by volcanic aerosols. Additionally, these aerosols directly add energy to the atmosphere by absorbing outgoing longwave radiation, which causes much of the precipitation decline in the first post-eruption year. We further identify mechanisms that limit the post-eruption decline, most prominently the influence of a warmer stratosphere. Lastly, we demonstrate that our results are robust across climate models.
Impact of soil and vegetation characteristics on CH4 fluxes in Arctic wetlands of the Northwest Territories, Canada 
Authors: Ivanova Kseniia , Goeckede Mathias , Vogt Judith , Kuechenmeister Annelen
Published: March 2024

Arctic wetlands have been identified as significant emitters of CH4, accounting for about 2% of the global methane budget, but the underlying processes remain poorly constrained. These wetlands show not only a considerable variability in CH4 flux estimates, but also varying levels of emissions between different regions and even among various elements within the same wetland. The pronounced spatial variability in ecosystem characteristics across scales requires observational approaches that can cover larger landscapes while still being capable of resolving fine-scale details.This study presents findings based on flux chamber measurements with a portable gas greenhouse analyser for CH4/CO2/H2O (LI-7810), conducted at the Trail Valley Creek research station in the Canadian NW Territories. We collected data from two polygonal mires and a small gulley, all plots organized as transects across moisture gradients. Our approach included analysing variations in CH4 fluxes across microsites within wetland complexes, such as rims, trenches, or polygon centres. In addition to greenhouse gas signals, we examined soil parameters (pH, temperature, moisture) and vegetation (height, composition, green fraction) to understand their influence on CH4 fluxes. Random forest models highlighted soil moisture at 12 cm as a primary control factor, explaining 41% of the predictive power and demonstrating higher accuracy compared to linear models for CH4 flux prediction. Based on partial dependence analyses, we classified our measurements into three groups based on soil moisture at 12 cm. In the low moisture scenario, soil moisture at deeper levels (30 cm) was more influential, while in medium moisture conditions, soil temperature at 10 and 20 cm depths played a crucial role. In the high moisture category, the presence of Carex aquatilis was a key factor influencing the CH4 flux. Our study also showed that the CH4 flux varied significantly among different wetland elements. The gully area showed the lowest rate, whereas the polygonal mires had higher fluxes. Notably, within a polygonal mire, the rim exhibited lower flux compared to the wet polygonal centres and trenches, the latter showing the highest emissions. These findings underscore the complexity and variability of CH4 fluxes in Arctic wetland ecosystems and highlight the importance of considering both soil and vegetation characteristics in understanding and predicting CH4 emissions from these critical regions.The authors acknowledge funding from the European Research Council (ERC synergy project Q-Arctic, grant agreement no. 951288).
Application of machine-learning methods to the climate of the past millennium
Authors: Zorita Eduardo
Published: March 2024

Reconstructing and analysing the climate of the past millennium has traditionally involved using statistical methods to calibrate annually resolved proxies. It also increasingly requires analysing large data sets from ensembles of long climate simulations and paleoclimate reanalysis. The accurate annual dating of most proxies and the increasingly large data sets make machine-learning methods an attractive tool to re-calibrate proxy records and investigate the causality of past climate variability, e.g. extreme events. The available log climate simulations also offer a pre-training data set for other machine-learning applications in climate research, for which the observational records are usually too short. In this talk, I will present a few examples of the application of machine-learning methods to these goals.  Climate reconstructions based on annually resolved proxies can now be produced with methods (Gaussian Process Regression or Long Short Term Memory Networks) that can better preserve the statistical properties of the target variable, like the past amplitude of variations and serial autocorrelation. Causality analysis of past variability episodes, including extremes, can be investigated in climate simulations with  Random Forest and Layerwise Relevance Propagation in neural networks. Finally, data assimilation methods, which blend proxy and model data into a single reconstruction, can be augmented with methods of the family of K-Nearest-Neighbour, thereby also providing an attribution of past climate episodes to one external forcing.  
Investigations into GNSS clock biases in a global network of IGS H-Maser stations
Authors: Widczisk Jari Simon , Männel Benjamin , Wickert Jens
Published: March 2024

Global Navigation Satellite Systems (GNSS) are based on measuring the time that elapses between the signal’s transmission at the satellite and its reception on the ground. Therefore, clock information is required on both sides. While the GNSS satellites are equipped with atomic clocks, ground stations usually use the time information from the internal oscillator of their GNSS receiver, which has a much lower time-keeping performance compared to the satellite clocks. Nevertheless, some continuously operated tracking stations obtain their time information from an external atomic clock, as it is the case with many stations of the International GNSS Service (IGS).To compensate for synchronization errors, current GNSS analysis models generally introduce clock biases for satellites and receivers into the observation equations. The often-made assumption of a pure white noise behavior for the estimated clocks may lead to high correlations with other geodetic parameters, such as the radial orbit error for the satellite clock, or the station height coordinate and tropospheric delay parameters for the station clock. A general solution to this problem is to reduce the amount of unknown clock parameters by modeling them in the adjustment process. In order to be modeled adequately, the corresponding clock must have a high degree of stability, which is particularly crucial for the ground stations.In this contribution, we investigate the clock stability of globally distributed IGS tracking stations. Those IGS stations, that are steered by an external Hydrogen-Maser (H-Maser) clock, are considered in a global network analysis over a period of several weeks. The generated clock products are used to compare the frequency stabilities within the station network, as well as with the mean behavior of GPS and Galileo satellite blocks. After some further research on stations with significantly higher deviations, the final result of this contribution will be a set of reliable ground stations, that will serve as a basis for future clock modeling approaches at GFZ.
The "XEGCat project" - The subsurface monitoring network for shallow geothermal research in urban areas of Catalonia
Authors: Herms Ignasi , Arnó Georgina , Camps Víctor , Colomer Montse , Armengol Sandra , Caldera Norbert , Orriols Ernest , Marcè Toni , Elvira Àlex , Jara Jose Antonio , Struth Lucia , Garcia-Céspedes Jordi , Piris Guillem
Published: March 2024

The "XEGCat project" is a project funded by the ICGC Contract Program initiated in 2019. The objective is the implementation of instrumented boreholes designed to collect relevant scientific data on the thermal behavior of the subsoil. This data can be utilized for assessment, modeling, and the creation of maps depicting the shallow geothermal resources (SGR) on the urban scale. It also aids in the simulation and design of specific projects involving GSHP. Additionally, the project will allow long-term research on the progress of the subsurface urban heat island effect. The potential for deploying sustainable SGR schemes in the subsoil depends on the geological and hydrogeological characteristics of the subsoil, as well as the distribution of temperature at depth. Therefore, understanding these variables is crucial for assessing their potential use. The networks consist of instrumented boreholes equipped with sensors of various characteristics to measure and automatically record the subsoil temperature at different depths, and the position of the piezometric level in the existing subsoil and aquifers. The acquisition systems are equipped with dataloggers, and SIM cards powered by a 30 W photovoltaic panel. This setup enables automatic transmission of data to the ICGC server or storage on site, to be periodically collected in the field. The data is uploaded and organized by the NetMon© spatial database management system. Through a web service, the data can be consulted, analyzed, and downloaded using the ICGC viewer - Geoindex XEGCat. The data is also utilized by ICGC to develop new 3D subsoil models. By the end of 2023, up to two networks have been deployed: one in the city of Girona (NE, Catalonia) and another in the city of Tarragona (SE, Catalonia). A third specific local network has been deployed in the Aran Valley in the town of Vielha (Catalan Pyrenees). Over the next two years, there are plans to deploy a new urban network in the city of Lleida (W, Catalonia).
Unveiling the Multifaceted Hazard Risks of Volcanic Eruptions: The case of Kolumbo submarine volcano
Authors: Katsigera Anna , Nomikou Paraskevi , Pavlopoulos Kosmas , Polymenakou Paraskevi , Karantzalos Konstantinos , Mallios Aggelos , Scire Scapuzzo Sergio Simone , Rizzo Andrea Luca , Lazaro Gianluca , Longo Manfredi , D'Alessandro Walter , Grassa Fausto , Heimbürger-Boavida Lars-Eric , Ntouskos Valsamis , Antoniou Christos , Spanos Sotiris
Published: March 2024

Volcanic eruptions stand as formidable threats to adjacent communities, unleashing a spectrum of hazards such as earthquakes, tsunamis, pyroclastic flows, and toxic gases. The imperative for proactive management of volcanic risks cannot be overstated, particularly in densely populated areas where the potential for widespread devastation looms large. Kolumbo, an active submerged volcano located approximately 7 kilometers northeast of Santorini Island in Greece at 500m depth, serves a pertinent case. Its historical record is marred by an eruption in 1650 AD which triggered a relentless tsunami. The aftermath witnessed havoc on neighboring islands, coupled with casualties stemming from noxious gases in Santorini. Eyewitness accounts mention maximum water run-up heights of 20m on the southern coast of Ios, a staggering 240m inundation on Sikinos, and a disconcerting flooding of up to 2km² of land on the eastern coast of Santorini.Recent studies suggest that a potential future explosive eruption of Kolumbo poses a substantial hazard to the northern and eastern coasts of Santorini. Unfortunately, the absence of a concrete management protocol, leaves these areas vulnerable to an impending threat that demands immediate attention. Therefore, it is recommended that a comprehensive approach be adopted, involving scientific research (active monitoring, hazard maps), community engagement, preparedness planning with government agencies, and the development of timely response strategies to reduce the associated risks, prevent casualties, and mitigate the consequences on the region's economy and infrastructure. Our team has multidisciplinary data from past oceanographic expeditions that will help us to understand Kolumbo’s behavior. These include a) High-resolution multibeam bathymetry data and optical data., b) a dense network of sub-seafloor seismic reflection profiles, c) a series of the seafloor and sub-seafloor samples of microbial mat and sediments, d) CTD data, e) several polymetallic (Au, Ag, As, Sb, Pb, Hg, Mo, Zn, Cu, Tl) CO2 diffuser chimney samples and f) tephra in marine sediment cores. Despite the current knowledge that we managed to obtain, monitoring is needed to efficiently assess potential hazards and create early warning systems and management protocols for an imminent eruption from Kolumbo. In the current context, advanced sensors have been deployed to monitor Kolumbo's active hydrothermal field as part of the SANTORY project. The SANTORY project aims to create innovative communication tools and establish interregional monitoring protocols, providing the scientific community, policymakers, and stakeholders with the means to assess hazard warning codes effectively.
Superstatistical analysis of HF Radar sea surface currents in the Gulf of Trieste, their idealized wind-driven stochastic modeling and extreme power-input events
Authors: Flora Sofia , Ursella Laura , Wirth Achim
Published: March 2024

The increasing amount of data in earth-observing systems allows us to move from considering low-order moments (means and variances) of fluctuating observations to their PDFs (Probability Density Functions). For two years of HFR (High Frequency Radar) sea surface current increments in the Gulf of Trieste (Northern Adriatic Sea) we found the analytical fat-tailed PDF form (a combination of a gaussian and a convolution of two exponentials) using superstatistics and the maximum entropy principle twice: on a short and on a longer time scale. The data observed under different wind regimes (Bora, Sirocco and low wind, from the WRF model local forecasts) follow the same analytical PDF, pointing towards a universal behaviour.We developed an idealised deterministic-stochastic model of the wind-driven sea surface currents in the Gulf of Trieste. The deterministic model consists of a time-dependent Ekman layer system, including the tidal signal, with a quadratic drag. It describes 57% of the variability, missing the fast fluctuations. The stochastic part accounts for the fast fluctuations, reproducing the superstatistical PDFs from the observations. The model, providing a huge amount of data, allows for studying the PDF of the mechanical power-input into the ocean and the associated extreme events.
Body tides and elastic stresses in the Earth’s crust
Authors: Greff-Lefftz Marianne , Métivier Laurent
Published: March 2024

Solid tides, predominantly diurnal and semi-diurnal, are commonly observed on Earth's surface through horizontal and vertical movements (a few tens of centimeters), along with gravity measurements (~100 microgal). This study focuses specifically on tidal effects within the elastic stress field at the surface, which is approximately 1000 Pascals.We initially established a correlation between tidal elastic pressure and natural hydrogen emission. Hydrogen, in its gaseous form, escaping from Proterozoic basins, represents a potential source of carbon-free energy, leading to extensive research on vents. A notable characteristic of these emissions is the consistent daily cycle observed in specific regions. While atmospheric pressure effects have been shown to account for this cycle, solid tides could serve as an alternative explanation. Considering that tidal waves do not have a uniform spatial distribution on the Earth's surface, we computed time series of elastic pressure at two locations where natural hydrogen emissions are observed: one near the equator in the Sao Francisco basin (Brazil) and another near the North Pole in the Lovozero deposits (Kola Peninsula).We then explored the maximum shear stress generated by tidal potential in areas experiencing tectonic stresses. We demonstrated that in expansive regions, the maximum shear stress correlates with the peak of the tidal potential, while in compressive regions, it is associated with the minimum tidal peak.
Continental back-arc extension, molten lower crust and syn-kinematic granites: insights from Cycladic MCCs
Authors: Jolivet Laurent , Arbaret Laurent , Augier Romain
Published: March 2024

Rifting in back-arc basins is characterized by large extension rates, low-angle normal faults and metamorphic core complexes (MCC) displaying partially molten cores and granitic intrusions. The Aegean metamorphic core complexes (MCC) were exhumed underneath crustal-scale detachments accommodating large displacements of the order of 50-100 km and were intruded by Miocene syn-kinematic granites. A common finite geometry and kinematics of all these detachment/pluton systems is recognized with asymmetric intrusive bodies extracted from anatectic lower crust, whose internal structure is controlled by the large-scale dynamics, from the magmatic stage to mylonitization and final exhumation in brittle conditions. Detachments are organized in sets of structures working sequentially evolving from ductile to brittle, the successive branches of the detachment being progressively inactivated by emplacing plutonic batches. The Mykonos-Delos-Rheneia (MDR) MCC shows these interactions between lower crustal migmatites and different syn-kinematic plutons. Our new detailed map of Delos (1/5000) shows geometrical and kinematic relationships between the different magmatic venues during deformation. A strong internal orientation of granites is observed from the magmatic stage until the last ultramylonites below the upper detachments. The deepest magmatic batches are rich in high-grade rocks septae and mafic enclaves, also oriented parallel to regional stretching. Evidence for magma mixing and mingling further indicates interactions with mafic venues at the base of the crust from the mantle. Large high-grade rocks septae are intensely molten and the contact zone between host gneiss and plutons shows intense migmatitization with a foliation parallel to the granite magmatic foliation. Characteristic banded facies marking the contacts between the different intrusions result from high-temperature shearing at the magmatic stage. At all scales foliation and lineation in magmatic rocks and surrounding gneisses are parallel, suggesting a similar weak rheology. Delos shows the roots of these intrusions emplaced as a large-scale sheath-fold whose axis is parallel to the regional stretching direction. The quality of outcrops in Delos, Rheneia and Mykonos, as well as the links between magma emplacement and regional tectonics makes the MDR MCC a natural laboratory for studying the interactions between magmatic intrusions and crustal deformation in tectonically active and hot contexts. In such contexts magmatic and tectonic processes in the lower and middle crusts appear closely interconnected, working at a similar pace and interacting with mantle deformation and melting.
What Proglacial Aufeis Formations Tell Us about the Evolution of Hydrological Processes in a Glacier Decline Context
Authors: Baraer Michel , Charonnat Bastien , Valence Eole , McKenzie Jeffrey , Masse-Dufresne Janie
Published: March 2024

Alpine environments in cold regions are undergoing rapid transformations due to shifting climates, raising concerns about the future of ecosystems and downstream water supplies. Traditionally, hydrological studies have focused on visible cryospheric elements, often overlooking buried features like permafrost, ice-cored moraines, and rock glaciers, as well as the significance of groundwater in alpine valleys. Recent investigations, however, highlight the pivotal role of groundwater in shaping local watershed dynamics and regional water resources in these cold regions. Understanding hydrogeology in cold region alpine environments presents challenges due to remote and inaccessible study sites and harsh winter conditions. Recent studies suggest that the winter hydrogeological dynamics of proglacial areas are captured within proglacial aufeis, ice formations persisting during winter despite extended sub-zero temperatures. This study focuses on aufeis formation within a tributary of the Duke Valley, a glacierized catchment in the green belt of Mount St-Elias on the Kluane First Nation territory in Yukon. Employing a field-based approach at the Shar Shäw Tágà study site and remote sensing analysis using satellite imagery, our research aims to delineate key aufeis growth stages and identify contributing water sources. The field study, conducted from 2018 to 2023, utilizes time-lapse imagery, hydrochemical tracers, and meteorological records to reveal aufeis growth variability. Observations in Shar Shäw Tágà show aufeis forming consistently across most years, spanning from the canyon exit to the meander of the Grizzly Creek River. However, results indicate a three-year absence of aufeis formation and variability in formation dates when present. Notably, aufeis growth deceleration or cessation in March, despite sustained sub-zero temperatures, suggests groundwater's role. Remote sensing analysis dating back to 1974 indicates a declining trend in aufeis occurrences. Statistical analysis on relative frequencies suggests a potential link between non-formation and meteorological conditions from the preceding summer, supporting the hypothesis that aufeis occurrence is influenced by factors impacting groundwater behavior. The correlation between aufeis formation and longer-term factors implies aufeis as a valuable indicator of groundwater evolution in alpine cold regions, sensitive to processes beyond immediate seasonal variations. These findings contribute to our understanding of broader changes in groundwater behavior over extended periods in these dynamic environments.
Quantitative the urban vegetation carbon storage by constructing seamless and dense time series remote sensing data
Authors: Zhang Ya , Shao Zhenfeng , Xu Xiaodi , Zhuang Qingwei
Published: March 2024

 Abstract
Urban vegetation is an integral component of the terrestrial ecosystem, and accurate calculation of its carbon storage is essential. Net primary productivity (NPP), as a crucial element in the dynamic surface carbon cycle, plays a key role in characterizing the resilience of terrestrial ecosystems. It also serves as a fundamental indicator for measuring carbon storage. However, the insufficient coverage of effective image data within cities hampers the acquisition of high-quality Normalized Difference Vegetation Index (NDVI) data, posing a challenge for estimating carbon storage across different vegetation periods. Consequently, continuous monthly NPP estimation remains a challenge. In response to this issue, the primary objective of this study is to propose a novel approach for estimating intensive time series NPP by reconstructing NDVI data. We utilized the GF-SG algorithm to construct a densely sampled NDVI time series dataset by merging Landsat 8 and MODIS data, coupled with meteorological information. These inputs were then employed in an improved CASA model, enabling the generation of monthly NPP results at a 30m resolution. Using the Pearl River Delta (PRD) region as a case study, we investigated temporal and spatial variations in NPP resulting from changes in land cover and their impact on vegetation from 2017 to 2020. Our findings suggest that establishing a consistent time series of NDVI data contributes to reducing the uncertainty associated with NPP inversion outcomes. The annual cumulative NPP values varied significantly among different land cover types. Particularly, forest areas exhibited significantly higher cumulative NPP compared to other land types, with the order of NPP values being Crops>Grass>Wetlands. The transformation of land cover within the study area resulted in a substantial reduction in NPP, amounting to a decrease of 29.07 GgC. Importantly, even in the absence of image data, this method can estimate the net primary productivity of vegetation while maintaining high accuracy. Crucially, this approach can support long-term and large-scale monitoring of vegetation carbon storage within urban agglomerations.
Keywords: Urban vegetation, carbon storage, Net primary productivity, Improved temporal NDVI, High observation frequency
Variations in binding properties of dissolved organic matter along river-ocean continuum
Authors: Lodeiro Pablo , Macedo Joao C. A. , David Calin , Rey-Castro Carlos , Puy Jaume , Martínez-Cabanas María , Herrero Roberto , Sastre de Vicente Manuel E. , Barriada José L.
Published: March 2024

The binding properties of dissolved organic matter (DOM) play a crucial role in the biogeochemical cycles of trace metals and carbon. The composition of DOM is anticipated to exert influence over the magnitude and distribution of the intrinsic ion binding affinities that occur over a continuum of values, referred to as the affinity spectra. These spectra encompass many different organic acid groups that contribute to the nuanced binding characteristics of DOM. The total proton binding capacity represents the maximum sites available for other chemical species that may compete with protons for the same DOM binding sites, particularly in the case of metals. Consequently, the study of proton binding by DOM becomes the initial step to investigate deeper into metal binding mechanisms. Here, we research the variability in proton binding exhibited by DOM extracted from the Ebro and Mero Rivers (NNE and NW of Spain), and at the Atlantic Ocean and Mediterranean Sea. Our approach combines the non-ideal competitive adsorption (NICA) isotherm, offering insights into chemical binding on heterogeneous ligands, with the Donnan electrostatic model, which accounts for polyelectrolytic effects, i.e., the non-specific binding. This methodology enables us to pinpoint potential shifts in DOM binding affinities and derive a comprehensive set of intrinsic binding parameters for DOM. Importantly, these parameters are thermodynamically consistent and remain independent of the specific conditions of the samples, enhancing the extrapolation to future environmental changes. Acknowledgements: Authors thank Agencia Española de Investigación for the financial support through the research projects PID2020-117910GB-C21 and -C22/AEI/10.13039/501100011033. P.L. acknowledges current support from the Ministerio de Ciencia, Innovación y Universidades of Spain and University of Lleida (Beatriz Galindo Senior award number BG20/00104)References:[1] Lodeiro, P., Rey-Castro, C., David, C., Humphreys, M. H., Gledhill, M., 2023. Proton Binding Characteristics of Dissolved Organic Matter Extracted from the North Atlantic. Environmental Science & Technology 57, 21136–21144.[2] Waska, H., Brumsack, H.-J., Massmann, G., Koschinsky, A., Schnetger, B., Simon, H., Dittmar, T., 2019. Inorganic and organic iron and copper species of the subterranean estuary: Origins and fate. Geochimica et Cosmochimica Acta 259, 211–232.[3] Heerah, K. M.,  Reade, H. E., 2023. Towards the identification of humic ligands associated with iron transport through a salinity gradient. Scientific Reports 12:15545.
Laboratory tests and modeling of a reactive multibarrier for the remediation of a contaminated aquifer system
Authors: Sethi Rajandrea , Magherini Leonardo , Bianco Carlo
Published: March 2024

This study presents the treatability tests and modeling aimed at dimensioning of an in-situ reactive multibarrier, designed to purify an aquifer contaminated with a range of chlorinated organic compounds and arsenic, with 1,2-dichloroethane (1,2-DCA) presenting a significant resistance to conventional treatments.The remediation strategy involves the implementation of a reactive multibarrier system comprising  two series-connected reactive filters: the first filled with millimetric zerovalent iron (ZVI) to remove arsenic and most of the chlorinated hydrocarbons through abiotic reductive dehalogenation, and the second with granular activated carbon (GAC) to adsorb 1,2-DCA and other residual organic contaminants.To optimize the site-specific design and sizing of the reactive filters, groundwater treatability tests were conducted in the laboratory. Initial batch tests compared various ZVI and GAC types to select the most effective materials. Subsequent column tests assessed the treatment chain's efficacy under flow conditions and determined the longevity of the reactive materials. The results demonstrated the multibarrier's high effectiveness, with the ZVI filter removing 99.9% of several chlorinated solvents and all arsenic, and GAC achieving complete removal of the remaining contaminants to meet water quality standards. Mathematical models were employed to interpret the experimental findings and provide quantitative parameters essential for designing a large-scale multibarrier, such as kinetic constants for contaminant removal, reactive material longevity, and reagent volumes. A multicomponent adsorption model specifically aided in designing the GAC filtration step. he preliminary results of the pilot test, which is still ongoing, confirmed the potentiality of the reactive multibarrier to effectively remediate groundwater in site-specific conditions.
Legacy  of drained northern landscapes: consequences of rewetting and ditch cleaning on hydrology and water quality .
Authors: Mosquera Virginia , Hasselquist Eliza , Laudon Hjalmar
Published: March 2024

Drainage for forestry has created ~1 million km of artificial waterways in Sweden, making it one of the largest human-induced environmental disturbances in the country. These extensive modifications of both peatland and mineral soil dominated landscapes still carry largely unknown, but potentially enormous environmental legacy effects. However, the consequences of contemporary ditch management strategies, such as hydrological restoration via ditch blocking or enhancing forest drainage to promote biomass production via ditch cleaning, on water resources are unclear. To close the gap between science and management, we have developed a unique field research platform to experimentally evaluate key environmental strategies for drained northern landscapes with the aim to avoid further environmental degeneration. The Trollberget Experimental Area (TEA) includes replicated and controlled treatments applied at the catchment scale based on a BACI approach (before-after and control-impact). The treatments represent the dominant ecosystem types impacted by ditching in Sweden and the boreal zone: 1) rewetting of a drained peatland, 2) ditch cleaning in productive upland forests and 3) leaving these ditches unmanaged. Here we describe the TEA platform, report initial results, suggest ways forward for how to best manage this historical large-scale alteration of the boreal landscape, as well as warn against applying these treatments broadly before more long-term results are reported.  
Effects of long-term residue return on nutrient content, ecological and economic benefits of black soil in Northeast China
Authors: Zhang Yang , Liang Aizhen
Published: March 2024

Improved tillage practice plays a positive role in restoring degraded cropland, maintaining crop productivity, and mitigating climate change, which has been proposed as a sustainable agricultural technology. Based on a long-term experiment in black soil area of Northeast China, effects of different tillage practices on soil organic carbon (SOC) and nutrient content were explored, and ecological and economic benefits were also evaluated. Three tillage practices were included: conventional tillage with complete removal of residue (CT), moldboard plowing with residue return (MP) and no-tillage with residue return (NT). As the trial period increased, the SOC content of the CK decreased in the 0-20 cm soil layer, while the total nitrogen (TN) content remained. Residue return treatments (MP and NT) increased SOC and TN content. The SOC and TN were uniformly distributed in the 0-20 cm soil layer of MP, whereas the SOC and TN increased significantly in the 0-5 cm soil layer of NT, especially during the 5-8 years of the experiment. The total phosphorus (TP) and total potassium (TK) contents of all treatments slowly increased over time, and there was no significant difference among treatments. Compared with CT, NT could reduce N2O emissions and absorb more CH4, whereas MP significantly increased CO2 emissions from soil. Moreover, NT led to both the lowest GHG emissions from soil (GWPGHG) and agricultural inputs (AIGHG), thus reduced approximately 40% carbon footprint (CF) compared to CT. However, no significant difference in maize yield and net ecosystem ecological benefit (NEEB) were observed among three tillage practices, although MP and NT showed lower investments during maize production than CK. In conclusion, NT could not only enhance the SOC and nutrient content but also minimize CF while ensuring economic benefit from a long-term perspective. Long-term NT can be implemented in Northeast China and similar agro-eco-regions around the world.
A high-resolution nested model to study the effects of alkalinity additions in a mid-latitude coastal fjord
Authors: Laurent Arnaud , Wang Bin , Pei Qiantong , Ohashi Kyoko , Sheng Jinyu , Garcia Larez Edmundo , Fradette Caroline , Rakshit Subhadeep , Atamanchuk Dariia , Azetsu-Scott Kumiko , Algar Chris , Wallace Doug , Burt Will , Fennel Katja
Published: March 2024

Surface ocean alkalinity enhancement (OAE), through the release of alkaline materials, is an emerging carbon dioxide removal (CDR) technology that could increase the storage of anthropogenic carbon in the ocean. Although essential, evaluating the effects of alkalinity additions on the carbonate system and ultimately on air-sea CO2 fluxes is not straight forward. Observations, even with autonomous platforms, are inherently sparse and limited, and therefore cannot provide a comprehensive quantification of the effects of OAE. Numerical models are important complementary tools. They can help guide fieldwork design, provide forecasts of the ocean state, and simulate the effects of alkalinity additions on the seawater carbonate system. Here we describe a coupled physical-biogeochemical implementation of ROMS in a nested grid configuration that reaches a very high spatial resolution in Bedford Basin (51m), a coastal fjord in eastern Canada that is chosen as a test site for OAE. The biogeochemical model simulates oxygen dynamics and the carbonate system, including air-sea gas exchange. We present a multi-year hindcast validated against the long-term weekly time series available at the Compass Buoy station in the centre of the Basin as well as recent simulations carried out during alkalinity addition trials. We will discuss the model’s capabilities with respect to OAE and the challenges ahead.
Modeling suspended sediment concentration using artificial neural networks, an effort towards global sediment flux observations in rivers from space
Authors: Vieira Lucchese Luisa , Daroya Rangel , Simmons Travis , Prum Punwath , Maji Subhransu , Pavelsky Tamlin , Gleason Colin , Gardner John
Published: March 2024

Harmonized Landsat Sentinel-2 (HLS) provides high-quality images every 2-3 days across Earth. However, HLS has not been widely used to measure Suspended Sediment Concentration (SSC) in rivers. Here, we used HLS to generate a fully open-source, open-architecture, and scalable image processing workflow and Neural Network algorithm to estimate SSC in global rivers. The extracted HLS surface reflectance was joined with global in-situ SSC measurements and used to train an ensemble of Artificial Neural Networks (ANN). Two ANNs were developed: one trained based on the lower SSC values (up to 20.08 mg/L) and the other one trained based on higher SSC values (up to 403.43 mg/L). The ANNs were able to achieve satisfactory performances for a global SSC model, with a median absolute error of 5.10 mg/L, pairwise correlation of 0.457, absolute E90 of 46.85 mg/L and absolute E95 of 84.9 mg/L. The preprocessing module and the ANN models were optimized to have few dependencies and finish execution within a reasonable timeframe (the ANN models are executed in approximately 1 second per node). These characteristics make the model suitable for implementation on Amazon Web Services (AWS) cloud, where they are planned to automatically generate SSC data on-the-fly. We will combine the global SSC model with Surface Water and Ocean Topography (SWOT) discharge data to generate a self-updating, global sediment flux dataset to be made available in the National Aeronautics and Space Administration (NASA) PO.DAAC portal.
Could continuous cover forestry on drained peatlands increase the carbon sink of Finnish forests? 
Authors: Lehtonen Aleksi , Eyvindson Kyle , Härkönen Kari , Leppä Kersti , Salmivaara Aura , Peltoniemi Mikko , Salminen Olli , Sarkkola Sakari , Launiainen Samuli , Ojanen Paavo , Räty Minna , Mäkipää Raisa
Published: March 2024

Land-based mitigation measures are needed to achieve climate targets. One option is mitigation of currently high greenhouse gas (GHG) emissions of nutrient-rich drained peatland forest soils. Continuous cover forestry (CCF) has been proposed as a measure to manage this GHG emission source; however, its emission reduction potential and impact on timber production at regional and national scale have not been analysed.To quantify the potential emission reduction, we simulated four management scenarios for Finnish forests: (i) clearcutting of nutrient-rich drained peatlands replaced by selection harvesting (CCF) and (ii) the current prevailing forest management regime (BAU), and both at two harvest levels, namely (i) the mean annual harvesting (2016–2018) and (ii) the maximum sustainable yield. The simulations were conducted with a forest simulator (MELA) coupled with hydrological model (SpaFHy), soil C model (Yasso07) and empirical GHG exchange models.Simulations showed that the management scenario (CCF) that avoided clear-cutting on nutrient-rich drained peatlands produced approximately 1 Tg CO2 eq. higher carbon sinks annually compared to the BAU at equal harvest level for Finland. This emission reduction can be attributed to the maintenance of higher biomass sink and to the mitigation of soil emissions from nutrient-rich drained peatland sites.
Overview of Ion-Driven Instabilities in the Inner Heliosphere
Authors: Martinović Mihailo , Klein Kristopher
Published: March 2024

Linear theory is a well-established theoretical framework proven to accurately characterize instabilities in the solar wind weakly collisional plasma. We aim to describe the statistical properties of linear ion-driven instabilities between 0.3 and 1 au. We analyzed ∼1.5M proton and alpha particle Velocity Distribution Functions (VDFs) observed by Helios I & II, and ~5M VDFs observed by Wind, using Plasma in a Linear Uniform Magnetized Environment (PLUME) dispersion solver to calculate growth rate, frequency, wavevector, and the power emitted or absorbed by each VDF component. The descriptive statistical analysis shows that the stability of the solar wind is primarily determined by the collisional processing, rather than the distance from the Sun. We use this data set to train Stability Analysis Vitalizing Instability Classification (SAVIC) Machine Learning algorithm capable to classify the predicted unstable modes into physically meaningful “textbook” types. This method enables us to map the instability properties in multi-dimensional phase space. The proton-core-induced Ion Cyclotron (IC) mode dominates the collisionally young solar wind, while the alpha population plays more important role in the wave energy dynamics of the older wind. We also demonstrate that the proton beam population is not affected by the collisions and has the core-beam drift as the main source of free energy that determines its overall behavior in the solar wind. SAVIC code used here is publicly available for the community.
Using discrete element methods to understand in-plane fragmentation of sea ice floes
Authors: Bateson Adam , Feltham Daniel , Schröder David , Durski Scott , Hutchings Jennifer , Basu Rajlaxmi , Hwang Byongjun
Published: March 2024

Sea ice floe size can impact several processes that determine the evolution of the Arctic sea ice, including lateral melt volume, momentum exchange, and rheology. Floe size distribution (FSD) models are applied within continuum sea ice models to capture the evolution of the FSD through parameterisations of the processes that modify floe size such as lateral melting and wave break-up of floes. FSD models do not yet adequately resolve in-plane fragmentation processes of floes such as the breakup of floes under wind forcing, through interactions between neighbouring floes, or through thermal weakening. It is challenging to characterise and therefore parameterise these in-plane floe breakup processes due to limited availability of in-situ observations. Discrete element models (DEMs) offer an alternative way to understand the different mechanisms of floe fragmentation. By resolving relevant properties such as shear and normal stress and sea ice strength at the sub-floe scale, it is possible to use DEMs as a virtual laboratory and directly simulate the break-up of floes into smaller fragments.In this study, we describe how in-situ observations of sea ice can be combined with output from sea ice DEMs to develop parameterisations of in-plane breakup of floes that can then be applied in continuum models. We then discuss the necessary model developments in order to apply a sea ice DEM to floe fragmentation at smaller scales. We will also present results from a series of DEM simulations used to model the fracture of sea ice under different forcing conditions and with varying sea ice states to identify the important sea ice parameters and processes in determining the size of the floes that form from in-plane breakup events.
From seismic re-processing to mechanic modelling, a new interpretation of the TRANSALP seismic section as a base for future geothermal energy projects, lower Inn Valley, Tyrol, Austria
Authors: Hinterwirth Simon , Ortner Hugo , Schreilechner Marcellus , Binder Heinz , Lüschen Ewald , Jud Makus , Hoyer Stefan , Bottig Magdalena , Hintersberger Esther
Published: March 2024

In western Austria, especially in Tyrol, the potential for geothermal energy use is unexplored. The project GeoEN Inntal is aiming to determine this potential and the risks for the use of geothermal energy in a complex tectonic setting in the Inn valley. The valley is bordered by the Permo-Mesozoic sedimentary succession of the Northern Calcareous Alps in the north and the south-east, as well as Upper Austroalpine basement units in the south. Since the early Late Cretaceous, during Eoalpine orogeny, the Austroalpine basement and its Mesozoic cover were involved in nappe stacking and folding. The nappe stack was again refolded and faulted in the Palaeocene-Eocene collision of Adria and the European distal margin, as well as in Oligocene-Miocene, when post-collisional processes lead to an eastward extrusion of crustal blocks, out-of-sequence thrusting and the development of major faults. One of these faults is the Inntal shear zone, a sinistral ENE-trending shear zone, controlling the course of the Inn valley (“Inntal” in German). The shear zone has a multi-phase activity and is kinematically linked with the Brenner normal fault south of Innsbruck, the Alpine basal thrust at the Alpine front, and the Sub-Tauern ramp, rooting below the Tauern window. As the deep subsurface of the Inn valley was only explored geophysically, but no exploration boreholes were drilled, little is known about these structures at depth. Here we present the reprocessed Inntal part of the TRANSALP seismic section, which serves as a base for multidisciplinary modelling approaches. As part of the GeoEN Inntal project, we present first results from our 3D modelling of fault geometry, results from mechanical modelling of the Inntal shear zone, as well as first temperature gradient assessment from hydrological modelling.